patchcheckout & worktree: introduce a core.DWIMRemote setting

Documentation/config.txt, Documentation/git-checkout.txt, Documentation/git-worktree.txt, builtin/checkout.c, checkout.c, t/t2024-checkout-dwim.sh, t/t2025-worktree-add.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 2659153cb3..d4740fcdb9 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -898,6 +898,21 @@ core.notesRef::
 This setting defaults to "refs/notes/commits", and it can be overridden by
 the `GIT_NOTES_REF` environment variable.  See linkgit:git-notes[1].
 
+core.DWIMRemote::
+	Various git commands will look at references on the configured
+	remotes and DW[YI]M (Do What (You|I) Mean) if the reference
+	only exists on one remote. This setting allows for setting the
+	name of a special remote that should always win when it comes
+	to disambiguation. The typical use-case is to set this to
+	`origin`.
++
+Currently this is used by linkgit:git-checkout[1] when `git checkout
+<something>' will checkout the '<something>' branch on another remote,
+and linkgit:git-worktree[1] when 'git worktree add' similarly DWYM
+when a branch is unique across remotes, or this setting is set to a
+special remote. This setting might be used for other commands or
+functionality in the future when appropriate.
+
 core.sparseCheckout::
 	Enable "sparse checkout" feature. See section "Sparse checkout" in
 	linkgit:git-read-tree[1] for more information.
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index ca5fc9c798..8ad7be6c53 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -38,6 +38,11 @@ equivalent to
 $ git checkout -b <branch> --track <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes the `core.DWIMRemote`
+variable can be used to pick the remote you really mean. Set it to
+e.g. `core.DWIMRemote=origin` to always checkout remote branches from
+there. See also `core.DWIMRemote` in linkgit:git-config[1].
++
 You could omit <branch>, in which case the command degenerates to
 "check out the current branch", which is a glorified no-op with
 rather expensive side-effects to show only the tracking information,
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index 2755ca90e3..37db12f816 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -60,6 +60,11 @@ with a matching name, treat as equivalent to:
 $ git worktree add --track -b <branch> <path> <remote>/<branch>
 ------------
 +
+It's also possible to use the `core.DWIMRemote` setting to designate a
+special remote this rule should be applied to, even if the branch
+isn't unique across all remotes. See `core.DWIMRemote` in
+linkgit:git-config[1].
++
 If `<commit-ish>` is omitted and neither `-b` nor `-B` nor `--detach` used,
 then, as a convenience, a new branch based at HEAD is created automatically,
 as if `-b $(basename <path>)` was specified.
diff --git a/builtin/checkout.c b/builtin/checkout.c
index b49b582071..8622ad4ef1 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -903,7 +903,8 @@ static int parse_branchname_arg(int argc, const char **argv,
 	 *   (b) If <something> is _not_ a commit, either "--" is present
 	 *       or <something> is not a path, no -t or -b was given, and
 	 *       and there is a tracking branch whose name is <something>
-	 *       in one and only one remote, then this is a short-hand to
+	 *       in one and only one remote (or if the branch exists on the
+	 *       remote named in core.DWIMRemote), then this is a short-hand to
 	 *       fork local <something> from that remote-tracking branch.
 	 *
 	 *   (c) Otherwise, if "--" is present, treat it like case (1).
diff --git a/checkout.c b/checkout.c
index ac42630f74..6e474fbfbb 100644
--- a/checkout.c
+++ b/checkout.c
@@ -1,12 +1,15 @@
 #include "cache.h"
 #include "remote.h"
 #include "checkout.h"
+#include "config.h"
 
 struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
 	int unique;
+	const char *dwim_remote;
+	char *dwim_dst_ref;
 };
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
@@ -20,6 +23,8 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		free(query.dst);
 		return 0;
 	}
+	if (cb->dwim_remote && !strcmp(remote->name, cb->dwim_remote))
+		cb->dwim_dst_ref = xstrdup(query.dst);
 	if (cb->dst_ref) {
 		free(query.dst);
 		cb->unique = 0;
@@ -31,13 +36,21 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 
 const char *unique_tracking_name(const char *name, struct object_id *oid)
 {
-	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
+	const char *dwim_remote = NULL;
+	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1, NULL, NULL };
+	if (!git_config_get_string_const("core.dwimremote", &dwim_remote))
+		cb_data.dwim_remote = dwim_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	free(cb_data.src_ref);
-	if (cb_data.unique)
+	free((char *)dwim_remote);
+	if (cb_data.unique) {
+		free(cb_data.dwim_dst_ref);
 		return cb_data.dst_ref;
+	}
 	free(cb_data.dst_ref);
+	if (cb_data.dwim_dst_ref)
+		return cb_data.dwim_dst_ref;
 	return NULL;
 }
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 3e5ac81bd2..d8db2a14d7 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -68,6 +68,16 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_branch master
 '
 
+test_expect_success 'checkout of branch from multiple remotes succeeds with core.DWIMRemote #1' '
+	git checkout -B master &&
+	test_might_fail git branch -D foo &&
+
+	git -c core.DWIMRemote=repo_a checkout foo &&
+	test_branch foo &&
+	test_cmp_rev remotes/repo_a/foo HEAD &&
+	test_branch_upstream foo repo_a foo
+'
+
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	git checkout -B master &&
 	test_might_fail git branch -D bar &&
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index d0d2e4f7ec..6be4cd03da 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -450,6 +450,24 @@ test_expect_success 'git worktree --no-guess-remote option overrides config' '
 	)
 '
 
+test_expect_success '"add" <path> <branch> dwims with core.DWIMRemote' '
+	test_when_finished rm -rf repo_upstream repo_dwim foo &&
+	setup_remote_repo repo_upstream repo_dwim &&
+	git init repo_dwim &&
+	(
+		cd repo_dwim &&
+		git remote add repo_upstream2 ../repo_upstream &&
+		git fetch repo_upstream2 &&
+		test_must_fail git worktree add ../foo foo &&
+		git -c core.DWIMRemote=repo_upstream worktree add ../foo foo
+	) &&
+	(
+		cd foo &&
+		test_branch_upstream foo repo_upstream foo &&
+		test_cmp_rev refs/remotes/repo_upstream/foo refs/heads/foo
+	)
+'
+
 post_checkout_hook () {
 	gitdir=${1:-.git}
 	test_when_finished "rm -f $gitdir/hooks/post-checkout" &&

Documentation/config.txt, Documentation/git-checkout.txt, Documentation/git-worktree.txt, builtin/checkout.c, checkout.c, t/t2024-checkout-dwim.sh, t/t2025-worktree-add.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 2659153cb3..83460bd443 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1084,6 +1084,23 @@ browser.<tool>.path::
 	browse HTML help (see `-w` option in linkgit:git-help[1]) or a
 	working repository in gitweb (see linkgit:git-instaweb[1]).
 
+checkout.implicitRemote::
+	When you run 'git checkout <something>' and only have one
+	remote, it may implicitly fall back on checking out and
+	tracking e.g. 'origin/<something>'. This stops working as soon
+	as you have more than one remote with a '<something>'
+	reference. This setting allows for setting the name of a
+	special remote that should always win when it comes to
+	disambiguation. The typical use-case is to set this to
+	`origin`.
++
+Currently this is used by linkgit:git-checkout[1] when 'git checkout
+<something>' will checkout the '<something>' branch on another remote,
+and by linkgit:git-worktree[1] when 'git worktree add' when referring
+to a remote branch.  This setting might be used for other
+checkout-like commands or functionality in the future when
+appropriate.
+
 clean.requireForce::
 	A boolean to make git-clean do nothing unless given -f,
 	-i or -n.   Defaults to true.
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index ca5fc9c798..753aa4001f 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -38,6 +38,12 @@ equivalent to
 $ git checkout -b <branch> --track <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes the `checkout.implicitRemote`
+variable can be used to pick the remote you really mean. Set it to
+e.g. `checkout.implicitRemote=origin` to always checkout remote
+branches from there. See also `checkout.implicitRemote` in
+linkgit:git-config[1].
++
 You could omit <branch>, in which case the command degenerates to
 "check out the current branch", which is a glorified no-op with
 rather expensive side-effects to show only the tracking information,
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index 2755ca90e3..35798a1132 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -60,6 +60,11 @@ with a matching name, treat as equivalent to:
 $ git worktree add --track -b <branch> <path> <remote>/<branch>
 ------------
 +
+It's also possible to use the `checkout.implicitRemote` setting to
+designate a special remote this rule should be applied to, even if the
+branch isn't unique across all remotes. See `checkout.implicitRemote`
+in linkgit:git-config[1].
++
 If `<commit-ish>` is omitted and neither `-b` nor `-B` nor `--detach` used,
 then, as a convenience, a new branch based at HEAD is created automatically,
 as if `-b $(basename <path>)` was specified.
diff --git a/builtin/checkout.c b/builtin/checkout.c
index b49b582071..495a5d7955 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -903,8 +903,10 @@ static int parse_branchname_arg(int argc, const char **argv,
 	 *   (b) If <something> is _not_ a commit, either "--" is present
 	 *       or <something> is not a path, no -t or -b was given, and
 	 *       and there is a tracking branch whose name is <something>
-	 *       in one and only one remote, then this is a short-hand to
-	 *       fork local <something> from that remote-tracking branch.
+	 *       in one and only one remote (or if the branch exists on the
+	 *       remote named in checkout.implicitRemote), then this is a
+	 *       short-hand to fork local <something> from that
+	 *       remote-tracking branch.
 	 *
 	 *   (c) Otherwise, if "--" is present, treat it like case (1).
 	 *
diff --git a/checkout.c b/checkout.c
index ac42630f74..2c898cfe19 100644
--- a/checkout.c
+++ b/checkout.c
@@ -1,12 +1,15 @@
 #include "cache.h"
 #include "remote.h"
 #include "checkout.h"
+#include "config.h"
 
 struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
 	int unique;
+	const char *implicit_remote;
+	char *implicit_dst_ref;
 };
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
@@ -20,6 +23,8 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		free(query.dst);
 		return 0;
 	}
+	if (cb->implicit_remote && !strcmp(remote->name, cb->implicit_remote))
+		cb->implicit_dst_ref = xstrdup(query.dst);
 	if (cb->dst_ref) {
 		free(query.dst);
 		cb->unique = 0;
@@ -31,13 +36,21 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 
 const char *unique_tracking_name(const char *name, struct object_id *oid)
 {
-	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
+	const char *implicit_remote = NULL;
+	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1, NULL, NULL };
+	if (!git_config_get_string_const("checkout.implicitremote", &implicit_remote))
+		cb_data.implicit_remote = implicit_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	free(cb_data.src_ref);
-	if (cb_data.unique)
+	free((char *)implicit_remote);
+	if (cb_data.unique) {
+		free(cb_data.implicit_dst_ref);
 		return cb_data.dst_ref;
+	}
 	free(cb_data.dst_ref);
+	if (cb_data.implicit_dst_ref)
+		return cb_data.implicit_dst_ref;
 	return NULL;
 }
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 3e5ac81bd2..da6bd74bbc 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -68,6 +68,16 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_branch master
 '
 
+test_expect_success 'checkout of branch from multiple remotes succeeds with checkout.implicitRemote #1' '
+	git checkout -B master &&
+	test_might_fail git branch -D foo &&
+
+	git -c checkout.implicitRemote=repo_a checkout foo &&
+	test_branch foo &&
+	test_cmp_rev remotes/repo_a/foo HEAD &&
+	test_branch_upstream foo repo_a foo
+'
+
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	git checkout -B master &&
 	test_might_fail git branch -D bar &&
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index d0d2e4f7ec..6eb994ac12 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -450,6 +450,24 @@ test_expect_success 'git worktree --no-guess-remote option overrides config' '
 	)
 '
 
+test_expect_success '"add" <path> <branch> dwims with checkout.implicitRemote' '
+	test_when_finished rm -rf repo_upstream repo_dwim foo &&
+	setup_remote_repo repo_upstream repo_dwim &&
+	git init repo_dwim &&
+	(
+		cd repo_dwim &&
+		git remote add repo_upstream2 ../repo_upstream &&
+		git fetch repo_upstream2 &&
+		test_must_fail git worktree add ../foo foo &&
+		git -c checkout.implicitRemote=repo_upstream worktree add ../foo foo
+	) &&
+	(
+		cd foo &&
+		test_branch_upstream foo repo_upstream foo &&
+		test_cmp_rev refs/remotes/repo_upstream/foo refs/heads/foo
+	)
+'
+
 post_checkout_hook () {
 	gitdir=${1:-.git}
 	test_when_finished "rm -f $gitdir/hooks/post-checkout" &&

Documentation/config.txt, Documentation/git-checkout.txt, Documentation/git-worktree.txt, builtin/checkout.c, checkout.c, t/t2024-checkout-dwim.sh, t/t2025-worktree-add.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 84e2891aed..7f095a260a 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1098,6 +1098,22 @@ browser.<tool>.path::
 	browse HTML help (see `-w` option in linkgit:git-help[1]) or a
 	working repository in gitweb (see linkgit:git-instaweb[1]).
 
+checkout.implicitRemote::
+	When you run 'git checkout <something>' and only have one
+	remote, it may implicitly fall back on checking out and
+	tracking e.g. 'origin/<something>'. This stops working as soon
+	as you have more than one remote with a '<something>'
+	reference. This setting allows for setting the name of a
+	preferred remote that should always win when it comes to
+	disambiguation. The typical use-case is to set this to
+	`origin`.
++
+Currently this is used by linkgit:git-checkout[1] when 'git checkout
+<something>' will checkout the '<something>' branch on another remote,
+and by linkgit:git-worktree[1] when 'git worktree add' refers to a
+remote branch. This setting might be used for other checkout-like
+commands or functionality in the future.
+
 clean.requireForce::
 	A boolean to make git-clean do nothing unless given -f,
 	-i or -n.   Defaults to true.
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index ca5fc9c798..753aa4001f 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -38,6 +38,12 @@ equivalent to
 $ git checkout -b <branch> --track <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes the `checkout.implicitRemote`
+variable can be used to pick the remote you really mean. Set it to
+e.g. `checkout.implicitRemote=origin` to always checkout remote
+branches from there. See also `checkout.implicitRemote` in
+linkgit:git-config[1].
++
 You could omit <branch>, in which case the command degenerates to
 "check out the current branch", which is a glorified no-op with
 rather expensive side-effects to show only the tracking information,
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index afc6576a14..6febb21dca 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -60,6 +60,11 @@ with a matching name, treat as equivalent to:
 $ git worktree add --track -b <branch> <path> <remote>/<branch>
 ------------
 +
+The `checkout.implicitRemote` setting can be used to to designate a
+preferred `<remote>` this rule should be applied to, even if the
+`<branch>` isn't unique across all remotes. See
+`checkout.implicitRemote` in linkgit:git-config[1].
++
 If `<commit-ish>` is omitted and neither `-b` nor `-B` nor `--detach` used,
 then, as a convenience, the new worktree is associated with a branch
 (call it `<branch>`) named after `$(basename <path>)`.  If `<branch>`
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 2b3b768eff..88e650f0f8 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -909,8 +909,10 @@ static int parse_branchname_arg(int argc, const char **argv,
 	 *   (b) If <something> is _not_ a commit, either "--" is present
 	 *       or <something> is not a path, no -t or -b was given, and
 	 *       and there is a tracking branch whose name is <something>
-	 *       in one and only one remote, then this is a short-hand to
-	 *       fork local <something> from that remote-tracking branch.
+	 *       in one and only one remote (or if the branch exists on the
+	 *       remote named in checkout.implicitRemote), then this is a
+	 *       short-hand to fork local <something> from that
+	 *       remote-tracking branch.
 	 *
 	 *   (c) Otherwise, if "--" is present, treat it like case (1).
 	 *
diff --git a/checkout.c b/checkout.c
index ac42630f74..2c898cfe19 100644
--- a/checkout.c
+++ b/checkout.c
@@ -1,12 +1,15 @@
 #include "cache.h"
 #include "remote.h"
 #include "checkout.h"
+#include "config.h"
 
 struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
 	int unique;
+	const char *implicit_remote;
+	char *implicit_dst_ref;
 };
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
@@ -20,6 +23,8 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		free(query.dst);
 		return 0;
 	}
+	if (cb->implicit_remote && !strcmp(remote->name, cb->implicit_remote))
+		cb->implicit_dst_ref = xstrdup(query.dst);
 	if (cb->dst_ref) {
 		free(query.dst);
 		cb->unique = 0;
@@ -31,13 +36,21 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 
 const char *unique_tracking_name(const char *name, struct object_id *oid)
 {
-	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
+	const char *implicit_remote = NULL;
+	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1, NULL, NULL };
+	if (!git_config_get_string_const("checkout.implicitremote", &implicit_remote))
+		cb_data.implicit_remote = implicit_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	free(cb_data.src_ref);
-	if (cb_data.unique)
+	free((char *)implicit_remote);
+	if (cb_data.unique) {
+		free(cb_data.implicit_dst_ref);
 		return cb_data.dst_ref;
+	}
 	free(cb_data.dst_ref);
+	if (cb_data.implicit_dst_ref)
+		return cb_data.implicit_dst_ref;
 	return NULL;
 }
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 3e5ac81bd2..da6bd74bbc 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -68,6 +68,16 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_branch master
 '
 
+test_expect_success 'checkout of branch from multiple remotes succeeds with checkout.implicitRemote #1' '
+	git checkout -B master &&
+	test_might_fail git branch -D foo &&
+
+	git -c checkout.implicitRemote=repo_a checkout foo &&
+	test_branch foo &&
+	test_cmp_rev remotes/repo_a/foo HEAD &&
+	test_branch_upstream foo repo_a foo
+'
+
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	git checkout -B master &&
 	test_might_fail git branch -D bar &&
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index 2240498924..271a6413f0 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -402,6 +402,24 @@ test_expect_success '"add" <path> <branch> dwims' '
 	)
 '
 
+test_expect_success '"add" <path> <branch> dwims with checkout.implicitRemote' '
+	test_when_finished rm -rf repo_upstream repo_dwim foo &&
+	setup_remote_repo repo_upstream repo_dwim &&
+	git init repo_dwim &&
+	(
+		cd repo_dwim &&
+		git remote add repo_upstream2 ../repo_upstream &&
+		git fetch repo_upstream2 &&
+		test_must_fail git worktree add ../foo foo &&
+		git -c checkout.implicitRemote=repo_upstream worktree add ../foo foo
+	) &&
+	(
+		cd foo &&
+		test_branch_upstream foo repo_upstream foo &&
+		test_cmp_rev refs/remotes/repo_upstream/foo refs/heads/foo
+	)
+'
+
 test_expect_success 'git worktree add does not match remote' '
 	test_when_finished rm -rf repo_a repo_b foo &&
 	setup_remote_repo repo_a repo_b &&

diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 3e5ac81bd2..29c1eada17 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -23,6 +23,12 @@ test_branch_upstream () {
 	test_cmp expect.upstream actual.upstream
 }
 
+status_uno_is_clean() {
+	>status.expect &&
+	git status -uno --porcelain >status.actual &&
+	test_cmp status.expect status.actual
+}
+
 test_expect_success 'setup' '
 	test_commit my_master &&
 	git init repo_a &&
@@ -55,6 +61,7 @@ test_expect_success 'checkout of non-existing branch fails' '
 	test_might_fail git branch -D xyzzy &&
 
 	test_must_fail git checkout xyzzy &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/xyzzy &&
 	test_branch master
 '
@@ -64,8 +71,10 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_might_fail git branch -D foo &&
 
 	test_must_fail git checkout foo &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/foo &&
-	test_branch master
+	test_branch master &&
+	status_uno_is_clean
 '
 
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
@@ -73,6 +82,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	test_might_fail git branch -D bar &&
 
 	git checkout bar &&
+	status_uno_is_clean &&
 	test_branch bar &&
 	test_cmp_rev remotes/repo_a/bar HEAD &&
 	test_branch_upstream bar repo_a bar
@@ -83,6 +93,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #2' '
 	test_might_fail git branch -D baz &&
 
 	git checkout baz &&
+	status_uno_is_clean &&
 	test_branch baz &&
 	test_cmp_rev remotes/other_b/baz HEAD &&
 	test_branch_upstream baz repo_b baz
@@ -90,6 +101,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #2' '
 
 test_expect_success '--no-guess suppresses branch auto-vivification' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D bar &&
 
 	test_must_fail git checkout --no-guess bar &&
@@ -99,6 +111,7 @@ test_expect_success '--no-guess suppresses branch auto-vivification' '
 
 test_expect_success 'setup more remotes with unconventional refspecs' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	git init repo_c &&
 	(
 		cd repo_c &&
@@ -128,27 +141,33 @@ test_expect_success 'setup more remotes with unconventional refspecs' '
 
 test_expect_success 'checkout of branch from multiple remotes fails #2' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D bar &&
 
 	test_must_fail git checkout bar &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/bar &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch from multiple remotes fails #3' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D baz &&
 
 	test_must_fail git checkout baz &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/baz &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch from a single remote succeeds #3' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	git checkout spam &&
+	status_uno_is_clean &&
 	test_branch spam &&
 	test_cmp_rev refs/remotes/extra_dir/repo_c/extra_dir/spam HEAD &&
 	test_branch_upstream spam repo_c spam
@@ -156,9 +175,11 @@ test_expect_success 'checkout of branch from a single remote succeeds #3' '
 
 test_expect_success 'checkout of branch from a single remote succeeds #4' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D eggs &&
 
 	git checkout eggs &&
+	status_uno_is_clean &&
 	test_branch eggs &&
 	test_cmp_rev refs/repo_d/eggs HEAD &&
 	test_branch_upstream eggs repo_d eggs
@@ -166,32 +187,38 @@ test_expect_success 'checkout of branch from a single remote succeeds #4' '
 
 test_expect_success 'checkout of branch with a file having the same name fails' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	test_must_fail git checkout spam &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/spam &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch with a file in subdir having the same name fails' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	mkdir sub &&
 	mv spam sub/spam &&
 	test_must_fail git -C sub checkout spam &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/spam &&
 	test_branch master
 '
 
 test_expect_success 'checkout <branch> -- succeeds, even if a file with the same name exists' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	git checkout spam -- &&
+	status_uno_is_clean &&
 	test_branch spam &&
 	test_cmp_rev refs/remotes/extra_dir/repo_c/extra_dir/spam HEAD &&
 	test_branch_upstream spam repo_c spam
@@ -200,6 +227,7 @@ test_expect_success 'checkout <branch> -- succeeds, even if a file with the same
 test_expect_success 'loosely defined local base branch is reported correctly' '
 
 	git checkout master &&
+	status_uno_is_clean &&
 	git branch strict &&
 	git branch loose &&
 	git commit --allow-empty -m "a bit more" &&
@@ -210,7 +238,9 @@ test_expect_success 'loosely defined local base branch is reported correctly' '
 	test_config branch.loose.merge master &&
 
 	git checkout strict | sed -e "s/strict/BRANCHNAME/g" >expect &&
+	status_uno_is_clean &&
 	git checkout loose | sed -e "s/loose/BRANCHNAME/g" >actual &&
+	status_uno_is_clean &&
 
 	test_cmp expect actual
 '

diff --git a/checkout.h b/checkout.h
index 9980711179..4cd4cd1c23 100644
--- a/checkout.h
+++ b/checkout.h
@@ -8,6 +8,7 @@
  * tracking branch.  Return the name of the remote if such a branch
  * exists, NULL otherwise.
  */
-extern const char *unique_tracking_name(const char *name, struct object_id *oid);
+extern const char *unique_tracking_name(const char *name,
+					struct object_id *oid);
 
 #endif /* CHECKOUT_H */

checkout.c, checkout.h

diff --git a/checkout.c b/checkout.c
index bdefc888ba..8d68f75ad1 100644
--- a/checkout.c
+++ b/checkout.c
@@ -3,13 +3,6 @@
 #include "refspec.h"
 #include "checkout.h"
 
-struct tracking_name_data {
-	/* const */ char *src_ref;
-	char *dst_ref;
-	struct object_id *dst_oid;
-	int unique;
-};
-
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
 	struct tracking_name_data *cb = cb_data;
diff --git a/checkout.h b/checkout.h
index 4cd4cd1c23..04b52f9ffe 100644
--- a/checkout.h
+++ b/checkout.h
@@ -3,6 +3,13 @@
 
 #include "cache.h"
 
+struct tracking_name_data {
+	/* const */ char *src_ref;
+	char *dst_ref;
+	struct object_id *dst_oid;
+	int unique;
+};
+
 /*
  * Check if the branch name uniquely matches a branch name on a remote
  * tracking branch.  Return the name of the remote if such a branch

checkout.c, checkout.h

diff --git a/checkout.c b/checkout.c
index 8d68f75ad1..629fc1d5c4 100644
--- a/checkout.c
+++ b/checkout.c
@@ -25,7 +25,7 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 
 const char *unique_tracking_name(const char *name, struct object_id *oid)
 {
-	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
+	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
diff --git a/checkout.h b/checkout.h
index 04b52f9ffe..a61ec93e65 100644
--- a/checkout.h
+++ b/checkout.h
@@ -10,6 +10,8 @@ struct tracking_name_data {
 	int unique;
 };
 
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 1 }
+
 /*
  * Check if the branch name uniquely matches a branch name on a remote
  * tracking branch.  Return the name of the remote if such a branch

checkout.c, checkout.h

diff --git a/checkout.c b/checkout.c
index 629fc1d5c4..7ce5306bc7 100644
--- a/checkout.c
+++ b/checkout.c
@@ -14,9 +14,9 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		free(query.dst);
 		return 0;
 	}
+	cb->num_matches++;
 	if (cb->dst_ref) {
 		free(query.dst);
-		cb->unique = 0;
 		return 0;
 	}
 	cb->dst_ref = query.dst;
@@ -30,7 +30,7 @@ const char *unique_tracking_name(const char *name, struct object_id *oid)
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	free(cb_data.src_ref);
-	if (cb_data.unique)
+	if (cb_data.num_matches == 1)
 		return cb_data.dst_ref;
 	free(cb_data.dst_ref);
 	return NULL;
diff --git a/checkout.h b/checkout.h
index a61ec93e65..2decb9b820 100644
--- a/checkout.h
+++ b/checkout.h
@@ -7,10 +7,10 @@ struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
-	int unique;
+	int num_matches;
 };
 
-#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 1 }
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0 }
 
 /*
  * Check if the branch name uniquely matches a branch name on a remote

diff --git a/builtin/checkout.c b/builtin/checkout.c
index ec7cf93b4a..423e056acd 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1266,9 +1266,11 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	}
 
 	UNLEAK(opts);
-	if (opts.patch_mode || opts.pathspec.nr)
-		return checkout_paths(&opts, new_branch_info.name,
-				      &dwim_remotes_matched);
-	else
+	if (opts.patch_mode || opts.pathspec.nr) {
+		int ret = checkout_paths(&opts, new_branch_info.name,
+					 &dwim_remotes_matched);
+		return ret;
+	} else {
 		return checkout_branch(&opts, &new_branch_info);
+	}
 }

builtin/checkout.c, builtin/worktree.c, checkout.c, checkout.h

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 2e1d2376d2..ec7cf93b4a 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -239,7 +239,8 @@ static int checkout_merged(int pos, const struct checkout *state)
 }
 
 static int checkout_paths(const struct checkout_opts *opts,
-			  const char *revision)
+			  const char *revision,
+			  int *dwim_remotes_matched)
 {
 	int pos;
 	struct checkout state = CHECKOUT_INIT;
@@ -878,7 +879,8 @@ static int parse_branchname_arg(int argc, const char **argv,
 				int dwim_new_local_branch_ok,
 				struct branch_info *new_branch_info,
 				struct checkout_opts *opts,
-				struct object_id *rev)
+				struct object_id *rev,
+				int *dwim_remotes_matched)
 {
 	struct tree **source_tree = &opts->source_tree;
 	const char **new_branch = &opts->new_branch;
@@ -972,7 +974,8 @@ static int parse_branchname_arg(int argc, const char **argv,
 			recover_with_dwim = 0;
 
 		if (recover_with_dwim) {
-			const char *remote = unique_tracking_name(arg, rev);
+			const char *remote = unique_tracking_name(arg, rev,
+								  dwim_remotes_matched);
 			if (remote) {
 				*new_branch = arg;
 				arg = remote;
@@ -1109,6 +1112,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	struct branch_info new_branch_info;
 	char *conflict_style = NULL;
 	int dwim_new_local_branch = 1;
+	int dwim_remotes_matched = 0;
 	struct option options[] = {
 		OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
 		OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
@@ -1219,7 +1223,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 			opts.track == BRANCH_TRACK_UNSPECIFIED &&
 			!opts.new_branch;
 		int n = parse_branchname_arg(argc, argv, dwim_ok,
-					     &new_branch_info, &opts, &rev);
+					     &new_branch_info, &opts, &rev,
+					     &dwim_remotes_matched);
 		argv += n;
 		argc -= n;
 	}
@@ -1262,7 +1267,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 
 	UNLEAK(opts);
 	if (opts.patch_mode || opts.pathspec.nr)
-		return checkout_paths(&opts, new_branch_info.name);
+		return checkout_paths(&opts, new_branch_info.name,
+				      &dwim_remotes_matched);
 	else
 		return checkout_branch(&opts, &new_branch_info);
 }
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 5c7d2bb180..a763dbdccb 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -412,7 +412,7 @@ static const char *dwim_branch(const char *path, const char **new_branch)
 	if (guess_remote) {
 		struct object_id oid;
 		const char *remote =
-			unique_tracking_name(*new_branch, &oid);
+			unique_tracking_name(*new_branch, &oid, NULL);
 		return remote;
 	}
 	return NULL;
@@ -484,7 +484,7 @@ static int add(int ac, const char **av, const char *prefix)
 
 		commit = lookup_commit_reference_by_name(branch);
 		if (!commit) {
-			remote = unique_tracking_name(branch, &oid);
+			remote = unique_tracking_name(branch, &oid, NULL);
 			if (remote) {
 				new_branch = branch;
 				branch = remote;
diff --git a/checkout.c b/checkout.c
index 7ce5306bc7..c578782baa 100644
--- a/checkout.c
+++ b/checkout.c
@@ -23,12 +23,15 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 	return 0;
 }
 
-const char *unique_tracking_name(const char *name, struct object_id *oid)
+const char *unique_tracking_name(const char *name, struct object_id *oid,
+				 int *dwim_remotes_matched)
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
+	if (dwim_remotes_matched)
+		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
 	if (cb_data.num_matches == 1)
 		return cb_data.dst_ref;
diff --git a/checkout.h b/checkout.h
index 2decb9b820..4e518c801a 100644
--- a/checkout.h
+++ b/checkout.h
@@ -18,6 +18,7 @@ struct tracking_name_data {
  * exists, NULL otherwise.
  */
 extern const char *unique_tracking_name(const char *name,
-					struct object_id *oid);
+					struct object_id *oid,
+					int *dwim_remotes_matched);
 
 #endif /* CHECKOUT_H */

Documentation/config.txt, Documentation/git-checkout.txt, Documentation/git-worktree.txt, builtin/checkout.c, checkout.c, checkout.h, t/t2024-checkout-dwim.sh, t/t2025-worktree-add.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 08d3e70989..e0d92217ac 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -350,7 +350,10 @@ advice.*::
 		remote tracking branch on more than one remote in
 		situations where an unambiguous argument would have
 		otherwise caused a remote-tracking branch to be
-		checked out.
+		checked out. See the `checkout.defaultRemote`
+		configuration variable for how to set a given remote
+		to used by default in some situations where this
+		advice would be printed.
 	amWorkDir::
 		Advice that shows the location of the patch file when
 		linkgit:git-am[1] fails to apply it.
@@ -1105,6 +1108,22 @@ browser.<tool>.path::
 	browse HTML help (see `-w` option in linkgit:git-help[1]) or a
 	working repository in gitweb (see linkgit:git-instaweb[1]).
 
+checkout.defaultRemote::
+	When you run 'git checkout <something>' and only have one
+	remote, it may implicitly fall back on checking out and
+	tracking e.g. 'origin/<something>'. This stops working as soon
+	as you have more than one remote with a '<something>'
+	reference. This setting allows for setting the name of a
+	preferred remote that should always win when it comes to
+	disambiguation. The typical use-case is to set this to
+	`origin`.
++
+Currently this is used by linkgit:git-checkout[1] when 'git checkout
+<something>' will checkout the '<something>' branch on another remote,
+and by linkgit:git-worktree[1] when 'git worktree add' refers to a
+remote branch. This setting might be used for other checkout-like
+commands or functionality in the future.
+
 clean.requireForce::
 	A boolean to make git-clean do nothing unless given -f,
 	-i or -n.   Defaults to true.
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index ca5fc9c798..8cb77bddeb 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -38,6 +38,15 @@ equivalent to
 $ git checkout -b <branch> --track <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes and one of them is named by
+the `checkout.defaultRemote` configuration variable, we'll use that
+one for the purposes of disambiguation, even if the `<branch>` isn't
+unique across all remotes. Set it to
+e.g. `checkout.defaultRemote=origin` to always checkout remote
+branches from there if `<branch> is ambiguous but exists on the
+'origin' remote. See also `checkout.defaultRemote` in
+linkgit:git-config[1].
++
 You could omit <branch>, in which case the command degenerates to
 "check out the current branch", which is a glorified no-op with
 rather expensive side-effects to show only the tracking information,
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index afc6576a14..6638d5ca3d 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -60,6 +60,15 @@ with a matching name, treat as equivalent to:
 $ git worktree add --track -b <branch> <path> <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes and one of them is named by
+the `checkout.defaultRemote` configuration variable, we'll use that
+one for the purposes of disambiguation, even if the `<branch>` isn't
+unique across all remotes. Set it to
+e.g. `checkout.defaultRemote=origin` to always checkout remote
+branches from there if `<branch> is ambiguous but exists on the
+'origin' remote. See also `checkout.defaultRemote` in
+linkgit:git-config[1].
++
 If `<commit-ish>` is omitted and neither `-b` nor `-B` nor `--detach` used,
 then, as a convenience, the new worktree is associated with a branch
 (call it `<branch>`) named after `$(basename <path>)`.  If `<branch>`
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 710369a60a..78bbead000 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -913,8 +913,10 @@ static int parse_branchname_arg(int argc, const char **argv,
 	 *   (b) If <something> is _not_ a commit, either "--" is present
 	 *       or <something> is not a path, no -t or -b was given, and
 	 *       and there is a tracking branch whose name is <something>
-	 *       in one and only one remote, then this is a short-hand to
-	 *       fork local <something> from that remote-tracking branch.
+	 *       in one and only one remote (or if the branch exists on the
+	 *       remote named in checkout.defaultRemote), then this is a
+	 *       short-hand to fork local <something> from that
+	 *       remote-tracking branch.
 	 *
 	 *   (c) Otherwise, if "--" is present, treat it like case (1).
 	 *
@@ -1277,9 +1279,14 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 				 "on trying to resolve the argument as a path, but failed there too!\n"
 				 "\n"
 				 "Perhaps you meant fully qualify the branch name? E.g. origin/<name>\n"
-				 "instead of <name>?"),
+				 "instead of <name>?\n"
+				 "\n"
+				 "If you'd like to always have checkouts of '%s' prefer one remote,\n"
+				 "e.g. the 'origin' remote, consider setting checkout.defaultRemote=origin\n"
+				 "in your config. See the 'git-config' manual page for details."),
 			       argv[0],
-			       dwim_remotes_matched);
+			       dwim_remotes_matched,
+			       argv[0]);
 		return ret;
 	} else {
 		return checkout_branch(&opts, &new_branch_info);
diff --git a/checkout.c b/checkout.c
index c578782baa..e6cfe6d2ab 100644
--- a/checkout.c
+++ b/checkout.c
@@ -2,6 +2,7 @@
 #include "remote.h"
 #include "refspec.h"
 #include "checkout.h"
+#include "config.h"
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
@@ -15,6 +16,12 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		return 0;
 	}
 	cb->num_matches++;
+	if (cb->default_remote && !strcmp(remote->name, cb->default_remote)) {
+		struct object_id *dst = xmalloc(sizeof(*cb->default_dst_oid));
+		cb->default_dst_ref = xstrdup(query.dst);
+		oidcpy(dst, cb->dst_oid);
+		cb->default_dst_oid = dst;
+	}
 	if (cb->dst_ref) {
 		free(query.dst);
 		return 0;
@@ -27,14 +34,26 @@ const char *unique_tracking_name(const char *name, struct object_id *oid,
 				 int *dwim_remotes_matched)
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
+	const char *default_remote = NULL;
+	if (!git_config_get_string_const("checkout.defaultremote", &default_remote))
+		cb_data.default_remote = default_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	if (dwim_remotes_matched)
 		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
-	if (cb_data.num_matches == 1)
+	free((char *)default_remote);
+	if (cb_data.num_matches == 1) {
+		free(cb_data.default_dst_ref);
+		free(cb_data.default_dst_oid);
 		return cb_data.dst_ref;
+	}
 	free(cb_data.dst_ref);
+	if (cb_data.default_dst_ref) {
+		oidcpy(oid, cb_data.default_dst_oid);
+		free(cb_data.default_dst_oid);
+		return cb_data.default_dst_ref;
+	}
 	return NULL;
 }
diff --git a/checkout.h b/checkout.h
index 4e518c801a..e9f1372f32 100644
--- a/checkout.h
+++ b/checkout.h
@@ -8,9 +8,12 @@ struct tracking_name_data {
 	char *dst_ref;
 	struct object_id *dst_oid;
 	int num_matches;
+	const char *default_remote;
+	char *default_dst_ref;
+	struct object_id *default_dst_oid;
 };
 
-#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0 }
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0, NULL, NULL, NULL }
 
 /*
  * Check if the branch name uniquely matches a branch name on a remote
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 14735f5bb8..ccd96ba85c 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -91,6 +91,18 @@ test_expect_success 'checkout of branch from multiple remotes fails with advice'
 	test_i18ngrep ! "^hint: " stderr
 '
 
+test_expect_success 'checkout of branch from multiple remotes succeeds with checkout.defaultRemote #1' '
+	git checkout -B master &&
+	status_uno_is_clean &&
+	test_might_fail git branch -D foo &&
+
+	git -c checkout.defaultRemote=repo_a checkout foo &&
+	status_uno_is_clean &&
+	test_branch foo &&
+	test_cmp_rev remotes/repo_a/foo HEAD &&
+	test_branch_upstream foo repo_a foo
+'
+
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	git checkout -B master &&
 	test_might_fail git branch -D bar &&
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index d2e49f7632..be6e093142 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -402,6 +402,27 @@ test_expect_success '"add" <path> <branch> dwims' '
 	)
 '
 
+test_expect_success '"add" <path> <branch> dwims with checkout.defaultRemote' '
+	test_when_finished rm -rf repo_upstream repo_dwim foo &&
+	setup_remote_repo repo_upstream repo_dwim &&
+	git init repo_dwim &&
+	(
+		cd repo_dwim &&
+		git remote add repo_upstream2 ../repo_upstream &&
+		git fetch repo_upstream2 &&
+		test_must_fail git worktree add ../foo foo &&
+		git -c checkout.defaultRemote=repo_upstream worktree add ../foo foo &&
+		>status.expect &&
+		git status -uno --porcelain >status.actual &&
+		test_cmp status.expect status.actual
+	) &&
+	(
+		cd foo &&
+		test_branch_upstream foo repo_upstream foo &&
+		test_cmp_rev refs/remotes/repo_upstream/foo refs/heads/foo
+	)
+'
+
 test_expect_success 'git worktree add does not match remote' '
 	test_when_finished rm -rf repo_a repo_b foo &&
 	setup_remote_repo repo_a repo_b &&

Documentation/config.txt, advice.c, advice.h, builtin/checkout.c, t/t2024-checkout-dwim.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 7d8383433c..08d3e70989 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -344,6 +344,13 @@ advice.*::
 		Advice shown when you used linkgit:git-checkout[1] to
 		move to the detach HEAD state, to instruct how to create
 		a local branch after the fact.
+	checkoutAmbiguousRemoteBranchName::
+		Advice shown when the argument to
+		linkgit:git-checkout[1] ambiguously resolves to a
+		remote tracking branch on more than one remote in
+		situations where an unambiguous argument would have
+		otherwise caused a remote-tracking branch to be
+		checked out.
 	amWorkDir::
 		Advice that shows the location of the patch file when
 		linkgit:git-am[1] fails to apply it.
diff --git a/advice.c b/advice.c
index 370a56d054..75e7dede90 100644
--- a/advice.c
+++ b/advice.c
@@ -21,6 +21,7 @@ int advice_add_embedded_repo = 1;
 int advice_ignored_hook = 1;
 int advice_waiting_for_editor = 1;
 int advice_graft_file_deprecated = 1;
+int advice_checkout_ambiguous_remote_branch_name = 1;
 
 static int advice_use_color = -1;
 static char advice_colors[][COLOR_MAXLEN] = {
@@ -72,6 +73,7 @@ static struct {
 	{ "ignoredhook", &advice_ignored_hook },
 	{ "waitingforeditor", &advice_waiting_for_editor },
 	{ "graftfiledeprecated", &advice_graft_file_deprecated },
+	{ "checkoutambiguousremotebranchname", &advice_checkout_ambiguous_remote_branch_name },
 
 	/* make this an alias for backward compatibility */
 	{ "pushnonfastforward", &advice_push_update_rejected }
diff --git a/advice.h b/advice.h
index 9f5064e82a..4d11d51d43 100644
--- a/advice.h
+++ b/advice.h
@@ -22,6 +22,7 @@ extern int advice_add_embedded_repo;
 extern int advice_ignored_hook;
 extern int advice_waiting_for_editor;
 extern int advice_graft_file_deprecated;
+extern int advice_checkout_ambiguous_remote_branch_name;
 
 int git_default_advice_config(const char *var, const char *value);
 __attribute__((format (printf, 1, 2)))
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 423e056acd..710369a60a 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -22,6 +22,7 @@
 #include "resolve-undo.h"
 #include "submodule-config.h"
 #include "submodule.h"
+#include "advice.h"
 
 static const char * const checkout_usage[] = {
 	N_("git checkout [<options>] <branch>"),
@@ -1269,6 +1270,16 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	if (opts.patch_mode || opts.pathspec.nr) {
 		int ret = checkout_paths(&opts, new_branch_info.name,
 					 &dwim_remotes_matched);
+		if (ret && dwim_remotes_matched > 1 &&
+		    advice_checkout_ambiguous_remote_branch_name)
+			advise(_("The argument '%s' matched more than one remote tracking branch.\n"
+				 "We found %d remotes with a reference that matched. So we fell back\n"
+				 "on trying to resolve the argument as a path, but failed there too!\n"
+				 "\n"
+				 "Perhaps you meant fully qualify the branch name? E.g. origin/<name>\n"
+				 "instead of <name>?"),
+			       argv[0],
+			       dwim_remotes_matched);
 		return ret;
 	} else {
 		return checkout_branch(&opts, &new_branch_info);
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 29c1eada17..14735f5bb8 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -77,6 +77,20 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	status_uno_is_clean
 '
 
+test_expect_success 'checkout of branch from multiple remotes fails with advice' '
+	git checkout -B master &&
+	test_might_fail git branch -D foo &&
+	test_must_fail git checkout foo 2>stderr &&
+	test_branch master &&
+	status_uno_is_clean &&
+	test_i18ngrep "^hint: " stderr &&
+	test_must_fail git -c advice.checkoutAmbiguousRemoteBranchName=false \
+		checkout foo 2>stderr &&
+	test_branch master &&
+	status_uno_is_clean &&
+	test_i18ngrep ! "^hint: " stderr
+'
+
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	git checkout -B master &&
 	test_might_fail git branch -D bar &&

diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 3e5ac81bd2..ed32828105 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -23,6 +23,12 @@ test_branch_upstream () {
 	test_cmp expect.upstream actual.upstream
 }
 
+status_uno_is_clean() {
+	>status.expect &&
+	git status -uno --porcelain >status.actual &&
+	test_cmp status.expect status.actual
+}
+
 test_expect_success 'setup' '
 	test_commit my_master &&
 	git init repo_a &&
@@ -55,6 +61,7 @@ test_expect_success 'checkout of non-existing branch fails' '
 	test_might_fail git branch -D xyzzy &&
 
 	test_must_fail git checkout xyzzy &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/xyzzy &&
 	test_branch master
 '
@@ -64,6 +71,7 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_might_fail git branch -D foo &&
 
 	test_must_fail git checkout foo &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/foo &&
 	test_branch master
 '
@@ -73,6 +81,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	test_might_fail git branch -D bar &&
 
 	git checkout bar &&
+	status_uno_is_clean &&
 	test_branch bar &&
 	test_cmp_rev remotes/repo_a/bar HEAD &&
 	test_branch_upstream bar repo_a bar
@@ -83,6 +92,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #2' '
 	test_might_fail git branch -D baz &&
 
 	git checkout baz &&
+	status_uno_is_clean &&
 	test_branch baz &&
 	test_cmp_rev remotes/other_b/baz HEAD &&
 	test_branch_upstream baz repo_b baz
@@ -90,6 +100,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #2' '
 
 test_expect_success '--no-guess suppresses branch auto-vivification' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D bar &&
 
 	test_must_fail git checkout --no-guess bar &&
@@ -99,6 +110,7 @@ test_expect_success '--no-guess suppresses branch auto-vivification' '
 
 test_expect_success 'setup more remotes with unconventional refspecs' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	git init repo_c &&
 	(
 		cd repo_c &&
@@ -128,27 +140,33 @@ test_expect_success 'setup more remotes with unconventional refspecs' '
 
 test_expect_success 'checkout of branch from multiple remotes fails #2' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D bar &&
 
 	test_must_fail git checkout bar &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/bar &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch from multiple remotes fails #3' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D baz &&
 
 	test_must_fail git checkout baz &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/baz &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch from a single remote succeeds #3' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	git checkout spam &&
+	status_uno_is_clean &&
 	test_branch spam &&
 	test_cmp_rev refs/remotes/extra_dir/repo_c/extra_dir/spam HEAD &&
 	test_branch_upstream spam repo_c spam
@@ -156,9 +174,11 @@ test_expect_success 'checkout of branch from a single remote succeeds #3' '
 
 test_expect_success 'checkout of branch from a single remote succeeds #4' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D eggs &&
 
 	git checkout eggs &&
+	status_uno_is_clean &&
 	test_branch eggs &&
 	test_cmp_rev refs/repo_d/eggs HEAD &&
 	test_branch_upstream eggs repo_d eggs
@@ -166,32 +186,38 @@ test_expect_success 'checkout of branch from a single remote succeeds #4' '
 
 test_expect_success 'checkout of branch with a file having the same name fails' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	test_must_fail git checkout spam &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/spam &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch with a file in subdir having the same name fails' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	mkdir sub &&
 	mv spam sub/spam &&
 	test_must_fail git -C sub checkout spam &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/spam &&
 	test_branch master
 '
 
 test_expect_success 'checkout <branch> -- succeeds, even if a file with the same name exists' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	git checkout spam -- &&
+	status_uno_is_clean &&
 	test_branch spam &&
 	test_cmp_rev refs/remotes/extra_dir/repo_c/extra_dir/spam HEAD &&
 	test_branch_upstream spam repo_c spam
@@ -200,6 +226,7 @@ test_expect_success 'checkout <branch> -- succeeds, even if a file with the same
 test_expect_success 'loosely defined local base branch is reported correctly' '
 
 	git checkout master &&
+	status_uno_is_clean &&
 	git branch strict &&
 	git branch loose &&
 	git commit --allow-empty -m "a bit more" &&
@@ -210,7 +237,9 @@ test_expect_success 'loosely defined local base branch is reported correctly' '
 	test_config branch.loose.merge master &&
 
 	git checkout strict | sed -e "s/strict/BRANCHNAME/g" >expect &&
+	status_uno_is_clean &&
 	git checkout loose | sed -e "s/loose/BRANCHNAME/g" >actual &&
+	status_uno_is_clean &&
 
 	test_cmp expect actual
 '

diff --git a/checkout.h b/checkout.h
index 9980711179..4cd4cd1c23 100644
--- a/checkout.h
+++ b/checkout.h
@@ -8,6 +8,7 @@
  * tracking branch.  Return the name of the remote if such a branch
  * exists, NULL otherwise.
  */
-extern const char *unique_tracking_name(const char *name, struct object_id *oid);
+extern const char *unique_tracking_name(const char *name,
+					struct object_id *oid);
 
 #endif /* CHECKOUT_H */

diff --git a/checkout.c b/checkout.c
index bdefc888ba..80e430cda8 100644
--- a/checkout.c
+++ b/checkout.c
@@ -10,6 +10,8 @@ struct tracking_name_data {
 	int unique;
 };
 
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 1 }
+
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
 	struct tracking_name_data *cb = cb_data;
@@ -32,7 +34,7 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 
 const char *unique_tracking_name(const char *name, struct object_id *oid)
 {
-	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
+	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);

diff --git a/checkout.c b/checkout.c
index 80e430cda8..7662a39a62 100644
--- a/checkout.c
+++ b/checkout.c
@@ -7,10 +7,10 @@ struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
-	int unique;
+	int num_matches;
 };
 
-#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 1 }
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0 }
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
@@ -23,9 +23,9 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		free(query.dst);
 		return 0;
 	}
+	cb->num_matches++;
 	if (cb->dst_ref) {
 		free(query.dst);
-		cb->unique = 0;
 		return 0;
 	}
 	cb->dst_ref = query.dst;
@@ -39,7 +39,7 @@ const char *unique_tracking_name(const char *name, struct object_id *oid)
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	free(cb_data.src_ref);
-	if (cb_data.unique)
+	if (cb_data.num_matches == 1)
 		return cb_data.dst_ref;
 	free(cb_data.dst_ref);
 	return NULL;

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 72457fb7d5..8c93c55cbc 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1265,8 +1265,10 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	}
 
 	UNLEAK(opts);
-	if (opts.patch_mode || opts.pathspec.nr)
-		return checkout_paths(&opts, new_branch_info.name);
-	else
+	if (opts.patch_mode || opts.pathspec.nr) {
+		int ret = checkout_paths(&opts, new_branch_info.name);
+		return ret;
+	} else {
 		return checkout_branch(&opts, &new_branch_info);
+	}
 }

builtin/checkout.c, builtin/worktree.c, checkout.c, checkout.h

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 2e1d2376d2..72457fb7d5 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -878,7 +878,8 @@ static int parse_branchname_arg(int argc, const char **argv,
 				int dwim_new_local_branch_ok,
 				struct branch_info *new_branch_info,
 				struct checkout_opts *opts,
-				struct object_id *rev)
+				struct object_id *rev,
+				int *dwim_remotes_matched)
 {
 	struct tree **source_tree = &opts->source_tree;
 	const char **new_branch = &opts->new_branch;
@@ -972,7 +973,8 @@ static int parse_branchname_arg(int argc, const char **argv,
 			recover_with_dwim = 0;
 
 		if (recover_with_dwim) {
-			const char *remote = unique_tracking_name(arg, rev);
+			const char *remote = unique_tracking_name(arg, rev,
+								  dwim_remotes_matched);
 			if (remote) {
 				*new_branch = arg;
 				arg = remote;
@@ -1109,6 +1111,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	struct branch_info new_branch_info;
 	char *conflict_style = NULL;
 	int dwim_new_local_branch = 1;
+	int dwim_remotes_matched = 0;
 	struct option options[] = {
 		OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
 		OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
@@ -1219,7 +1222,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 			opts.track == BRANCH_TRACK_UNSPECIFIED &&
 			!opts.new_branch;
 		int n = parse_branchname_arg(argc, argv, dwim_ok,
-					     &new_branch_info, &opts, &rev);
+					     &new_branch_info, &opts, &rev,
+					     &dwim_remotes_matched);
 		argv += n;
 		argc -= n;
 	}
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 5c7d2bb180..a763dbdccb 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -412,7 +412,7 @@ static const char *dwim_branch(const char *path, const char **new_branch)
 	if (guess_remote) {
 		struct object_id oid;
 		const char *remote =
-			unique_tracking_name(*new_branch, &oid);
+			unique_tracking_name(*new_branch, &oid, NULL);
 		return remote;
 	}
 	return NULL;
@@ -484,7 +484,7 @@ static int add(int ac, const char **av, const char *prefix)
 
 		commit = lookup_commit_reference_by_name(branch);
 		if (!commit) {
-			remote = unique_tracking_name(branch, &oid);
+			remote = unique_tracking_name(branch, &oid, NULL);
 			if (remote) {
 				new_branch = branch;
 				branch = remote;
diff --git a/checkout.c b/checkout.c
index 7662a39a62..ee3a7e9c05 100644
--- a/checkout.c
+++ b/checkout.c
@@ -32,12 +32,15 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 	return 0;
 }
 
-const char *unique_tracking_name(const char *name, struct object_id *oid)
+const char *unique_tracking_name(const char *name, struct object_id *oid,
+				 int *dwim_remotes_matched)
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
+	if (dwim_remotes_matched)
+		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
 	if (cb_data.num_matches == 1)
 		return cb_data.dst_ref;
diff --git a/checkout.h b/checkout.h
index 4cd4cd1c23..6b2073310c 100644
--- a/checkout.h
+++ b/checkout.h
@@ -9,6 +9,7 @@
  * exists, NULL otherwise.
  */
 extern const char *unique_tracking_name(const char *name,
-					struct object_id *oid);
+					struct object_id *oid,
+					int *dwim_remotes_matched);
 
 #endif /* CHECKOUT_H */

Documentation/config.txt, Documentation/git-checkout.txt, Documentation/git-worktree.txt, builtin/checkout.c, checkout.c, t/t2024-checkout-dwim.sh, t/t2025-worktree-add.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index dfc0413a84..aef2769211 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -350,7 +350,10 @@ advice.*::
 		remote tracking branch on more than one remote in
 		situations where an unambiguous argument would have
 		otherwise caused a remote-tracking branch to be
-		checked out.
+		checked out. See the `checkout.defaultRemote`
+		configuration variable for how to set a given remote
+		to used by default in some situations where this
+		advice would be printed.
 	amWorkDir::
 		Advice that shows the location of the patch file when
 		linkgit:git-am[1] fails to apply it.
@@ -1105,6 +1108,22 @@ browser.<tool>.path::
 	browse HTML help (see `-w` option in linkgit:git-help[1]) or a
 	working repository in gitweb (see linkgit:git-instaweb[1]).
 
+checkout.defaultRemote::
+	When you run 'git checkout <something>' and only have one
+	remote, it may implicitly fall back on checking out and
+	tracking e.g. 'origin/<something>'. This stops working as soon
+	as you have more than one remote with a '<something>'
+	reference. This setting allows for setting the name of a
+	preferred remote that should always win when it comes to
+	disambiguation. The typical use-case is to set this to
+	`origin`.
++
+Currently this is used by linkgit:git-checkout[1] when 'git checkout
+<something>' will checkout the '<something>' branch on another remote,
+and by linkgit:git-worktree[1] when 'git worktree add' refers to a
+remote branch. This setting might be used for other checkout-like
+commands or functionality in the future.
+
 clean.requireForce::
 	A boolean to make git-clean do nothing unless given -f,
 	-i or -n.   Defaults to true.
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index ca5fc9c798..9db02928c4 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -38,6 +38,15 @@ equivalent to
 $ git checkout -b <branch> --track <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes and one of them is named by
+the `checkout.defaultRemote` configuration variable, we'll use that
+one for the purposes of disambiguation, even if the `<branch>` isn't
+unique across all remotes. Set it to
+e.g. `checkout.defaultRemote=origin` to always checkout remote
+branches from there if `<branch>` is ambiguous but exists on the
+'origin' remote. See also `checkout.defaultRemote` in
+linkgit:git-config[1].
++
 You could omit <branch>, in which case the command degenerates to
 "check out the current branch", which is a glorified no-op with
 rather expensive side-effects to show only the tracking information,
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index afc6576a14..9c26be40f4 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -60,6 +60,15 @@ with a matching name, treat as equivalent to:
 $ git worktree add --track -b <branch> <path> <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes and one of them is named by
+the `checkout.defaultRemote` configuration variable, we'll use that
+one for the purposes of disambiguation, even if the `<branch>` isn't
+unique across all remotes. Set it to
+e.g. `checkout.defaultRemote=origin` to always checkout remote
+branches from there if `<branch>` is ambiguous but exists on the
+'origin' remote. See also `checkout.defaultRemote` in
+linkgit:git-config[1].
++
 If `<commit-ish>` is omitted and neither `-b` nor `-B` nor `--detach` used,
 then, as a convenience, the new worktree is associated with a branch
 (call it `<branch>`) named after `$(basename <path>)`.  If `<branch>`
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 4dfb8f1535..b78481dead 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -912,8 +912,10 @@ static int parse_branchname_arg(int argc, const char **argv,
 	 *   (b) If <something> is _not_ a commit, either "--" is present
 	 *       or <something> is not a path, no -t or -b was given, and
 	 *       and there is a tracking branch whose name is <something>
-	 *       in one and only one remote, then this is a short-hand to
-	 *       fork local <something> from that remote-tracking branch.
+	 *       in one and only one remote (or if the branch exists on the
+	 *       remote named in checkout.defaultRemote), then this is a
+	 *       short-hand to fork local <something> from that
+	 *       remote-tracking branch.
 	 *
 	 *   (c) Otherwise, if "--" is present, treat it like case (1).
 	 *
@@ -1277,7 +1279,11 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 				 "If you meant to check out a remote tracking branch on e.g. 'origin'\n"
 				 "you can do so by fully-qualifying the name with the --track option:\n"
 				 "\n"
-				 "    git checkout --track origin/<name>"),
+				 "    git checkout --track origin/<name>\n"
+				 "\n"
+				 "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
+				 "one remote, e.g. the 'origin' remote, consider setting\n"
+				 "checkout.defaultRemote=origin in your config."),
 			       argv[0],
 			       dwim_remotes_matched);
 		return ret;
diff --git a/checkout.c b/checkout.c
index ee3a7e9c05..c72e9f9773 100644
--- a/checkout.c
+++ b/checkout.c
@@ -2,15 +2,19 @@
 #include "remote.h"
 #include "refspec.h"
 #include "checkout.h"
+#include "config.h"
 
 struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
 	int num_matches;
+	const char *default_remote;
+	char *default_dst_ref;
+	struct object_id *default_dst_oid;
 };
 
-#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0 }
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0, NULL, NULL, NULL }
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
@@ -24,6 +28,12 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		return 0;
 	}
 	cb->num_matches++;
+	if (cb->default_remote && !strcmp(remote->name, cb->default_remote)) {
+		struct object_id *dst = xmalloc(sizeof(*cb->default_dst_oid));
+		cb->default_dst_ref = xstrdup(query.dst);
+		oidcpy(dst, cb->dst_oid);
+		cb->default_dst_oid = dst;
+	}
 	if (cb->dst_ref) {
 		free(query.dst);
 		return 0;
@@ -36,14 +46,26 @@ const char *unique_tracking_name(const char *name, struct object_id *oid,
 				 int *dwim_remotes_matched)
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
+	const char *default_remote = NULL;
+	if (!git_config_get_string_const("checkout.defaultremote", &default_remote))
+		cb_data.default_remote = default_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	if (dwim_remotes_matched)
 		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
-	if (cb_data.num_matches == 1)
+	free((char *)default_remote);
+	if (cb_data.num_matches == 1) {
+		free(cb_data.default_dst_ref);
+		free(cb_data.default_dst_oid);
 		return cb_data.dst_ref;
+	}
 	free(cb_data.dst_ref);
+	if (cb_data.default_dst_ref) {
+		oidcpy(oid, cb_data.default_dst_oid);
+		free(cb_data.default_dst_oid);
+		return cb_data.default_dst_ref;
+	}
 	return NULL;
 }
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index fef263a858..1495c248a7 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -87,7 +87,23 @@ test_expect_success 'checkout of branch from multiple remotes fails with advice'
 		checkout foo 2>stderr &&
 	test_branch master &&
 	status_uno_is_clean &&
-	test_i18ngrep ! "^hint: " stderr
+	test_i18ngrep ! "^hint: " stderr &&
+	# Make sure the likes of checkout -p don not print this hint
+	git checkout -p foo 2>stderr &&
+	test_i18ngrep ! "^hint: " stderr &&
+	status_uno_is_clean
+'
+
+test_expect_success 'checkout of branch from multiple remotes succeeds with checkout.defaultRemote #1' '
+	git checkout -B master &&
+	status_uno_is_clean &&
+	test_might_fail git branch -D foo &&
+
+	git -c checkout.defaultRemote=repo_a checkout foo &&
+	status_uno_is_clean &&
+	test_branch foo &&
+	test_cmp_rev remotes/repo_a/foo HEAD &&
+	test_branch_upstream foo repo_a foo
 '
 
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index d2e49f7632..be6e093142 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -402,6 +402,27 @@ test_expect_success '"add" <path> <branch> dwims' '
 	)
 '
 
+test_expect_success '"add" <path> <branch> dwims with checkout.defaultRemote' '
+	test_when_finished rm -rf repo_upstream repo_dwim foo &&
+	setup_remote_repo repo_upstream repo_dwim &&
+	git init repo_dwim &&
+	(
+		cd repo_dwim &&
+		git remote add repo_upstream2 ../repo_upstream &&
+		git fetch repo_upstream2 &&
+		test_must_fail git worktree add ../foo foo &&
+		git -c checkout.defaultRemote=repo_upstream worktree add ../foo foo &&
+		>status.expect &&
+		git status -uno --porcelain >status.actual &&
+		test_cmp status.expect status.actual
+	) &&
+	(
+		cd foo &&
+		test_branch_upstream foo repo_upstream foo &&
+		test_cmp_rev refs/remotes/repo_upstream/foo refs/heads/foo
+	)
+'
+
 test_expect_success 'git worktree add does not match remote' '
 	test_when_finished rm -rf repo_a repo_b foo &&
 	setup_remote_repo repo_a repo_b &&

Documentation/config.txt, advice.c, advice.h, builtin/checkout.c, t/t2024-checkout-dwim.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index ab641bf5a9..dfc0413a84 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -344,6 +344,13 @@ advice.*::
 		Advice shown when you used linkgit:git-checkout[1] to
 		move to the detach HEAD state, to instruct how to create
 		a local branch after the fact.
+	checkoutAmbiguousRemoteBranchName::
+		Advice shown when the argument to
+		linkgit:git-checkout[1] ambiguously resolves to a
+		remote tracking branch on more than one remote in
+		situations where an unambiguous argument would have
+		otherwise caused a remote-tracking branch to be
+		checked out.
 	amWorkDir::
 		Advice that shows the location of the patch file when
 		linkgit:git-am[1] fails to apply it.
diff --git a/advice.c b/advice.c
index 370a56d054..75e7dede90 100644
--- a/advice.c
+++ b/advice.c
@@ -21,6 +21,7 @@ int advice_add_embedded_repo = 1;
 int advice_ignored_hook = 1;
 int advice_waiting_for_editor = 1;
 int advice_graft_file_deprecated = 1;
+int advice_checkout_ambiguous_remote_branch_name = 1;
 
 static int advice_use_color = -1;
 static char advice_colors[][COLOR_MAXLEN] = {
@@ -72,6 +73,7 @@ static struct {
 	{ "ignoredhook", &advice_ignored_hook },
 	{ "waitingforeditor", &advice_waiting_for_editor },
 	{ "graftfiledeprecated", &advice_graft_file_deprecated },
+	{ "checkoutambiguousremotebranchname", &advice_checkout_ambiguous_remote_branch_name },
 
 	/* make this an alias for backward compatibility */
 	{ "pushnonfastforward", &advice_push_update_rejected }
diff --git a/advice.h b/advice.h
index 9f5064e82a..4d11d51d43 100644
--- a/advice.h
+++ b/advice.h
@@ -22,6 +22,7 @@ extern int advice_add_embedded_repo;
 extern int advice_ignored_hook;
 extern int advice_waiting_for_editor;
 extern int advice_graft_file_deprecated;
+extern int advice_checkout_ambiguous_remote_branch_name;
 
 int git_default_advice_config(const char *var, const char *value);
 __attribute__((format (printf, 1, 2)))
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 8c93c55cbc..4dfb8f1535 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -22,6 +22,7 @@
 #include "resolve-undo.h"
 #include "submodule-config.h"
 #include "submodule.h"
+#include "advice.h"
 
 static const char * const checkout_usage[] = {
 	N_("git checkout [<options>] <branch>"),
@@ -1267,6 +1268,18 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	UNLEAK(opts);
 	if (opts.patch_mode || opts.pathspec.nr) {
 		int ret = checkout_paths(&opts, new_branch_info.name);
+		if (ret && dwim_remotes_matched > 1 &&
+		    advice_checkout_ambiguous_remote_branch_name)
+			advise(_("The argument '%s' matched more than one remote tracking branch.\n"
+				 "We found %d remotes with a reference that matched. So we fell back\n"
+				 "on trying to resolve the argument as a path, but failed there too!\n"
+				 "\n"
+				 "If you meant to check out a remote tracking branch on e.g. 'origin'\n"
+				 "you can do so by fully-qualifying the name with the --track option:\n"
+				 "\n"
+				 "    git checkout --track origin/<name>"),
+			       argv[0],
+			       dwim_remotes_matched);
 		return ret;
 	} else {
 		return checkout_branch(&opts, &new_branch_info);
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index ed32828105..fef263a858 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -76,6 +76,20 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_branch master
 '
 
+test_expect_success 'checkout of branch from multiple remotes fails with advice' '
+	git checkout -B master &&
+	test_might_fail git branch -D foo &&
+	test_must_fail git checkout foo 2>stderr &&
+	test_branch master &&
+	status_uno_is_clean &&
+	test_i18ngrep "^hint: " stderr &&
+	test_must_fail git -c advice.checkoutAmbiguousRemoteBranchName=false \
+		checkout foo 2>stderr &&
+	test_branch master &&
+	status_uno_is_clean &&
+	test_i18ngrep ! "^hint: " stderr
+'
+
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	git checkout -B master &&
 	test_might_fail git branch -D bar &&

diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 3e5ac81bd2..ed32828105 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -23,6 +23,12 @@ test_branch_upstream () {
 	test_cmp expect.upstream actual.upstream
 }
 
+status_uno_is_clean() {
+	>status.expect &&
+	git status -uno --porcelain >status.actual &&
+	test_cmp status.expect status.actual
+}
+
 test_expect_success 'setup' '
 	test_commit my_master &&
 	git init repo_a &&
@@ -55,6 +61,7 @@ test_expect_success 'checkout of non-existing branch fails' '
 	test_might_fail git branch -D xyzzy &&
 
 	test_must_fail git checkout xyzzy &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/xyzzy &&
 	test_branch master
 '
@@ -64,6 +71,7 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_might_fail git branch -D foo &&
 
 	test_must_fail git checkout foo &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/foo &&
 	test_branch master
 '
@@ -73,6 +81,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	test_might_fail git branch -D bar &&
 
 	git checkout bar &&
+	status_uno_is_clean &&
 	test_branch bar &&
 	test_cmp_rev remotes/repo_a/bar HEAD &&
 	test_branch_upstream bar repo_a bar
@@ -83,6 +92,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #2' '
 	test_might_fail git branch -D baz &&
 
 	git checkout baz &&
+	status_uno_is_clean &&
 	test_branch baz &&
 	test_cmp_rev remotes/other_b/baz HEAD &&
 	test_branch_upstream baz repo_b baz
@@ -90,6 +100,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #2' '
 
 test_expect_success '--no-guess suppresses branch auto-vivification' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D bar &&
 
 	test_must_fail git checkout --no-guess bar &&
@@ -99,6 +110,7 @@ test_expect_success '--no-guess suppresses branch auto-vivification' '
 
 test_expect_success 'setup more remotes with unconventional refspecs' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	git init repo_c &&
 	(
 		cd repo_c &&
@@ -128,27 +140,33 @@ test_expect_success 'setup more remotes with unconventional refspecs' '
 
 test_expect_success 'checkout of branch from multiple remotes fails #2' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D bar &&
 
 	test_must_fail git checkout bar &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/bar &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch from multiple remotes fails #3' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D baz &&
 
 	test_must_fail git checkout baz &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/baz &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch from a single remote succeeds #3' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	git checkout spam &&
+	status_uno_is_clean &&
 	test_branch spam &&
 	test_cmp_rev refs/remotes/extra_dir/repo_c/extra_dir/spam HEAD &&
 	test_branch_upstream spam repo_c spam
@@ -156,9 +174,11 @@ test_expect_success 'checkout of branch from a single remote succeeds #3' '
 
 test_expect_success 'checkout of branch from a single remote succeeds #4' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D eggs &&
 
 	git checkout eggs &&
+	status_uno_is_clean &&
 	test_branch eggs &&
 	test_cmp_rev refs/repo_d/eggs HEAD &&
 	test_branch_upstream eggs repo_d eggs
@@ -166,32 +186,38 @@ test_expect_success 'checkout of branch from a single remote succeeds #4' '
 
 test_expect_success 'checkout of branch with a file having the same name fails' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	test_must_fail git checkout spam &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/spam &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch with a file in subdir having the same name fails' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	mkdir sub &&
 	mv spam sub/spam &&
 	test_must_fail git -C sub checkout spam &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/spam &&
 	test_branch master
 '
 
 test_expect_success 'checkout <branch> -- succeeds, even if a file with the same name exists' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	git checkout spam -- &&
+	status_uno_is_clean &&
 	test_branch spam &&
 	test_cmp_rev refs/remotes/extra_dir/repo_c/extra_dir/spam HEAD &&
 	test_branch_upstream spam repo_c spam
@@ -200,6 +226,7 @@ test_expect_success 'checkout <branch> -- succeeds, even if a file with the same
 test_expect_success 'loosely defined local base branch is reported correctly' '
 
 	git checkout master &&
+	status_uno_is_clean &&
 	git branch strict &&
 	git branch loose &&
 	git commit --allow-empty -m "a bit more" &&
@@ -210,7 +237,9 @@ test_expect_success 'loosely defined local base branch is reported correctly' '
 	test_config branch.loose.merge master &&
 
 	git checkout strict | sed -e "s/strict/BRANCHNAME/g" >expect &&
+	status_uno_is_clean &&
 	git checkout loose | sed -e "s/loose/BRANCHNAME/g" >actual &&
+	status_uno_is_clean &&
 
 	test_cmp expect actual
 '

diff --git a/checkout.h b/checkout.h
index 9980711179..4cd4cd1c23 100644
--- a/checkout.h
+++ b/checkout.h
@@ -8,6 +8,7 @@
  * tracking branch.  Return the name of the remote if such a branch
  * exists, NULL otherwise.
  */
-extern const char *unique_tracking_name(const char *name, struct object_id *oid);
+extern const char *unique_tracking_name(const char *name,
+					struct object_id *oid);
 
 #endif /* CHECKOUT_H */

diff --git a/checkout.c b/checkout.c
index bdefc888ba..80e430cda8 100644
--- a/checkout.c
+++ b/checkout.c
@@ -10,6 +10,8 @@ struct tracking_name_data {
 	int unique;
 };
 
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 1 }
+
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
 	struct tracking_name_data *cb = cb_data;
@@ -32,7 +34,7 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 
 const char *unique_tracking_name(const char *name, struct object_id *oid)
 {
-	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
+	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);

diff --git a/checkout.c b/checkout.c
index 80e430cda8..7662a39a62 100644
--- a/checkout.c
+++ b/checkout.c
@@ -7,10 +7,10 @@ struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
-	int unique;
+	int num_matches;
 };
 
-#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 1 }
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0 }
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
@@ -23,9 +23,9 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		free(query.dst);
 		return 0;
 	}
+	cb->num_matches++;
 	if (cb->dst_ref) {
 		free(query.dst);
-		cb->unique = 0;
 		return 0;
 	}
 	cb->dst_ref = query.dst;
@@ -39,7 +39,7 @@ const char *unique_tracking_name(const char *name, struct object_id *oid)
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	free(cb_data.src_ref);
-	if (cb_data.unique)
+	if (cb_data.num_matches == 1)
 		return cb_data.dst_ref;
 	free(cb_data.dst_ref);
 	return NULL;

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 72457fb7d5..8c93c55cbc 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1265,8 +1265,10 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	}
 
 	UNLEAK(opts);
-	if (opts.patch_mode || opts.pathspec.nr)
-		return checkout_paths(&opts, new_branch_info.name);
-	else
+	if (opts.patch_mode || opts.pathspec.nr) {
+		int ret = checkout_paths(&opts, new_branch_info.name);
+		return ret;
+	} else {
 		return checkout_branch(&opts, &new_branch_info);
+	}
 }

builtin/checkout.c, builtin/worktree.c, checkout.c, checkout.h

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 2e1d2376d2..72457fb7d5 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -878,7 +878,8 @@ static int parse_branchname_arg(int argc, const char **argv,
 				int dwim_new_local_branch_ok,
 				struct branch_info *new_branch_info,
 				struct checkout_opts *opts,
-				struct object_id *rev)
+				struct object_id *rev,
+				int *dwim_remotes_matched)
 {
 	struct tree **source_tree = &opts->source_tree;
 	const char **new_branch = &opts->new_branch;
@@ -972,7 +973,8 @@ static int parse_branchname_arg(int argc, const char **argv,
 			recover_with_dwim = 0;
 
 		if (recover_with_dwim) {
-			const char *remote = unique_tracking_name(arg, rev);
+			const char *remote = unique_tracking_name(arg, rev,
+								  dwim_remotes_matched);
 			if (remote) {
 				*new_branch = arg;
 				arg = remote;
@@ -1109,6 +1111,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	struct branch_info new_branch_info;
 	char *conflict_style = NULL;
 	int dwim_new_local_branch = 1;
+	int dwim_remotes_matched = 0;
 	struct option options[] = {
 		OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
 		OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
@@ -1219,7 +1222,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 			opts.track == BRANCH_TRACK_UNSPECIFIED &&
 			!opts.new_branch;
 		int n = parse_branchname_arg(argc, argv, dwim_ok,
-					     &new_branch_info, &opts, &rev);
+					     &new_branch_info, &opts, &rev,
+					     &dwim_remotes_matched);
 		argv += n;
 		argc -= n;
 	}
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 5c7d2bb180..a763dbdccb 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -412,7 +412,7 @@ static const char *dwim_branch(const char *path, const char **new_branch)
 	if (guess_remote) {
 		struct object_id oid;
 		const char *remote =
-			unique_tracking_name(*new_branch, &oid);
+			unique_tracking_name(*new_branch, &oid, NULL);
 		return remote;
 	}
 	return NULL;
@@ -484,7 +484,7 @@ static int add(int ac, const char **av, const char *prefix)
 
 		commit = lookup_commit_reference_by_name(branch);
 		if (!commit) {
-			remote = unique_tracking_name(branch, &oid);
+			remote = unique_tracking_name(branch, &oid, NULL);
 			if (remote) {
 				new_branch = branch;
 				branch = remote;
diff --git a/checkout.c b/checkout.c
index 7662a39a62..ee3a7e9c05 100644
--- a/checkout.c
+++ b/checkout.c
@@ -32,12 +32,15 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 	return 0;
 }
 
-const char *unique_tracking_name(const char *name, struct object_id *oid)
+const char *unique_tracking_name(const char *name, struct object_id *oid,
+				 int *dwim_remotes_matched)
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
+	if (dwim_remotes_matched)
+		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
 	if (cb_data.num_matches == 1)
 		return cb_data.dst_ref;
diff --git a/checkout.h b/checkout.h
index 4cd4cd1c23..6b2073310c 100644
--- a/checkout.h
+++ b/checkout.h
@@ -9,6 +9,7 @@
  * exists, NULL otherwise.
  */
 extern const char *unique_tracking_name(const char *name,
-					struct object_id *oid);
+					struct object_id *oid,
+					int *dwim_remotes_matched);
 
 #endif /* CHECKOUT_H */

Documentation/config.txt, advice.c, advice.h, builtin/checkout.c, t/t2024-checkout-dwim.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index ab641bf5a9..dfc0413a84 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -344,6 +344,13 @@ advice.*::
 		Advice shown when you used linkgit:git-checkout[1] to
 		move to the detach HEAD state, to instruct how to create
 		a local branch after the fact.
+	checkoutAmbiguousRemoteBranchName::
+		Advice shown when the argument to
+		linkgit:git-checkout[1] ambiguously resolves to a
+		remote tracking branch on more than one remote in
+		situations where an unambiguous argument would have
+		otherwise caused a remote-tracking branch to be
+		checked out.
 	amWorkDir::
 		Advice that shows the location of the patch file when
 		linkgit:git-am[1] fails to apply it.
diff --git a/advice.c b/advice.c
index 370a56d054..75e7dede90 100644
--- a/advice.c
+++ b/advice.c
@@ -21,6 +21,7 @@ int advice_add_embedded_repo = 1;
 int advice_ignored_hook = 1;
 int advice_waiting_for_editor = 1;
 int advice_graft_file_deprecated = 1;
+int advice_checkout_ambiguous_remote_branch_name = 1;
 
 static int advice_use_color = -1;
 static char advice_colors[][COLOR_MAXLEN] = {
@@ -72,6 +73,7 @@ static struct {
 	{ "ignoredhook", &advice_ignored_hook },
 	{ "waitingforeditor", &advice_waiting_for_editor },
 	{ "graftfiledeprecated", &advice_graft_file_deprecated },
+	{ "checkoutambiguousremotebranchname", &advice_checkout_ambiguous_remote_branch_name },
 
 	/* make this an alias for backward compatibility */
 	{ "pushnonfastforward", &advice_push_update_rejected }
diff --git a/advice.h b/advice.h
index 9f5064e82a..4d11d51d43 100644
--- a/advice.h
+++ b/advice.h
@@ -22,6 +22,7 @@ extern int advice_add_embedded_repo;
 extern int advice_ignored_hook;
 extern int advice_waiting_for_editor;
 extern int advice_graft_file_deprecated;
+extern int advice_checkout_ambiguous_remote_branch_name;
 
 int git_default_advice_config(const char *var, const char *value);
 __attribute__((format (printf, 1, 2)))
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 8c93c55cbc..baa027455a 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -22,6 +22,7 @@
 #include "resolve-undo.h"
 #include "submodule-config.h"
 #include "submodule.h"
+#include "advice.h"
 
 static const char * const checkout_usage[] = {
 	N_("git checkout [<options>] <branch>"),
@@ -1267,6 +1268,18 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	UNLEAK(opts);
 	if (opts.patch_mode || opts.pathspec.nr) {
 		int ret = checkout_paths(&opts, new_branch_info.name);
+		if (ret && dwim_remotes_matched > 1 &&
+		    advice_checkout_ambiguous_remote_branch_name)
+			advise(_("'%s' matched more than one remote tracking branch.\n"
+				 "We found %d remotes with a reference that matched. So we fell back\n"
+				 "on trying to resolve the argument as a path, but failed there too!\n"
+				 "\n"
+				 "If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
+				 "you can do so by fully qualifying the name with the --track option:\n"
+				 "\n"
+				 "    git checkout --track origin/<name>"),
+			       argv[0],
+			       dwim_remotes_matched);
 		return ret;
 	} else {
 		return checkout_branch(&opts, &new_branch_info);
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index ed32828105..fef263a858 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -76,6 +76,20 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_branch master
 '
 
+test_expect_success 'checkout of branch from multiple remotes fails with advice' '
+	git checkout -B master &&
+	test_might_fail git branch -D foo &&
+	test_must_fail git checkout foo 2>stderr &&
+	test_branch master &&
+	status_uno_is_clean &&
+	test_i18ngrep "^hint: " stderr &&
+	test_must_fail git -c advice.checkoutAmbiguousRemoteBranchName=false \
+		checkout foo 2>stderr &&
+	test_branch master &&
+	status_uno_is_clean &&
+	test_i18ngrep ! "^hint: " stderr
+'
+
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	git checkout -B master &&
 	test_might_fail git branch -D bar &&

Documentation/config.txt, Documentation/git-checkout.txt, Documentation/git-worktree.txt, builtin/checkout.c, checkout.c, t/t2024-checkout-dwim.sh, t/t2025-worktree-add.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index dfc0413a84..aef2769211 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -350,7 +350,10 @@ advice.*::
 		remote tracking branch on more than one remote in
 		situations where an unambiguous argument would have
 		otherwise caused a remote-tracking branch to be
-		checked out.
+		checked out. See the `checkout.defaultRemote`
+		configuration variable for how to set a given remote
+		to used by default in some situations where this
+		advice would be printed.
 	amWorkDir::
 		Advice that shows the location of the patch file when
 		linkgit:git-am[1] fails to apply it.
@@ -1105,6 +1108,22 @@ browser.<tool>.path::
 	browse HTML help (see `-w` option in linkgit:git-help[1]) or a
 	working repository in gitweb (see linkgit:git-instaweb[1]).
 
+checkout.defaultRemote::
+	When you run 'git checkout <something>' and only have one
+	remote, it may implicitly fall back on checking out and
+	tracking e.g. 'origin/<something>'. This stops working as soon
+	as you have more than one remote with a '<something>'
+	reference. This setting allows for setting the name of a
+	preferred remote that should always win when it comes to
+	disambiguation. The typical use-case is to set this to
+	`origin`.
++
+Currently this is used by linkgit:git-checkout[1] when 'git checkout
+<something>' will checkout the '<something>' branch on another remote,
+and by linkgit:git-worktree[1] when 'git worktree add' refers to a
+remote branch. This setting might be used for other checkout-like
+commands or functionality in the future.
+
 clean.requireForce::
 	A boolean to make git-clean do nothing unless given -f,
 	-i or -n.   Defaults to true.
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index ca5fc9c798..9db02928c4 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -38,6 +38,15 @@ equivalent to
 $ git checkout -b <branch> --track <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes and one of them is named by
+the `checkout.defaultRemote` configuration variable, we'll use that
+one for the purposes of disambiguation, even if the `<branch>` isn't
+unique across all remotes. Set it to
+e.g. `checkout.defaultRemote=origin` to always checkout remote
+branches from there if `<branch>` is ambiguous but exists on the
+'origin' remote. See also `checkout.defaultRemote` in
+linkgit:git-config[1].
++
 You could omit <branch>, in which case the command degenerates to
 "check out the current branch", which is a glorified no-op with
 rather expensive side-effects to show only the tracking information,
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index afc6576a14..9c26be40f4 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -60,6 +60,15 @@ with a matching name, treat as equivalent to:
 $ git worktree add --track -b <branch> <path> <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes and one of them is named by
+the `checkout.defaultRemote` configuration variable, we'll use that
+one for the purposes of disambiguation, even if the `<branch>` isn't
+unique across all remotes. Set it to
+e.g. `checkout.defaultRemote=origin` to always checkout remote
+branches from there if `<branch>` is ambiguous but exists on the
+'origin' remote. See also `checkout.defaultRemote` in
+linkgit:git-config[1].
++
 If `<commit-ish>` is omitted and neither `-b` nor `-B` nor `--detach` used,
 then, as a convenience, the new worktree is associated with a branch
 (call it `<branch>`) named after `$(basename <path>)`.  If `<branch>`
diff --git a/builtin/checkout.c b/builtin/checkout.c
index baa027455a..5b357e922a 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -912,8 +912,10 @@ static int parse_branchname_arg(int argc, const char **argv,
 	 *   (b) If <something> is _not_ a commit, either "--" is present
 	 *       or <something> is not a path, no -t or -b was given, and
 	 *       and there is a tracking branch whose name is <something>
-	 *       in one and only one remote, then this is a short-hand to
-	 *       fork local <something> from that remote-tracking branch.
+	 *       in one and only one remote (or if the branch exists on the
+	 *       remote named in checkout.defaultRemote), then this is a
+	 *       short-hand to fork local <something> from that
+	 *       remote-tracking branch.
 	 *
 	 *   (c) Otherwise, if "--" is present, treat it like case (1).
 	 *
@@ -1277,7 +1279,11 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 				 "If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
 				 "you can do so by fully qualifying the name with the --track option:\n"
 				 "\n"
-				 "    git checkout --track origin/<name>"),
+				 "    git checkout --track origin/<name>\n"
+				 "\n"
+				 "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
+				 "one remote, e.g. the 'origin' remote, consider setting\n"
+				 "checkout.defaultRemote=origin in your config."),
 			       argv[0],
 			       dwim_remotes_matched);
 		return ret;
diff --git a/checkout.c b/checkout.c
index ee3a7e9c05..c72e9f9773 100644
--- a/checkout.c
+++ b/checkout.c
@@ -2,15 +2,19 @@
 #include "remote.h"
 #include "refspec.h"
 #include "checkout.h"
+#include "config.h"
 
 struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
 	int num_matches;
+	const char *default_remote;
+	char *default_dst_ref;
+	struct object_id *default_dst_oid;
 };
 
-#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0 }
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0, NULL, NULL, NULL }
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
@@ -24,6 +28,12 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		return 0;
 	}
 	cb->num_matches++;
+	if (cb->default_remote && !strcmp(remote->name, cb->default_remote)) {
+		struct object_id *dst = xmalloc(sizeof(*cb->default_dst_oid));
+		cb->default_dst_ref = xstrdup(query.dst);
+		oidcpy(dst, cb->dst_oid);
+		cb->default_dst_oid = dst;
+	}
 	if (cb->dst_ref) {
 		free(query.dst);
 		return 0;
@@ -36,14 +46,26 @@ const char *unique_tracking_name(const char *name, struct object_id *oid,
 				 int *dwim_remotes_matched)
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
+	const char *default_remote = NULL;
+	if (!git_config_get_string_const("checkout.defaultremote", &default_remote))
+		cb_data.default_remote = default_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	if (dwim_remotes_matched)
 		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
-	if (cb_data.num_matches == 1)
+	free((char *)default_remote);
+	if (cb_data.num_matches == 1) {
+		free(cb_data.default_dst_ref);
+		free(cb_data.default_dst_oid);
 		return cb_data.dst_ref;
+	}
 	free(cb_data.dst_ref);
+	if (cb_data.default_dst_ref) {
+		oidcpy(oid, cb_data.default_dst_oid);
+		free(cb_data.default_dst_oid);
+		return cb_data.default_dst_ref;
+	}
 	return NULL;
 }
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index fef263a858..1495c248a7 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -87,7 +87,23 @@ test_expect_success 'checkout of branch from multiple remotes fails with advice'
 		checkout foo 2>stderr &&
 	test_branch master &&
 	status_uno_is_clean &&
-	test_i18ngrep ! "^hint: " stderr
+	test_i18ngrep ! "^hint: " stderr &&
+	# Make sure the likes of checkout -p don not print this hint
+	git checkout -p foo 2>stderr &&
+	test_i18ngrep ! "^hint: " stderr &&
+	status_uno_is_clean
+'
+
+test_expect_success 'checkout of branch from multiple remotes succeeds with checkout.defaultRemote #1' '
+	git checkout -B master &&
+	status_uno_is_clean &&
+	test_might_fail git branch -D foo &&
+
+	git -c checkout.defaultRemote=repo_a checkout foo &&
+	status_uno_is_clean &&
+	test_branch foo &&
+	test_cmp_rev remotes/repo_a/foo HEAD &&
+	test_branch_upstream foo repo_a foo
 '
 
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index d2e49f7632..be6e093142 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -402,6 +402,27 @@ test_expect_success '"add" <path> <branch> dwims' '
 	)
 '
 
+test_expect_success '"add" <path> <branch> dwims with checkout.defaultRemote' '
+	test_when_finished rm -rf repo_upstream repo_dwim foo &&
+	setup_remote_repo repo_upstream repo_dwim &&
+	git init repo_dwim &&
+	(
+		cd repo_dwim &&
+		git remote add repo_upstream2 ../repo_upstream &&
+		git fetch repo_upstream2 &&
+		test_must_fail git worktree add ../foo foo &&
+		git -c checkout.defaultRemote=repo_upstream worktree add ../foo foo &&
+		>status.expect &&
+		git status -uno --porcelain >status.actual &&
+		test_cmp status.expect status.actual
+	) &&
+	(
+		cd foo &&
+		test_branch_upstream foo repo_upstream foo &&
+		test_cmp_rev refs/remotes/repo_upstream/foo refs/heads/foo
+	)
+'
+
 test_expect_success 'git worktree add does not match remote' '
 	test_when_finished rm -rf repo_a repo_b foo &&
 	setup_remote_repo repo_a repo_b &&

diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 3e5ac81bd2..ed32828105 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -23,6 +23,12 @@ test_branch_upstream () {
 	test_cmp expect.upstream actual.upstream
 }
 
+status_uno_is_clean() {
+	>status.expect &&
+	git status -uno --porcelain >status.actual &&
+	test_cmp status.expect status.actual
+}
+
 test_expect_success 'setup' '
 	test_commit my_master &&
 	git init repo_a &&
@@ -55,6 +61,7 @@ test_expect_success 'checkout of non-existing branch fails' '
 	test_might_fail git branch -D xyzzy &&
 
 	test_must_fail git checkout xyzzy &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/xyzzy &&
 	test_branch master
 '
@@ -64,6 +71,7 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_might_fail git branch -D foo &&
 
 	test_must_fail git checkout foo &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/foo &&
 	test_branch master
 '
@@ -73,6 +81,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	test_might_fail git branch -D bar &&
 
 	git checkout bar &&
+	status_uno_is_clean &&
 	test_branch bar &&
 	test_cmp_rev remotes/repo_a/bar HEAD &&
 	test_branch_upstream bar repo_a bar
@@ -83,6 +92,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #2' '
 	test_might_fail git branch -D baz &&
 
 	git checkout baz &&
+	status_uno_is_clean &&
 	test_branch baz &&
 	test_cmp_rev remotes/other_b/baz HEAD &&
 	test_branch_upstream baz repo_b baz
@@ -90,6 +100,7 @@ test_expect_success 'checkout of branch from a single remote succeeds #2' '
 
 test_expect_success '--no-guess suppresses branch auto-vivification' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D bar &&
 
 	test_must_fail git checkout --no-guess bar &&
@@ -99,6 +110,7 @@ test_expect_success '--no-guess suppresses branch auto-vivification' '
 
 test_expect_success 'setup more remotes with unconventional refspecs' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	git init repo_c &&
 	(
 		cd repo_c &&
@@ -128,27 +140,33 @@ test_expect_success 'setup more remotes with unconventional refspecs' '
 
 test_expect_success 'checkout of branch from multiple remotes fails #2' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D bar &&
 
 	test_must_fail git checkout bar &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/bar &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch from multiple remotes fails #3' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D baz &&
 
 	test_must_fail git checkout baz &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/baz &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch from a single remote succeeds #3' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	git checkout spam &&
+	status_uno_is_clean &&
 	test_branch spam &&
 	test_cmp_rev refs/remotes/extra_dir/repo_c/extra_dir/spam HEAD &&
 	test_branch_upstream spam repo_c spam
@@ -156,9 +174,11 @@ test_expect_success 'checkout of branch from a single remote succeeds #3' '
 
 test_expect_success 'checkout of branch from a single remote succeeds #4' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D eggs &&
 
 	git checkout eggs &&
+	status_uno_is_clean &&
 	test_branch eggs &&
 	test_cmp_rev refs/repo_d/eggs HEAD &&
 	test_branch_upstream eggs repo_d eggs
@@ -166,32 +186,38 @@ test_expect_success 'checkout of branch from a single remote succeeds #4' '
 
 test_expect_success 'checkout of branch with a file having the same name fails' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	test_must_fail git checkout spam &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/spam &&
 	test_branch master
 '
 
 test_expect_success 'checkout of branch with a file in subdir having the same name fails' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	mkdir sub &&
 	mv spam sub/spam &&
 	test_must_fail git -C sub checkout spam &&
+	status_uno_is_clean &&
 	test_must_fail git rev-parse --verify refs/heads/spam &&
 	test_branch master
 '
 
 test_expect_success 'checkout <branch> -- succeeds, even if a file with the same name exists' '
 	git checkout -B master &&
+	status_uno_is_clean &&
 	test_might_fail git branch -D spam &&
 
 	>spam &&
 	git checkout spam -- &&
+	status_uno_is_clean &&
 	test_branch spam &&
 	test_cmp_rev refs/remotes/extra_dir/repo_c/extra_dir/spam HEAD &&
 	test_branch_upstream spam repo_c spam
@@ -200,6 +226,7 @@ test_expect_success 'checkout <branch> -- succeeds, even if a file with the same
 test_expect_success 'loosely defined local base branch is reported correctly' '
 
 	git checkout master &&
+	status_uno_is_clean &&
 	git branch strict &&
 	git branch loose &&
 	git commit --allow-empty -m "a bit more" &&
@@ -210,7 +237,9 @@ test_expect_success 'loosely defined local base branch is reported correctly' '
 	test_config branch.loose.merge master &&
 
 	git checkout strict | sed -e "s/strict/BRANCHNAME/g" >expect &&
+	status_uno_is_clean &&
 	git checkout loose | sed -e "s/loose/BRANCHNAME/g" >actual &&
+	status_uno_is_clean &&
 
 	test_cmp expect actual
 '

t/t0008-ignores.sh, t/t0030-stripspace.sh, t/t0300-credentials.sh, t/t1011-read-tree-sparse-checkout.sh, t/t1306-xdg-files.sh, t/t1403-show-ref.sh, t/t1507-rev-parse-upstream.sh, t/t2024-checkout-dwim.sh, t/t2025-worktree-add.sh, t/t2202-add-addremove.sh, t/t3001-ls-files-others-exclude.sh, t/t3070-wildmatch.sh, t/t3201-branch-contains.sh, t/t3700-add.sh, t/t3910-mac-os-precompose.sh, t/t4010-diff-pathspec.sh, t/t4015-diff-whitespace.sh, t/t4039-diff-assume-unchanged.sh, t/t4200-rerere.sh, t/t4202-log.sh, t/t4210-log-i18n.sh, t/t5310-pack-bitmaps.sh, t/t5313-pack-bounds-checks.sh, t/t5505-remote.sh, t/t5512-ls-remote.sh, t/t5514-fetch-multiple.sh, t/t5533-push-cas.sh, t/t5612-clone-refspec.sh, t/t6000-rev-list-misc.sh, t/t6009-rev-list-parent.sh, t/t6018-rev-list-glob.sh, t/t6019-rev-list-ancestry-path.sh, t/t6022-merge-rename.sh, t/t6060-merge-index.sh, t/t6300-for-each-ref.sh, t/t7004-tag.sh, t/t7006-pager.sh, t/t7030-verify-tag.sh, t/t7063-status-untracked-cache.sh, t/t7102-reset.sh, t/t7106-reset-unborn-branch.sh, t/t7401-submodule-summary.sh, t/t7502-commit.sh, t/t7610-mergetool.sh, t/t7810-grep.sh, t/t9001-send-email.sh, t/t9300-fast-import.sh

diff --git a/t/t0008-ignores.sh b/t/t0008-ignores.sh
index c03f155a35..1744cee5e9 100755
--- a/t/t0008-ignores.sh
+++ b/t/t0008-ignores.sh
@@ -807,10 +807,9 @@ test_expect_success 'trailing whitespace is ignored' '
 	cat >expect <<EOF &&
 whitespace/untracked
 EOF
-	: >err.expect &&
 	git ls-files -o -X ignore whitespace >actual 2>err &&
 	test_cmp expect actual &&
-	test_cmp err.expect err
+	test_must_be_empty err
 '
 
 test_expect_success !MINGW 'quoting allows trailing whitespace' '
@@ -820,10 +819,9 @@ test_expect_success !MINGW 'quoting allows trailing whitespace' '
 	>whitespace/untracked &&
 	echo "whitespace/trailing\\ \\ " >ignore &&
 	echo whitespace/untracked >expect &&
-	: >err.expect &&
 	git ls-files -o -X ignore whitespace >actual 2>err &&
 	test_cmp expect actual &&
-	test_cmp err.expect err
+	test_must_be_empty err
 '
 
 test_expect_success !MINGW,!CYGWIN 'correct handling of backslashes' '
@@ -845,10 +843,9 @@ test_expect_success !MINGW,!CYGWIN 'correct handling of backslashes' '
 	whitespace/trailing 6 \\a\\Z
 	EOF
 	echo whitespace/untracked >expect &&
-	>err.expect &&
 	git ls-files -o -X ignore whitespace >actual 2>err &&
 	test_cmp expect actual &&
-	test_cmp err.expect err
+	test_must_be_empty err
 '
 
 test_expect_success 'info/exclude trumps core.excludesfile' '
diff --git a/t/t0030-stripspace.sh b/t/t0030-stripspace.sh
index bbf3e39e3d..b77948c618 100755
--- a/t/t0030-stripspace.sh
+++ b/t/t0030-stripspace.sh
@@ -110,31 +110,30 @@ test_expect_success \
 
 test_expect_success \
     'only consecutive blank lines should be completely removed' '
-    > expect &&
 
     printf "\n" | git stripspace >actual &&
-    test_cmp expect actual &&
+    test_must_be_empty actual &&
 
     printf "\n\n\n" | git stripspace >actual &&
-    test_cmp expect actual &&
+    test_must_be_empty actual &&
 
     printf "$sss\n$sss\n$sss\n" | git stripspace >actual &&
-    test_cmp expect actual &&
+    test_must_be_empty actual &&
 
     printf "$sss$sss\n$sss\n\n" | git stripspace >actual &&
-    test_cmp expect actual &&
+    test_must_be_empty actual &&
 
     printf "\n$sss\n$sss$sss\n" | git stripspace >actual &&
-    test_cmp expect actual &&
+    test_must_be_empty actual &&
 
     printf "$sss$sss$sss$sss\n\n\n" | git stripspace >actual &&
-    test_cmp expect actual &&
+    test_must_be_empty actual &&
 
     printf "\n$sss$sss$sss$sss\n\n" | git stripspace >actual &&
-    test_cmp expect actual &&
+    test_must_be_empty actual &&
 
     printf "\n\n$sss$sss$sss$sss\n" | git stripspace >actual &&
-    test_cmp expect actual
+    test_must_be_empty actual
 '
 
 test_expect_success \
diff --git a/t/t0300-credentials.sh b/t/t0300-credentials.sh
index 03bd31e9f2..82eaaea0f4 100755
--- a/t/t0300-credentials.sh
+++ b/t/t0300-credentials.sh
@@ -294,8 +294,7 @@ test_expect_success 'helpers can abort the process' '
 		-c credential.helper="!f() { echo quit=1; }; f" \
 		-c credential.helper="verbatim foo bar" \
 		credential fill >stdout &&
-	>expect &&
-	test_cmp expect stdout
+	test_must_be_empty stdout
 '
 
 test_expect_success 'empty helper spec resets helper list' '
diff --git a/t/t1011-read-tree-sparse-checkout.sh b/t/t1011-read-tree-sparse-checkout.sh
index 0c6f48f302..ba71b159ba 100755
--- a/t/t1011-read-tree-sparse-checkout.sh
+++ b/t/t1011-read-tree-sparse-checkout.sh
@@ -227,12 +227,11 @@ test_expect_success 'index removal and worktree narrowing at the same time' '
 '
 
 test_expect_success 'read-tree --reset removes outside worktree' '
-	>empty &&
 	echo init.t >.git/info/sparse-checkout &&
 	git checkout -f top &&
 	git reset --hard removed &&
 	git ls-files sub/added >result &&
-	test_cmp empty result
+	test_must_be_empty result
 '
 
 test_expect_success 'print errors when failed to update worktree' '
diff --git a/t/t1306-xdg-files.sh b/t/t1306-xdg-files.sh
index 8b14ab187c..21e139a313 100755
--- a/t/t1306-xdg-files.sh
+++ b/t/t1306-xdg-files.sh
@@ -114,11 +114,10 @@ test_expect_success 'Exclusion in a non-XDG global ignore file' '
 '
 
 test_expect_success 'Checking XDG ignore file when HOME is unset' '
-	>expected &&
 	(sane_unset HOME &&
 	 git config --unset core.excludesfile &&
 	 git ls-files --exclude-standard --ignored >actual) &&
-	test_cmp expected actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'Checking attributes in the XDG attributes file' '
@@ -132,10 +131,9 @@ test_expect_success 'Checking attributes in the XDG attributes file' '
 '
 
 test_expect_success 'Checking XDG attributes when HOME is unset' '
-	>expected &&
 	(sane_unset HOME &&
 	 git check-attr -a f >actual) &&
-	test_cmp expected actual
+	test_must_be_empty actual
 '
 
 test_expect_success '$XDG_CONFIG_HOME overrides $HOME/.config/git/attributes' '
diff --git a/t/t1403-show-ref.sh b/t/t1403-show-ref.sh
index 30354fd26c..5d955c3bff 100755
--- a/t/t1403-show-ref.sh
+++ b/t/t1403-show-ref.sh
@@ -26,26 +26,22 @@ test_expect_success 'show-ref' '
 	git show-ref refs/tags/A >actual &&
 	test_cmp expect actual &&
 
-	>expect &&
-
 	test_must_fail git show-ref D >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'show-ref -q' '
-	>expect &&
-
 	git show-ref -q A >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	git show-ref -q tags/A >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	git show-ref -q refs/tags/A >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	test_must_fail git show-ref -q D >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'show-ref --verify' '
@@ -54,32 +50,28 @@ test_expect_success 'show-ref --verify' '
 	git show-ref --verify refs/tags/A >actual &&
 	test_cmp expect actual &&
 
-	>expect &&
-
 	test_must_fail git show-ref --verify A >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	test_must_fail git show-ref --verify tags/A >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	test_must_fail git show-ref --verify D >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'show-ref --verify -q' '
-	>expect &&
-
 	git show-ref --verify -q refs/tags/A >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	test_must_fail git show-ref --verify -q A >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	test_must_fail git show-ref --verify -q tags/A >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	test_must_fail git show-ref --verify -q D >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'show-ref -d' '
@@ -113,19 +105,17 @@ test_expect_success 'show-ref -d' '
 	git show-ref -d --verify refs/heads/master >actual &&
 	test_cmp expect actual &&
 
-	>expect &&
-
 	test_must_fail git show-ref -d --verify master >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	test_must_fail git show-ref -d --verify heads/master >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	test_must_fail git show-ref --verify -d A C >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	test_must_fail git show-ref --verify -d tags/A tags/C >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 
 '
 
@@ -178,10 +168,8 @@ test_expect_success 'show-ref --verify HEAD' '
 	git show-ref --verify HEAD >actual &&
 	test_cmp expect actual &&
 
-	>expect &&
-
 	git show-ref --verify -q HEAD >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'show-ref --verify with dangling ref' '
diff --git a/t/t1507-rev-parse-upstream.sh b/t/t1507-rev-parse-upstream.sh
index 349f6e10af..fa3e499641 100755
--- a/t/t1507-rev-parse-upstream.sh
+++ b/t/t1507-rev-parse-upstream.sh
@@ -138,8 +138,7 @@ test_expect_success 'branch -d other@{u}' '
 	git checkout -t -b other master &&
 	git branch -d @{u} &&
 	git for-each-ref refs/heads/master >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'checkout other@{u}' '
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index 26dc3f1fc0..f79dfbbdd6 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -24,9 +24,8 @@ test_branch_upstream () {
 }
 
 status_uno_is_clean () {
-	>status.expect &&
 	git status -uno --porcelain >status.actual &&
-	test_cmp status.expect status.actual
+	test_must_be_empty status.actual
 }
 
 test_expect_success 'setup' '
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index be6e093142..166942c1bd 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -412,9 +412,8 @@ test_expect_success '"add" <path> <branch> dwims with checkout.defaultRemote' '
 		git fetch repo_upstream2 &&
 		test_must_fail git worktree add ../foo foo &&
 		git -c checkout.defaultRemote=repo_upstream worktree add ../foo foo &&
-		>status.expect &&
 		git status -uno --porcelain >status.actual &&
-		test_cmp status.expect status.actual
+		test_must_be_empty status.actual
 	) &&
 	(
 		cd foo &&
diff --git a/t/t2202-add-addremove.sh b/t/t2202-add-addremove.sh
index 17744e8c57..9ee659098c 100755
--- a/t/t2202-add-addremove.sh
+++ b/t/t2202-add-addremove.sh
@@ -48,8 +48,7 @@ test_expect_success 'Just "git add" is a no-op' '
 	>will-not-be-added &&
 	git add &&
 	git diff-index --name-status --cached HEAD >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_done
diff --git a/t/t3001-ls-files-others-exclude.sh b/t/t3001-ls-files-others-exclude.sh
index 3fc484e8c3..3b47647ed5 100755
--- a/t/t3001-ls-files-others-exclude.sh
+++ b/t/t3001-ls-files-others-exclude.sh
@@ -210,8 +210,7 @@ test_expect_success 'subdirectory ignore (toplevel)' '
 		cd top &&
 		git ls-files -o --exclude-standard
 	) >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'subdirectory ignore (l1/l2)' '
@@ -219,8 +218,7 @@ test_expect_success 'subdirectory ignore (l1/l2)' '
 		cd top/l1/l2 &&
 		git ls-files -o --exclude-standard
 	) >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'subdirectory ignore (l1)' '
@@ -228,8 +226,7 @@ test_expect_success 'subdirectory ignore (l1)' '
 		cd top/l1 &&
 		git ls-files -o --exclude-standard
 	) >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'show/hide empty ignored directory (setup)' '
@@ -251,8 +248,7 @@ test_expect_success 'hide empty ignored directory with --no-empty-directory' '
 		cd top &&
 		git ls-files -o -i --exclude l1 --directory --no-empty-directory
 	) >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'show/hide empty ignored sub-directory (setup)' '
@@ -277,8 +273,7 @@ test_expect_success 'hide empty ignored sub-directory with --no-empty-directory'
 		cd top &&
 		git ls-files -o -i --exclude l1 --directory --no-empty-directory
 	) >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'pattern matches prefix completely' '
diff --git a/t/t3070-wildmatch.sh b/t/t3070-wildmatch.sh
index dce102130f..46aca0af10 100755
--- a/t/t3070-wildmatch.sh
+++ b/t/t3070-wildmatch.sh
@@ -101,8 +101,7 @@ match_with_ls_files() {
 
 	match_stdout_stderr_cmp="
 		tr -d '\0' <actual.raw >actual &&
-		>expect.err &&
-		test_cmp expect.err actual.err &&
+		test_must_be_empty actual.err &&
 		test_cmp expect actual"
 
 	if test "$match_expect" = 'E'
diff --git a/t/t3201-branch-contains.sh b/t/t3201-branch-contains.sh
index 0ef1b6fdcc..0ea4fc4694 100755
--- a/t/t3201-branch-contains.sh
+++ b/t/t3201-branch-contains.sh
@@ -48,16 +48,14 @@ test_expect_success 'branch --contains master' '
 test_expect_success 'branch --no-contains=master' '
 
 	git branch --no-contains=master >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 
 '
 
 test_expect_success 'branch --no-contains master' '
 
 	git branch --no-contains master >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 
 '
 
@@ -94,8 +92,7 @@ test_expect_success 'branch --contains with pattern implies --list' '
 test_expect_success 'branch --no-contains with pattern implies --list' '
 
 	git branch --no-contains=master master >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 
 '
 
@@ -123,8 +120,7 @@ test_expect_success 'branch --merged with pattern implies --list' '
 test_expect_success 'side: branch --no-merged' '
 
 	git branch --no-merged >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 
 '
 
@@ -152,8 +148,7 @@ test_expect_success 'master: branch --no-merged' '
 test_expect_success 'branch --no-merged with pattern implies --list' '
 
 	git branch --no-merged=master master >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 
 '
 
diff --git a/t/t3700-add.sh b/t/t3700-add.sh
index 618750167a..37729ba258 100755
--- a/t/t3700-add.sh
+++ b/t/t3700-add.sh
@@ -188,9 +188,8 @@ test_expect_success 'git add --refresh with pathspec' '
 	git add foo bar baz && H=$(git rev-parse :foo) && git rm -f foo &&
 	echo "100644 $H 3	foo" | git update-index --index-info &&
 	test-tool chmtime -60 bar baz &&
-	>expect &&
 	git add --refresh bar >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	git diff-files --name-only >actual &&
 	! grep bar actual&&
diff --git a/t/t3910-mac-os-precompose.sh b/t/t3910-mac-os-precompose.sh
index 26dd5b7f78..54ce19e353 100755
--- a/t/t3910-mac-os-precompose.sh
+++ b/t/t3910-mac-os-precompose.sh
@@ -187,9 +187,8 @@ test_expect_failure 'handle existing decomposed filenames' '
 	echo content >"verbatim.$Adiarnfd" &&
 	git -c core.precomposeunicode=false add "verbatim.$Adiarnfd" &&
 	git commit -m "existing decomposed file" &&
-	>expect &&
 	git ls-files --exclude-standard -o "verbatim*" >untracked &&
-	test_cmp expect untracked
+	test_must_be_empty untracked
 '
 
 # Test if the global core.precomposeunicode stops autosensing
diff --git a/t/t4010-diff-pathspec.sh b/t/t4010-diff-pathspec.sh
index b7f25071cf..281f8fad0c 100755
--- a/t/t4010-diff-pathspec.sh
+++ b/t/t4010-diff-pathspec.sh
@@ -74,8 +74,7 @@ test_expect_success 'diff-tree pathspec' '
 	tree2=$(git write-tree) &&
 	echo "$tree2" &&
 	git diff-tree -r --name-only $tree $tree2 -- pa path1/a >current &&
-	>expected &&
-	test_cmp expected current
+	test_must_be_empty current
 '
 
 test_expect_success 'diff-tree with wildcard shows dir also matches' '
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index 41facf7abf..62ed0232d7 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -93,21 +93,20 @@ test_expect_success 'another test, without options' '
 	git diff >out &&
 	test_cmp expect out &&
 
-	>expect &&
 	git diff -w >out &&
-	test_cmp expect out &&
+	test_must_be_empty out &&
 
 	git diff -w -b >out &&
-	test_cmp expect out &&
+	test_must_be_empty out &&
 
 	git diff -w --ignore-space-at-eol >out &&
-	test_cmp expect out &&
+	test_must_be_empty out &&
 
 	git diff -w -b --ignore-space-at-eol >out &&
-	test_cmp expect out &&
+	test_must_be_empty out &&
 
 	git diff -w --ignore-cr-at-eol >out &&
-	test_cmp expect out &&
+	test_must_be_empty out &&
 
 	tr "Q_" "\015 " <<-\EOF >expect &&
 	diff --git a/x b/x
@@ -182,8 +181,7 @@ test_expect_success 'ignore-blank-lines: only new lines' '
 	test_seq 5 | sed "/3/i\\
 " >x &&
 	git diff --ignore-blank-lines >out &&
-	>expect &&
-	test_cmp expect out
+	test_must_be_empty out
 '
 
 test_expect_success 'ignore-blank-lines: only new lines with space' '
@@ -192,8 +190,7 @@ test_expect_success 'ignore-blank-lines: only new lines with space' '
 	test_seq 5 | sed "/3/i\\
  " >x &&
 	git diff -w --ignore-blank-lines >out &&
-	>expect &&
-	test_cmp expect out
+	test_must_be_empty out
 '
 
 test_expect_success 'ignore-blank-lines: after change' '
diff --git a/t/t4039-diff-assume-unchanged.sh b/t/t4039-diff-assume-unchanged.sh
index 23c0e357a7..53ac44b0f0 100755
--- a/t/t4039-diff-assume-unchanged.sh
+++ b/t/t4039-diff-assume-unchanged.sh
@@ -34,9 +34,8 @@ test_expect_success POSIXPERM 'find-copies-harder is not confused by mode bits'
 	git add exec &&
 	git commit -m exec &&
 	git update-index --assume-unchanged exec &&
-	>expect &&
 	git diff-files --find-copies-harder -- exec >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_done
diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh
index 8417e5a4b1..65da74c766 100755
--- a/t/t4200-rerere.sh
+++ b/t/t4200-rerere.sh
@@ -267,8 +267,7 @@ rerere_gc_custom_expiry_test () {
 		git -c "gc.rerereresolved=$right_now" \
 		    -c "gc.rerereunresolved=$right_now" rerere gc &&
 		find .git/rr-cache -type f | sort >actual &&
-		>expect &&
-		test_cmp expect actual
+		test_must_be_empty actual
 	'
 }
 
@@ -536,9 +535,8 @@ test_expect_success 'multiple identical conflicts' '
 
 	# We resolved file1 and file2
 	git rerere &&
-	>expect &&
 	git rerere remaining >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	# We must have recorded both of them
 	count_pre_post 2 2 &&
@@ -548,9 +546,8 @@ test_expect_success 'multiple identical conflicts' '
 	test_must_fail git merge six.1 &&
 	git rerere &&
 
-	>expect &&
 	git rerere remaining >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	concat_insert short 6.1 6.2 >file1.expect &&
 	concat_insert long 6.1 6.2 >file2.expect &&
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 25b1f8cc73..0b1cd3408b 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -340,10 +340,9 @@ test_expect_success PCRE 'log -F -E --perl-regexp --grep=<pcre> uses PCRE' '
 '
 
 test_expect_success 'log with grep.patternType configuration' '
-	>expect &&
 	git -c grep.patterntype=fixed \
 	log -1 --pretty=tformat:%s --grep=s.c.nd >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'log with grep.patternType configuration and command line' '
@@ -1625,9 +1624,8 @@ test_expect_success 'log diagnoses bogus HEAD' '
 '
 
 test_expect_success 'log does not default to HEAD when rev input is given' '
-	>expect &&
 	git log --branches=does-not-exist >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'set up --source tests' '
diff --git a/t/t4210-log-i18n.sh b/t/t4210-log-i18n.sh
index e585fe6129..7c519436ef 100755
--- a/t/t4210-log-i18n.sh
+++ b/t/t4210-log-i18n.sh
@@ -44,15 +44,13 @@ test_expect_success !MINGW 'log --grep searches in log output encoding (latin1)'
 '
 
 test_expect_success !MINGW 'log --grep does not find non-reencoded values (utf8)' '
-	>expect &&
 	git log --encoding=utf8 --format=%s --grep=$latin1_e >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'log --grep does not find non-reencoded values (latin1)' '
-	>expect &&
 	git log --encoding=ISO-8859-1 --format=%s --grep=$utf8_e >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_done
diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh
index 2d22a17c4a..6ee4d3f2d9 100755
--- a/t/t5310-pack-bitmaps.sh
+++ b/t/t5310-pack-bitmaps.sh
@@ -309,9 +309,8 @@ test_expect_success 'pack reuse respects --honor-pack-keep' '
 	done &&
 	reusable_pack --honor-pack-keep >empty.pack &&
 	git index-pack empty.pack &&
-	>expect &&
 	git show-index <empty.idx >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'pack reuse respects --local' '
@@ -319,17 +318,15 @@ test_expect_success 'pack reuse respects --local' '
 	test_when_finished "mv alt.git/objects/pack/* .git/objects/pack/" &&
 	reusable_pack --local >empty.pack &&
 	git index-pack empty.pack &&
-	>expect &&
 	git show-index <empty.idx >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'pack reuse respects --incremental' '
 	reusable_pack --incremental >empty.pack &&
 	git index-pack empty.pack &&
-	>expect &&
 	git show-index <empty.idx >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'truncated bitmap fails gracefully' '
diff --git a/t/t5313-pack-bounds-checks.sh b/t/t5313-pack-bounds-checks.sh
index 4fe4ad9d61..f1708d415e 100755
--- a/t/t5313-pack-bounds-checks.sh
+++ b/t/t5313-pack-bounds-checks.sh
@@ -90,9 +90,8 @@ test_expect_success 'matched bogus object count' '
 
 	# Unlike above, we should notice early that the .idx is totally
 	# bogus, and not even enumerate its contents.
-	>expect &&
 	git cat-file --batch-all-objects --batch-check >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	# But as before, we can do the same object-access checks.
 	test_must_fail git cat-file blob $object &&
diff --git a/t/t5505-remote.sh b/t/t5505-remote.sh
index 11e14a1e0f..6edec8fed7 100755
--- a/t/t5505-remote.sh
+++ b/t/t5505-remote.sh
@@ -74,8 +74,7 @@ test_expect_success 'add another remote' '
 		git for-each-ref "--format=%(refname)" refs/remotes |
 		sed -e "/^refs\/remotes\/origin\//d" \
 		    -e "/^refs\/remotes\/second\//d" >actual &&
-		>expect &&
-		test_cmp expect actual
+		test_must_be_empty actual
 	)
 '
 
@@ -112,8 +111,7 @@ test_expect_success C_LOCALE_OUTPUT 'remove remote' '
 		check_remote_track origin master side &&
 		git for-each-ref "--format=%(refname)" refs/remotes |
 		sed -e "/^refs\/remotes\/origin\//d" >actual &&
-		>expect &&
-		test_cmp expect actual
+		test_must_be_empty actual
 	)
 '
 
diff --git a/t/t5512-ls-remote.sh b/t/t5512-ls-remote.sh
index ea020040e8..bc5703ff9b 100755
--- a/t/t5512-ls-remote.sh
+++ b/t/t5512-ls-remote.sh
@@ -155,14 +155,12 @@ test_expect_success 'die with non-2 for wrong repository even with --exit-code'
 
 test_expect_success 'Report success even when nothing matches' '
 	git ls-remote other.git "refs/nsn/*" >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'Report no-match with --exit-code' '
 	test_expect_code 2 git ls-remote --exit-code other.git "refs/nsn/*" >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'Report match with --exit-code' '
diff --git a/t/t5514-fetch-multiple.sh b/t/t5514-fetch-multiple.sh
index 4b4b6673b8..0030c92e1a 100755
--- a/t/t5514-fetch-multiple.sh
+++ b/t/t5514-fetch-multiple.sh
@@ -152,7 +152,6 @@ test_expect_success 'git fetch --multiple (ignoring skipFetchAll)' '
 '
 
 test_expect_success 'git fetch --all --no-tags' '
-	>expect &&
 	git clone one test5 &&
 	git clone test5 test6 &&
 	(cd test5 && git tag test-tag) &&
@@ -161,7 +160,7 @@ test_expect_success 'git fetch --all --no-tags' '
 		git fetch --all --no-tags &&
 		git tag >output
 	) &&
-	test_cmp expect test6/output
+	test_must_be_empty test6/output
 '
 
 test_expect_success 'git fetch --all --tags' '
diff --git a/t/t5533-push-cas.sh b/t/t5533-push-cas.sh
index d38ecee217..0b0eb1d025 100755
--- a/t/t5533-push-cas.sh
+++ b/t/t5533-push-cas.sh
@@ -142,9 +142,8 @@ test_expect_success 'push to delete (protected, forced)' '
 		cd dst &&
 		git push --force --force-with-lease=master:master^ origin :master
 	) &&
-	>expect &&
 	git ls-remote src refs/heads/master >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'push to delete (allowed)' '
@@ -154,9 +153,8 @@ test_expect_success 'push to delete (allowed)' '
 		git push --force-with-lease=master origin :master 2>err &&
 		grep deleted err
 	) &&
-	>expect &&
 	git ls-remote src refs/heads/master >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'cover everything with default force-with-lease (protected)' '
diff --git a/t/t5612-clone-refspec.sh b/t/t5612-clone-refspec.sh
index fac5a73851..5582b3d5fd 100755
--- a/t/t5612-clone-refspec.sh
+++ b/t/t5612-clone-refspec.sh
@@ -97,8 +97,7 @@ test_expect_success 'clone with --no-tags' '
 		git fetch &&
 		git for-each-ref refs/tags >../actual
 	) &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success '--single-branch while HEAD pointing at master' '
@@ -140,8 +139,7 @@ test_expect_success '--single-branch while HEAD pointing at master and --no-tags
 		git fetch &&
 		git for-each-ref refs/tags >../actual
 	) &&
-	>expect &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 	test_line_count = 0 actual &&
 	# get tags with --tags overrides tagOpt
 	(
@@ -230,8 +228,7 @@ test_expect_success '--single-branch with detached' '
 		    -e "s|/remotes/origin/|/heads/|" >../actual
 	) &&
 	# nothing
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_done
diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index 969e4e9e52..fb4d295aa0 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -58,8 +58,7 @@ test_expect_success 'rev-list A..B and rev-list ^A B are the same' '
 
 test_expect_success 'propagate uninteresting flag down correctly' '
 	git rev-list --objects ^HEAD^{tree} HEAD^{tree} >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'symleft flag bit is propagated down from tag' '
diff --git a/t/t6009-rev-list-parent.sh b/t/t6009-rev-list-parent.sh
index 20e3e2554a..916d9692bc 100755
--- a/t/t6009-rev-list-parent.sh
+++ b/t/t6009-rev-list-parent.sh
@@ -31,8 +31,7 @@ test_expect_success setup '
 test_expect_success 'one is ancestor of others and should not be shown' '
 
 	git rev-list one --not four >result &&
-	>expect &&
-	test_cmp expect result
+	test_must_be_empty result
 
 '
 
@@ -144,8 +143,7 @@ test_expect_success 'ancestors with the same commit time' '
 		test_commit t$i
 	done &&
 	git rev-list t1^! --not t$i >result &&
-	>expect &&
-	test_cmp expect result
+	test_must_be_empty result
 '
 
 test_done
diff --git a/t/t6018-rev-list-glob.sh b/t/t6018-rev-list-glob.sh
index d3453c583c..02936c2f24 100755
--- a/t/t6018-rev-list-glob.sh
+++ b/t/t6018-rev-list-glob.sh
@@ -256,31 +256,27 @@ test_expect_success 'rev-list accumulates multiple --exclude' '
 '
 
 test_expect_failure 'rev-list should succeed with empty output on empty stdin' '
-	>expect &&
 	git rev-list --stdin <expect >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'rev-list should succeed with empty output with all refs excluded' '
-	>expect &&
 	git rev-list --exclude=* --all >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'rev-list should succeed with empty output with empty --all' '
 	(
 		test_create_repo empty &&
 		cd empty &&
-		>expect &&
 		git rev-list --all >actual &&
-		test_cmp expect actual
+		test_must_be_empty actual
 	)
 '
 
 test_expect_success 'rev-list should succeed with empty output with empty glob' '
-	>expect &&
 	git rev-list --glob=does-not-match-anything >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'shortlog accepts --glob/--tags/--remotes' '
diff --git a/t/t6019-rev-list-ancestry-path.sh b/t/t6019-rev-list-ancestry-path.sh
index dabebaee0b..beadaf6cca 100755
--- a/t/t6019-rev-list-ancestry-path.sh
+++ b/t/t6019-rev-list-ancestry-path.sh
@@ -95,10 +95,9 @@ test_expect_success 'rev-list --ancestry-path F...I' '
 
 # G.t is dropped in an "-s ours" merge
 test_expect_success 'rev-list G..M -- G.t' '
-	>expect &&
 	git rev-list --format=%s G..M -- G.t |
 	sed -e "/^commit /d" >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'rev-list --ancestry-path G..M -- G.t' '
diff --git a/t/t6022-merge-rename.sh b/t/t6022-merge-rename.sh
index b760c223c6..53cc9b2ffb 100755
--- a/t/t6022-merge-rename.sh
+++ b/t/t6022-merge-rename.sh
@@ -893,8 +893,7 @@ test_expect_success 'do not follow renames for empty files' '
 	git mv empty1 empty2 &&
 	git commit -m rename &&
 	test_must_fail git merge empty-base &&
-	>expect &&
-	test_cmp expect empty2
+	test_must_be_empty empty2
 '
 
 test_done
diff --git a/t/t6060-merge-index.sh b/t/t6060-merge-index.sh
index debadbd299..ddf34f0115 100755
--- a/t/t6060-merge-index.sh
+++ b/t/t6060-merge-index.sh
@@ -44,8 +44,7 @@ test_expect_success 'read-tree does not resolve content merge' '
 test_expect_success 'git merge-index git-merge-one-file resolves' '
 	git merge-index git-merge-one-file -a &&
 	git diff-files --name-only --diff-filter=U >unmerged &&
-	>expect &&
-	test_cmp expect unmerged &&
+	test_must_be_empty unmerged &&
 	test_cmp expect-merged file &&
 	git cat-file blob :file >file-index &&
 	test_cmp expect-merged file-index
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index e0496da812..024f8c06f7 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -796,9 +796,8 @@ test_expect_success ':remotename and :remoteref' '
 '
 
 test_expect_success 'for-each-ref --ignore-case ignores case' '
-	>expect &&
 	git for-each-ref --format="%(refname)" refs/heads/MASTER >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	echo refs/heads/master >expect &&
 	git for-each-ref --format="%(refname)" --ignore-case \
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index d7b319e919..93a6694f0e 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -693,9 +693,8 @@ test_expect_success \
 '
 
 test_expect_success 'The -n 100 invocation means -n --list 100, not -n100' '
-	>expect &&
 	git tag -n 100 >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	git tag -m "A msg" 100 &&
 	echo "100             A msg" >expect &&
@@ -974,9 +973,8 @@ test_expect_success GPG 'verifying a proper tag with --format pass and format ac
 '
 
 test_expect_success GPG 'verifying a forged tag with --format should fail silently' '
-	>expect &&
 	test_must_fail git tag -v --format="tagname : %(tag)" "forged-tag" >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 # blank and empty messages for signed tags:
@@ -1382,9 +1380,8 @@ test_expect_success 'message in editor has initial comment: first line' '
 test_expect_success \
 	'message in editor has initial comment: remainder' '
 	# remove commented lines from the remainder -- should be empty
-	>rest.expect &&
 	sed -e 1d -e "/^#/d" <actual >rest.actual &&
-	test_cmp rest.expect rest.actual
+	test_must_be_empty rest.actual
 '
 
 get_tag_header reuse $commit commit $time >expect
@@ -1466,19 +1463,18 @@ test_expect_success 'checking that first commit is in all tags (relative)' "
 
 # All the --contains tests above, but with --no-contains
 test_expect_success 'checking that first commit is not listed in any tag with --no-contains  (hash)' "
-	>expected &&
 	git tag -l --no-contains $hash1 v* >actual &&
-	test_cmp expected actual
+	test_must_be_empty actual
 "
 
 test_expect_success 'checking that first commit is in all tags (tag)' "
 	git tag -l --no-contains v1.0 v* >actual &&
-	test_cmp expected actual
+	test_must_be_empty actual
 "
 
 test_expect_success 'checking that first commit is in all tags (relative)' "
 	git tag -l --no-contains HEAD~2 v* >actual &&
-	test_cmp expected actual
+	test_must_be_empty actual
 "
 
 cat > expected <<EOF
@@ -1606,9 +1602,8 @@ test_expect_success 'checking that --contains can be used in non-list mode' '
 '
 
 test_expect_success 'checking that initial commit is in all tags with --no-contains' "
-	>expected &&
 	git tag -l --no-contains $hash1 v* >actual &&
-	test_cmp expected actual
+	test_must_be_empty actual
 "
 
 # mixing modes and options:
@@ -1905,7 +1900,6 @@ test_expect_success 'version sort with very long prerelease suffix' '
 '
 
 test_expect_success ULIMIT_STACK_SIZE '--contains and --no-contains work in a deep repo' '
-	>expect &&
 	i=1 &&
 	while test $i -lt 8000
 	do
@@ -1920,7 +1914,7 @@ EOF"
 	git checkout master &&
 	git tag far-far-away HEAD^ &&
 	run_with_limited_stack git tag --contains HEAD >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 	run_with_limited_stack git tag --no-contains HEAD >actual &&
 	test_line_count "-gt" 10 actual
 '
diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 7541ba5edb..00e09a375c 100755
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -626,12 +626,11 @@ test_expect_success TTY 'sub-commands of externals use their own pager' '
 
 test_expect_success TTY 'external command pagers override sub-commands' '
 	sane_unset PAGER GIT_PAGER &&
-	>expect &&
 	>actual &&
 	test_config pager.external false &&
 	test_config pager.log "sed s/^/log:/ >actual" &&
 	test_terminal git --exec-path=. external log --format=%s -1 &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'command with underscores does not complain' '
diff --git a/t/t7030-verify-tag.sh b/t/t7030-verify-tag.sh
index 291a1e2b07..1f068714c5 100755
--- a/t/t7030-verify-tag.sh
+++ b/t/t7030-verify-tag.sh
@@ -134,9 +134,8 @@ test_expect_success GPG 'verifying tag with --format' '
 '
 
 test_expect_success GPG 'verifying a forged tag with --format should fail silently' '
-	>expect &&
 	test_must_fail git verify-tag --format="tagname : %(tag)" $(cat forged1.tag) >actual-forged &&
-	test_cmp expect actual-forged
+	test_must_be_empty actual-forged
 '
 
 test_done
diff --git a/t/t7063-status-untracked-cache.sh b/t/t7063-status-untracked-cache.sh
index c61e304e97..6d8256a424 100755
--- a/t/t7063-status-untracked-cache.sh
+++ b/t/t7063-status-untracked-cache.sh
@@ -26,9 +26,8 @@ avoid_racy() {
 }
 
 status_is_clean() {
-	>../status.expect &&
 	git status --porcelain >../status.actual &&
-	test_cmp ../status.expect ../status.actual
+	test_must_be_empty ../status.actual
 }
 
 test_lazy_prereq UNTRACKED_CACHE '
diff --git a/t/t7102-reset.sh b/t/t7102-reset.sh
index 95653a08ca..97be0d968d 100755
--- a/t/t7102-reset.sh
+++ b/t/t7102-reset.sh
@@ -549,8 +549,7 @@ test_expect_success 'reset -N keeps removed files as intent-to-add' '
 
 	tree=$(git write-tree) &&
 	git ls-tree $tree new-file >actual &&
-	>expect &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 
 	git diff --name-only >actual &&
 	echo new-file >expect &&
@@ -563,9 +562,8 @@ test_expect_success 'reset --mixed sets up work tree' '
 		cd mixed_worktree &&
 		test_commit dummy
 	) &&
-	: >expect &&
 	git --git-dir=mixed_worktree/.git --work-tree=mixed_worktree reset >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_done
diff --git a/t/t7106-reset-unborn-branch.sh b/t/t7106-reset-unborn-branch.sh
index 0f95f00477..ecb85c3b82 100755
--- a/t/t7106-reset-unborn-branch.sh
+++ b/t/t7106-reset-unborn-branch.sh
@@ -12,9 +12,8 @@ test_expect_success 'reset' '
 	git add a b &&
 	git reset &&
 
-	>expect &&
 	git ls-files >actual &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'reset HEAD' '
@@ -39,9 +38,8 @@ test_expect_success PERL 'reset -p' '
 	echo y >yes &&
 	git reset -p <yes >output &&
 
-	>expect &&
 	git ls-files >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 	test_i18ngrep "Unstage" output
 '
 
@@ -61,9 +59,8 @@ test_expect_success 'reset --hard' '
 	test_when_finished "echo a >a" &&
 	git reset --hard &&
 
-	>expect &&
 	git ls-files >actual &&
-	test_cmp expect actual &&
+	test_must_be_empty actual &&
 	test_path_is_missing a
 '
 
diff --git a/t/t7401-submodule-summary.sh b/t/t7401-submodule-summary.sh
index 4e4c455502..1cd12b38c5 100755
--- a/t/t7401-submodule-summary.sh
+++ b/t/t7401-submodule-summary.sh
@@ -64,8 +64,7 @@ test_expect_success 'added submodule (subdirectory only)' "
 		cd sub &&
 		git submodule summary . >../actual
 	) &&
-	>expected &&
-	test_cmp expected actual
+	test_must_be_empty actual
 "
 
 test_expect_success 'added submodule (subdirectory with explicit path)' "
diff --git a/t/t7502-commit.sh b/t/t7502-commit.sh
index d33a3cb331..ca4a740da0 100755
--- a/t/t7502-commit.sh
+++ b/t/t7502-commit.sh
@@ -393,7 +393,6 @@ EOF
 
 test_expect_success !AUTOIDENT 'do not fire editor when committer is bogus' '
 	>.git/result &&
-	>expect &&
 
 	echo >>negative &&
 	(
@@ -403,7 +402,7 @@ test_expect_success !AUTOIDENT 'do not fire editor when committer is bogus' '
 		export GIT_EDITOR &&
 		test_must_fail git commit -e -m sample -a
 	) &&
-	test_cmp expect .git/result
+	test_must_be_empty .git/result
 '
 
 test_expect_success 'do not fire editor if -m <msg> was given' '
diff --git a/t/t7610-mergetool.sh b/t/t7610-mergetool.sh
index 047156e9d5..b18503de81 100755
--- a/t/t7610-mergetool.sh
+++ b/t/t7610-mergetool.sh
@@ -620,8 +620,7 @@ test_expect_success 'file with no base' '
 	git checkout -b test$test_count branch1 &&
 	test_must_fail git merge master &&
 	git mergetool --no-prompt --tool mybase -- both &&
-	>expected &&
-	test_cmp expected both
+	test_must_be_empty both
 '
 
 test_expect_success 'custom commands override built-ins' '
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index dcaab1557b..d826e24b45 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -691,8 +691,7 @@ test_expect_success 'log grep (5)' '
 
 test_expect_success 'log grep (6)' '
 	git log --author=-0700  --pretty=tformat:%s >actual &&
-	>expect &&
-	test_cmp expect actual
+	test_must_be_empty actual
 '
 
 test_expect_success 'log grep (7)' '
diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index b8e919e25d..1ef1a19003 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -253,10 +253,9 @@ test_suppress_self () {
 
 	mv msgtxt1 msgtxt1-$3 &&
 	sed -e '/^$/q' msgtxt1-$3 >"msghdr1-$3" &&
-	>"expected-no-cc-$3" &&
 
 	(grep '^Cc:' msghdr1-$3 >"actual-no-cc-$3";
-	 test_cmp expected-no-cc-$3 actual-no-cc-$3)
+	 test_must_be_empty actual-no-cc-$3)
 }
 
 test_suppress_self_unquoted () {
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 9e7f96223d..f8f869e26a 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -2191,12 +2191,11 @@ test_expect_success 'R: --import-marks-if-exists' '
 
 test_expect_success 'R: feature import-marks-if-exists' '
 	rm -f io.marks &&
-	>expect &&
 
 	git fast-import --export-marks=io.marks <<-\EOF &&
 	feature import-marks-if-exists=not_io.marks
 	EOF
-	test_cmp expect io.marks &&
+	test_must_be_empty io.marks &&
 
 	blob=$(echo hi | git hash-object --stdin) &&
 
@@ -2227,13 +2226,11 @@ test_expect_success 'R: feature import-marks-if-exists' '
 	EOF
 	test_cmp expect io.marks &&
 
-	>expect &&
-
 	git fast-import --import-marks-if-exists=not_io.marks \
 			--export-marks=io.marks <<-\EOF &&
 	feature import-marks-if-exists=io.marks
 	EOF
-	test_cmp expect io.marks
+	test_must_be_empty io.marks
 '
 
 test_expect_success 'R: import to output marks works without any content' '

diff --git a/t/t6018-rev-list-glob.sh b/t/t6018-rev-list-glob.sh
index 02936c2f24..0bf10d0686 100755
--- a/t/t6018-rev-list-glob.sh
+++ b/t/t6018-rev-list-glob.sh
@@ -256,7 +256,7 @@ test_expect_success 'rev-list accumulates multiple --exclude' '
 '
 
 test_expect_failure 'rev-list should succeed with empty output on empty stdin' '
-	git rev-list --stdin <expect >actual &&
+	git rev-list --stdin </dev/null >actual &&
 	test_must_be_empty actual
 '
 

diff --git a/t/Makefile b/t/Makefile
index ea36cf7ac7..c7b1655593 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -54,10 +54,11 @@ pre-clean:
        $(RM) -r '$(TEST_RESULTS_DIRECTORY_SQ)'

 clean-except-prove-cache:
-       $(RM) -r 'trash directory'.* '$(TEST_RESULTS_DIRECTORY_SQ)'
+       $(RM) -r 'trash directory'.*
        $(RM) -r valgrind/bin

 clean: clean-except-prove-cache
+       $(RM) '$(TEST_RESULTS_DIRECTORY_SQ)'

 distclean: clean
        $(RM) .prove

And then scanned the results of a '--verbose-log -x' test run with:

  grep -E '^(awk|basename|cat|cd|chmod|cmp|cp|cut|diff|dirname|egrep|find|fgrep|grep|gunzip|gzip|ln|mkdir|mkfifo|mktemp|mv|readlink|rmdir|sed|sort|tar|touch|tr|ulimit|umask|uniq|unzip|wc|zipinfo|t[0-9][0-9][0-9][0-9]-[^:]*\.sh):
' test-results/*.out

and then, for lack of something better to do ;), I started looking at
the simpler looking errors.

I've though about how a check like this could be automated, but
haven't had any workable idea yet.  There are commands that can
legitimately print errors, e.g. when checking for a prereq which the
system doesn't have (e.g. the 'tar' errors above, I think).  And the
list of system commands in the grep pattern above is surely incomplete
and will likely change in the future...

revision.c, t/t6018-rev-list-glob.sh

diff --git a/revision.c b/revision.c
index d12e6d8a4a..21fb413511 100644
--- a/revision.c
+++ b/revision.c
@@ -2441,6 +2441,19 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 		object = get_reference(revs, revs->def, &oid, 0);
 		add_pending_object_with_mode(revs, object, revs->def, oc.mode);
 	}
+	/* 
+	 * Even if revs->pending is empty after all the above, if we
+	 * handled "--stdin", then the caller really meant to give us
+	 * an empty commit range.  Just let the traversal give an
+	 * empty result without causing a "no input?  do you know how
+	 * to use this command?" failure.
+	 *
+	 * NOTE!!!  Because "--stdin </dev/null --default HEAD" should
+	 * default to HEAD, this must come _after_ the above block
+	 * that deals with revs->ref fallback.
+	 */
+	if (read_from_stdin)
+		revs->rev_input_given = 1;
 
 	/* Did the user ask for any diff output? Run the diff! */
 	if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
diff --git a/t/t6018-rev-list-glob.sh b/t/t6018-rev-list-glob.sh
index 02936c2f24..db8a7834d8 100755
--- a/t/t6018-rev-list-glob.sh
+++ b/t/t6018-rev-list-glob.sh
@@ -255,8 +255,8 @@ test_expect_success 'rev-list accumulates multiple --exclude' '
 	compare rev-list "--exclude=refs/remotes/* --exclude=refs/tags/* --all" --branches
 '
 
-test_expect_failure 'rev-list should succeed with empty output on empty stdin' '
+test_expect_success 'rev-list should succeed with empty output on empty stdin' '
 	git rev-list --stdin </dev/null >actual &&
 	test_must_be_empty actual
 '
 

builtin/rev-list.c, revision.c, revision.h, t/t6018-rev-list-glob.sh

diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 5b07f3f4a2..ed0ea7dc5b 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -493,7 +493,7 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 	if ((!revs.commits && reflog_walk_empty(revs.reflog_info) &&
 	     (!(revs.tag_objects || revs.tree_objects || revs.blob_objects) &&
 	      !revs.pending.nr) &&
-	     !revs.rev_input_given) ||
+	     !revs.rev_input_given && !revs.read_from_stdin) ||
 	    revs.diff)
 		usage(rev_list_usage);
 
diff --git a/revision.c b/revision.c
index de4dce600d..4d53102cf4 100644
--- a/revision.c
+++ b/revision.c
@@ -2369,6 +2369,7 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 				}
 				if (read_from_stdin++)
 					die("--stdin given twice?");
+				revs->read_from_stdin = 1;
 				read_revisions_from_stdin(revs, &prune_data);
 				continue;
 			}
diff --git a/revision.h b/revision.h
index 007278cc11..1225957927 100644
--- a/revision.h
+++ b/revision.h
@@ -82,6 +82,11 @@ struct rev_info {
 	 */
 	int rev_input_given;
 
+	/*
+	 * Whether we read from stdin due to the --stdin option.
+	 */
+	int read_from_stdin;
+
 	/* topo-sort */
 	enum rev_sort_order sort_order;
 
diff --git a/t/t6018-rev-list-glob.sh b/t/t6018-rev-list-glob.sh
index 0bf10d0686..db8a7834d8 100755
--- a/t/t6018-rev-list-glob.sh
+++ b/t/t6018-rev-list-glob.sh
@@ -255,7 +255,7 @@ test_expect_success 'rev-list accumulates multiple --exclude' '
 	compare rev-list "--exclude=refs/remotes/* --exclude=refs/tags/* --all" --branches
 '
 
-test_expect_failure 'rev-list should succeed with empty output on empty stdin' '
+test_expect_success 'rev-list should succeed with empty output on empty stdin' '
 	git rev-list --stdin </dev/null >actual &&
 	test_must_be_empty actual
 '

builtin/rev-list.c, revision.c, revision.h, t/t6018-rev-list-glob.sh

diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 5b07f3f4a2..ed0ea7dc5b 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -493,7 +493,7 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 	if ((!revs.commits && reflog_walk_empty(revs.reflog_info) &&
 	     (!(revs.tag_objects || revs.tree_objects || revs.blob_objects) &&
 	      !revs.pending.nr) &&
-	     !revs.rev_input_given) ||
+	     !revs.rev_input_given && !revs.read_from_stdin) ||
 	    revs.diff)
 		usage(rev_list_usage);
 
diff --git a/revision.c b/revision.c
index de4dce600d..46228f82ee 100644
--- a/revision.c
+++ b/revision.c
@@ -2318,7 +2318,7 @@ static void NORETURN diagnose_missing_default(const char *def)
  */
 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
 {
-	int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0, revarg_opt;
+	int i, flags, left, seen_dashdash, got_rev_arg = 0, revarg_opt;
 	struct argv_array prune_data = ARGV_ARRAY_INIT;
 	const char *submodule = NULL;
 
@@ -2348,7 +2348,6 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 	revarg_opt = opt ? opt->revarg_opt : 0;
 	if (seen_dashdash)
 		revarg_opt |= REVARG_CANNOT_BE_FILENAME;
-	read_from_stdin = 0;
 	for (left = i = 1; i < argc; i++) {
 		const char *arg = argv[i];
 		if (*arg == '-') {
@@ -2367,7 +2366,7 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 					argv[left++] = arg;
 					continue;
 				}
-				if (read_from_stdin++)
+				if (revs->read_from_stdin++)
 					die("--stdin given twice?");
 				read_revisions_from_stdin(revs, &prune_data);
 				continue;
diff --git a/revision.h b/revision.h
index 007278cc11..1225957927 100644
--- a/revision.h
+++ b/revision.h
@@ -82,6 +82,11 @@ struct rev_info {
 	 */
 	int rev_input_given;
 
+	/*
+	 * Whether we read from stdin due to the --stdin option.
+	 */
+	int read_from_stdin;
+
 	/* topo-sort */
 	enum rev_sort_order sort_order;
 
diff --git a/t/t6018-rev-list-glob.sh b/t/t6018-rev-list-glob.sh
index 0bf10d0686..db8a7834d8 100755
--- a/t/t6018-rev-list-glob.sh
+++ b/t/t6018-rev-list-glob.sh
@@ -255,7 +255,7 @@ test_expect_success 'rev-list accumulates multiple --exclude' '
 	compare rev-list "--exclude=refs/remotes/* --exclude=refs/tags/* --all" --branches
 '
 
-test_expect_failure 'rev-list should succeed with empty output on empty stdin' '
+test_expect_success 'rev-list should succeed with empty output on empty stdin' '
 	git rev-list --stdin </dev/null >actual &&
 	test_must_be_empty actual
 '

diff --git a/checkout.c b/checkout.c
index bdefc888ba..80e430cda8 100644
--- a/checkout.c
+++ b/checkout.c
@@ -10,6 +10,8 @@ struct tracking_name_data {
 	int unique;
 };
 
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 1 }
+
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
 	struct tracking_name_data *cb = cb_data;
@@ -32,7 +34,7 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 
 const char *unique_tracking_name(const char *name, struct object_id *oid)
 {
-	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
+	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);

diff --git a/checkout.h b/checkout.h
index 9980711179..4cd4cd1c23 100644
--- a/checkout.h
+++ b/checkout.h
@@ -8,6 +8,7 @@
  * tracking branch.  Return the name of the remote if such a branch
  * exists, NULL otherwise.
  */
-extern const char *unique_tracking_name(const char *name, struct object_id *oid);
+extern const char *unique_tracking_name(const char *name,
+					struct object_id *oid);
 
 #endif /* CHECKOUT_H */

diff --git a/checkout.c b/checkout.c
index 80e430cda8..7662a39a62 100644
--- a/checkout.c
+++ b/checkout.c
@@ -7,10 +7,10 @@ struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
-	int unique;
+	int num_matches;
 };
 
-#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 1 }
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0 }
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
@@ -23,9 +23,9 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		free(query.dst);
 		return 0;
 	}
+	cb->num_matches++;
 	if (cb->dst_ref) {
 		free(query.dst);
-		cb->unique = 0;
 		return 0;
 	}
 	cb->dst_ref = query.dst;
@@ -39,7 +39,7 @@ const char *unique_tracking_name(const char *name, struct object_id *oid)
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	free(cb_data.src_ref);
-	if (cb_data.unique)
+	if (cb_data.num_matches == 1)
 		return cb_data.dst_ref;
 	free(cb_data.dst_ref);
 	return NULL;

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 72457fb7d5..8c93c55cbc 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1265,8 +1265,10 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	}
 
 	UNLEAK(opts);
-	if (opts.patch_mode || opts.pathspec.nr)
-		return checkout_paths(&opts, new_branch_info.name);
-	else
+	if (opts.patch_mode || opts.pathspec.nr) {
+		int ret = checkout_paths(&opts, new_branch_info.name);
+		return ret;
+	} else {
 		return checkout_branch(&opts, &new_branch_info);
+	}
 }

Documentation/config.txt, advice.c, advice.h, builtin/checkout.c, t/t2024-checkout-dwim.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index ab641bf5a9..dfc0413a84 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -344,6 +344,13 @@ advice.*::
 		Advice shown when you used linkgit:git-checkout[1] to
 		move to the detach HEAD state, to instruct how to create
 		a local branch after the fact.
+	checkoutAmbiguousRemoteBranchName::
+		Advice shown when the argument to
+		linkgit:git-checkout[1] ambiguously resolves to a
+		remote tracking branch on more than one remote in
+		situations where an unambiguous argument would have
+		otherwise caused a remote-tracking branch to be
+		checked out.
 	amWorkDir::
 		Advice that shows the location of the patch file when
 		linkgit:git-am[1] fails to apply it.
diff --git a/advice.c b/advice.c
index 370a56d054..75e7dede90 100644
--- a/advice.c
+++ b/advice.c
@@ -21,6 +21,7 @@ int advice_add_embedded_repo = 1;
 int advice_ignored_hook = 1;
 int advice_waiting_for_editor = 1;
 int advice_graft_file_deprecated = 1;
+int advice_checkout_ambiguous_remote_branch_name = 1;
 
 static int advice_use_color = -1;
 static char advice_colors[][COLOR_MAXLEN] = {
@@ -72,6 +73,7 @@ static struct {
 	{ "ignoredhook", &advice_ignored_hook },
 	{ "waitingforeditor", &advice_waiting_for_editor },
 	{ "graftfiledeprecated", &advice_graft_file_deprecated },
+	{ "checkoutambiguousremotebranchname", &advice_checkout_ambiguous_remote_branch_name },
 
 	/* make this an alias for backward compatibility */
 	{ "pushnonfastforward", &advice_push_update_rejected }
diff --git a/advice.h b/advice.h
index 9f5064e82a..4d11d51d43 100644
--- a/advice.h
+++ b/advice.h
@@ -22,6 +22,7 @@ extern int advice_add_embedded_repo;
 extern int advice_ignored_hook;
 extern int advice_waiting_for_editor;
 extern int advice_graft_file_deprecated;
+extern int advice_checkout_ambiguous_remote_branch_name;
 
 int git_default_advice_config(const char *var, const char *value);
 __attribute__((format (printf, 1, 2)))
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 8c93c55cbc..baa027455a 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -22,6 +22,7 @@
 #include "resolve-undo.h"
 #include "submodule-config.h"
 #include "submodule.h"
+#include "advice.h"
 
 static const char * const checkout_usage[] = {
 	N_("git checkout [<options>] <branch>"),
@@ -1267,6 +1268,18 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	UNLEAK(opts);
 	if (opts.patch_mode || opts.pathspec.nr) {
 		int ret = checkout_paths(&opts, new_branch_info.name);
+		if (ret && dwim_remotes_matched > 1 &&
+		    advice_checkout_ambiguous_remote_branch_name)
+			advise(_("'%s' matched more than one remote tracking branch.\n"
+				 "We found %d remotes with a reference that matched. So we fell back\n"
+				 "on trying to resolve the argument as a path, but failed there too!\n"
+				 "\n"
+				 "If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
+				 "you can do so by fully qualifying the name with the --track option:\n"
+				 "\n"
+				 "    git checkout --track origin/<name>"),
+			       argv[0],
+			       dwim_remotes_matched);
 		return ret;
 	} else {
 		return checkout_branch(&opts, &new_branch_info);
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index ed32828105..fef263a858 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -76,6 +76,20 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_branch master
 '
 
+test_expect_success 'checkout of branch from multiple remotes fails with advice' '
+	git checkout -B master &&
+	test_might_fail git branch -D foo &&
+	test_must_fail git checkout foo 2>stderr &&
+	test_branch master &&
+	status_uno_is_clean &&
+	test_i18ngrep "^hint: " stderr &&
+	test_must_fail git -c advice.checkoutAmbiguousRemoteBranchName=false \
+		checkout foo 2>stderr &&
+	test_branch master &&
+	status_uno_is_clean &&
+	test_i18ngrep ! "^hint: " stderr
+'
+
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
 	git checkout -B master &&
 	test_might_fail git branch -D bar &&

Documentation/config.txt, Documentation/git-checkout.txt, Documentation/git-worktree.txt, builtin/checkout.c, checkout.c, t/t2024-checkout-dwim.sh, t/t2025-worktree-add.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index dfc0413a84..aef2769211 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -350,7 +350,10 @@ advice.*::
 		remote tracking branch on more than one remote in
 		situations where an unambiguous argument would have
 		otherwise caused a remote-tracking branch to be
-		checked out.
+		checked out. See the `checkout.defaultRemote`
+		configuration variable for how to set a given remote
+		to used by default in some situations where this
+		advice would be printed.
 	amWorkDir::
 		Advice that shows the location of the patch file when
 		linkgit:git-am[1] fails to apply it.
@@ -1105,6 +1108,22 @@ browser.<tool>.path::
 	browse HTML help (see `-w` option in linkgit:git-help[1]) or a
 	working repository in gitweb (see linkgit:git-instaweb[1]).
 
+checkout.defaultRemote::
+	When you run 'git checkout <something>' and only have one
+	remote, it may implicitly fall back on checking out and
+	tracking e.g. 'origin/<something>'. This stops working as soon
+	as you have more than one remote with a '<something>'
+	reference. This setting allows for setting the name of a
+	preferred remote that should always win when it comes to
+	disambiguation. The typical use-case is to set this to
+	`origin`.
++
+Currently this is used by linkgit:git-checkout[1] when 'git checkout
+<something>' will checkout the '<something>' branch on another remote,
+and by linkgit:git-worktree[1] when 'git worktree add' refers to a
+remote branch. This setting might be used for other checkout-like
+commands or functionality in the future.
+
 clean.requireForce::
 	A boolean to make git-clean do nothing unless given -f,
 	-i or -n.   Defaults to true.
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index ca5fc9c798..9db02928c4 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -38,6 +38,15 @@ equivalent to
 $ git checkout -b <branch> --track <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes and one of them is named by
+the `checkout.defaultRemote` configuration variable, we'll use that
+one for the purposes of disambiguation, even if the `<branch>` isn't
+unique across all remotes. Set it to
+e.g. `checkout.defaultRemote=origin` to always checkout remote
+branches from there if `<branch>` is ambiguous but exists on the
+'origin' remote. See also `checkout.defaultRemote` in
+linkgit:git-config[1].
++
 You could omit <branch>, in which case the command degenerates to
 "check out the current branch", which is a glorified no-op with
 rather expensive side-effects to show only the tracking information,
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index afc6576a14..9c26be40f4 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -60,6 +60,15 @@ with a matching name, treat as equivalent to:
 $ git worktree add --track -b <branch> <path> <remote>/<branch>
 ------------
 +
+If the branch exists in multiple remotes and one of them is named by
+the `checkout.defaultRemote` configuration variable, we'll use that
+one for the purposes of disambiguation, even if the `<branch>` isn't
+unique across all remotes. Set it to
+e.g. `checkout.defaultRemote=origin` to always checkout remote
+branches from there if `<branch>` is ambiguous but exists on the
+'origin' remote. See also `checkout.defaultRemote` in
+linkgit:git-config[1].
++
 If `<commit-ish>` is omitted and neither `-b` nor `-B` nor `--detach` used,
 then, as a convenience, the new worktree is associated with a branch
 (call it `<branch>`) named after `$(basename <path>)`.  If `<branch>`
diff --git a/builtin/checkout.c b/builtin/checkout.c
index baa027455a..5b357e922a 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -912,8 +912,10 @@ static int parse_branchname_arg(int argc, const char **argv,
 	 *   (b) If <something> is _not_ a commit, either "--" is present
 	 *       or <something> is not a path, no -t or -b was given, and
 	 *       and there is a tracking branch whose name is <something>
-	 *       in one and only one remote, then this is a short-hand to
-	 *       fork local <something> from that remote-tracking branch.
+	 *       in one and only one remote (or if the branch exists on the
+	 *       remote named in checkout.defaultRemote), then this is a
+	 *       short-hand to fork local <something> from that
+	 *       remote-tracking branch.
 	 *
 	 *   (c) Otherwise, if "--" is present, treat it like case (1).
 	 *
@@ -1277,7 +1279,11 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 				 "If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
 				 "you can do so by fully qualifying the name with the --track option:\n"
 				 "\n"
-				 "    git checkout --track origin/<name>"),
+				 "    git checkout --track origin/<name>\n"
+				 "\n"
+				 "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
+				 "one remote, e.g. the 'origin' remote, consider setting\n"
+				 "checkout.defaultRemote=origin in your config."),
 			       argv[0],
 			       dwim_remotes_matched);
 		return ret;
diff --git a/checkout.c b/checkout.c
index ee3a7e9c05..c72e9f9773 100644
--- a/checkout.c
+++ b/checkout.c
@@ -2,15 +2,19 @@
 #include "remote.h"
 #include "refspec.h"
 #include "checkout.h"
+#include "config.h"
 
 struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
 	int num_matches;
+	const char *default_remote;
+	char *default_dst_ref;
+	struct object_id *default_dst_oid;
 };
 
-#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0 }
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0, NULL, NULL, NULL }
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
@@ -24,6 +28,12 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		return 0;
 	}
 	cb->num_matches++;
+	if (cb->default_remote && !strcmp(remote->name, cb->default_remote)) {
+		struct object_id *dst = xmalloc(sizeof(*cb->default_dst_oid));
+		cb->default_dst_ref = xstrdup(query.dst);
+		oidcpy(dst, cb->dst_oid);
+		cb->default_dst_oid = dst;
+	}
 	if (cb->dst_ref) {
 		free(query.dst);
 		return 0;
@@ -36,14 +46,26 @@ const char *unique_tracking_name(const char *name, struct object_id *oid,
 				 int *dwim_remotes_matched)
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
+	const char *default_remote = NULL;
+	if (!git_config_get_string_const("checkout.defaultremote", &default_remote))
+		cb_data.default_remote = default_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
 	if (dwim_remotes_matched)
 		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
-	if (cb_data.num_matches == 1)
+	free((char *)default_remote);
+	if (cb_data.num_matches == 1) {
+		free(cb_data.default_dst_ref);
+		free(cb_data.default_dst_oid);
 		return cb_data.dst_ref;
+	}
 	free(cb_data.dst_ref);
+	if (cb_data.default_dst_ref) {
+		oidcpy(oid, cb_data.default_dst_oid);
+		free(cb_data.default_dst_oid);
+		return cb_data.default_dst_ref;
+	}
 	return NULL;
 }
diff --git a/t/t2024-checkout-dwim.sh b/t/t2024-checkout-dwim.sh
index fef263a858..9f17ac92f1 100755
--- a/t/t2024-checkout-dwim.sh
+++ b/t/t2024-checkout-dwim.sh
@@ -87,7 +87,23 @@ test_expect_success 'checkout of branch from multiple remotes fails with advice'
 		checkout foo 2>stderr &&
 	test_branch master &&
 	status_uno_is_clean &&
-	test_i18ngrep ! "^hint: " stderr
+	test_i18ngrep ! "^hint: " stderr &&
+	# Make sure the likes of checkout -p do not print this hint
+	git checkout -p foo 2>stderr &&
+	test_i18ngrep ! "^hint: " stderr &&
+	status_uno_is_clean
+'
+
+test_expect_success 'checkout of branch from multiple remotes succeeds with checkout.defaultRemote #1' '
+	git checkout -B master &&
+	status_uno_is_clean &&
+	test_might_fail git branch -D foo &&
+
+	git -c checkout.defaultRemote=repo_a checkout foo &&
+	status_uno_is_clean &&
+	test_branch foo &&
+	test_cmp_rev remotes/repo_a/foo HEAD &&
+	test_branch_upstream foo repo_a foo
 '
 
 test_expect_success 'checkout of branch from a single remote succeeds #1' '
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index d2e49f7632..be6e093142 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -402,6 +402,27 @@ test_expect_success '"add" <path> <branch> dwims' '
 	)
 '
 
+test_expect_success '"add" <path> <branch> dwims with checkout.defaultRemote' '
+	test_when_finished rm -rf repo_upstream repo_dwim foo &&
+	setup_remote_repo repo_upstream repo_dwim &&
+	git init repo_dwim &&
+	(
+		cd repo_dwim &&
+		git remote add repo_upstream2 ../repo_upstream &&
+		git fetch repo_upstream2 &&
+		test_must_fail git worktree add ../foo foo &&
+		git -c checkout.defaultRemote=repo_upstream worktree add ../foo foo &&
+		>status.expect &&
+		git status -uno --porcelain >status.actual &&
+		test_cmp status.expect status.actual
+	) &&
+	(
+		cd foo &&
+		test_branch_upstream foo repo_upstream foo &&
+		test_cmp_rev refs/remotes/repo_upstream/foo refs/heads/foo
+	)
+'
+
 test_expect_success 'git worktree add does not match remote' '
 	test_when_finished rm -rf repo_a repo_b foo &&
 	setup_remote_repo repo_a repo_b &&

builtin/checkout.c, builtin/worktree.c, checkout.c, checkout.h

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 2e1d2376d2..72457fb7d5 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -878,7 +878,8 @@ static int parse_branchname_arg(int argc, const char **argv,
 				int dwim_new_local_branch_ok,
 				struct branch_info *new_branch_info,
 				struct checkout_opts *opts,
-				struct object_id *rev)
+				struct object_id *rev,
+				int *dwim_remotes_matched)
 {
 	struct tree **source_tree = &opts->source_tree;
 	const char **new_branch = &opts->new_branch;
@@ -972,7 +973,8 @@ static int parse_branchname_arg(int argc, const char **argv,
 			recover_with_dwim = 0;
 
 		if (recover_with_dwim) {
-			const char *remote = unique_tracking_name(arg, rev);
+			const char *remote = unique_tracking_name(arg, rev,
+								  dwim_remotes_matched);
 			if (remote) {
 				*new_branch = arg;
 				arg = remote;
@@ -1109,6 +1111,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	struct branch_info new_branch_info;
 	char *conflict_style = NULL;
 	int dwim_new_local_branch = 1;
+	int dwim_remotes_matched = 0;
 	struct option options[] = {
 		OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
 		OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
@@ -1219,7 +1222,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 			opts.track == BRANCH_TRACK_UNSPECIFIED &&
 			!opts.new_branch;
 		int n = parse_branchname_arg(argc, argv, dwim_ok,
-					     &new_branch_info, &opts, &rev);
+					     &new_branch_info, &opts, &rev,
+					     &dwim_remotes_matched);
 		argv += n;
 		argc -= n;
 	}
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 5c7d2bb180..a763dbdccb 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -412,7 +412,7 @@ static const char *dwim_branch(const char *path, const char **new_branch)
 	if (guess_remote) {
 		struct object_id oid;
 		const char *remote =
-			unique_tracking_name(*new_branch, &oid);
+			unique_tracking_name(*new_branch, &oid, NULL);
 		return remote;
 	}
 	return NULL;
@@ -484,7 +484,7 @@ static int add(int ac, const char **av, const char *prefix)
 
 		commit = lookup_commit_reference_by_name(branch);
 		if (!commit) {
-			remote = unique_tracking_name(branch, &oid);
+			remote = unique_tracking_name(branch, &oid, NULL);
 			if (remote) {
 				new_branch = branch;
 				branch = remote;
diff --git a/checkout.c b/checkout.c
index 7662a39a62..ee3a7e9c05 100644
--- a/checkout.c
+++ b/checkout.c
@@ -32,12 +32,15 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 	return 0;
 }
 
-const char *unique_tracking_name(const char *name, struct object_id *oid)
+const char *unique_tracking_name(const char *name, struct object_id *oid,
+				 int *dwim_remotes_matched)
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
+	if (dwim_remotes_matched)
+		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
 	if (cb_data.num_matches == 1)
 		return cb_data.dst_ref;
diff --git a/checkout.h b/checkout.h
index 4cd4cd1c23..6b2073310c 100644
--- a/checkout.h
+++ b/checkout.h
@@ -9,6 +9,7 @@
  * exists, NULL otherwise.
  */
 extern const char *unique_tracking_name(const char *name,
-					struct object_id *oid);
+					struct object_id *oid,
+					int *dwim_remotes_matched);
 
 #endif /* CHECKOUT_H */