[PATCH 1/2] branch: suggest <remote>/<branch> on upstream slip

From

Harald Nordgren via GitGitGadget <gitgitgadget@gmail.com>

Date

Jun 12, 2026, 11:10 UTC

Message-ID

<21684539debaf433b6b63404e1a7622a5cc33283.1781262619.git.gitgitgadget@gmail.com>

In-Reply-To

<pull.2331.git.git.1781262619.gitgitgadget@gmail.com>

From: Harald Nordgren <haraldnordgren@gmail.com>

Signed-off-by: Harald Nordgren <haraldnordgren@gmail.com>
---
 builtin/branch.c  | 17 +++++++++++++++++
 t/t3200-branch.sh | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/builtin/branch.c b/builtin/branch.c
index 1572a4f9ef..7ad3efb908 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -957,6 +957,23 @@ int cmd_branch(int argc,
 		if (!refs_ref_exists(get_main_ref_store(the_repository), branch->refname)) {
 			if (!argc || branch_checked_out(branch->refname))
 				die(_("no commit on branch '%s' yet"), branch->name);
+			if (argc == 1 && !strchr(new_upstream, '/') &&
+			    remote_is_configured(remote_get(new_upstream), 0)) {
+				struct strbuf remote_ref = STRBUF_INIT;
+
+				strbuf_addf(&remote_ref, "refs/remotes/%s/%s",
+					    new_upstream, argv[0]);
+				if (refs_ref_exists(get_main_ref_store(the_repository),
+						    remote_ref.buf)) {
+					int code = die_message(_("--set-upstream-to takes a single <remote>/<branch> argument"));
+					advise_if_enabled(ADVICE_SET_UPSTREAM_FAILURE,
+							  _("Did you mean to use: git branch --set-upstream-to=%s/%s?"),
+							  new_upstream, argv[0]);
+					strbuf_release(&remote_ref);
+					exit(code);
+				}
+				strbuf_release(&remote_ref);
+			}
 			die(_("branch '%s' does not exist"), branch->name);
 		}
 
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index e7829c2c4b..e2682a83a0 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -1022,6 +1022,44 @@ test_expect_success '--set-upstream-to fails on a missing dst branch' '
 	test_cmp expect err
 '
 
+test_expect_success '--set-upstream-to suggests <remote>/<branch> on slip' '
+	test_when_finished "git remote remove slip-remote" &&
+	git remote add slip-remote . &&
+	git update-ref refs/remotes/slip-remote/slip-feature HEAD &&
+	test_must_fail git branch --set-upstream-to slip-remote slip-feature 2>err &&
+	test_grep "takes a single <remote>/<branch> argument" err &&
+	test_grep "hint: Did you mean to use: git branch --set-upstream-to=slip-remote/slip-feature?" err &&
+	test_must_fail git -c advice.setUpstreamFailure=false \
+		branch --set-upstream-to slip-remote slip-feature 2>err &&
+	test_grep ! "Did you mean" err
+'
+
+test_expect_success '--set-upstream-to does not suggest when no matching remote ref' '
+	test_when_finished "git remote remove slip-remote" &&
+	git remote add slip-remote . &&
+	test_must_fail git branch --set-upstream-to slip-remote no-such-branch 2>err &&
+	test_grep "branch ${SQ}no-such-branch${SQ} does not exist" err &&
+	test_grep ! "Did you mean" err
+'
+
+test_expect_success '--set-upstream-to to a local branch is not mistaken for a slip' '
+	git branch slip-local-upstream &&
+	git branch slip-local-target &&
+	git branch --set-upstream-to=slip-local-upstream slip-local-target 2>err &&
+	test_grep ! "Did you mean" err &&
+	echo refs/heads/slip-local-upstream >expect &&
+	git config branch.slip-local-target.merge >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--set-upstream-to slip suggestion keeps a slashed branch name' '
+	test_when_finished "git remote remove slip-remote" &&
+	git remote add slip-remote . &&
+	git update-ref refs/remotes/slip-remote/slip/feature HEAD &&
+	test_must_fail git branch --set-upstream-to slip-remote slip/feature 2>err &&
+	test_grep "hint: Did you mean to use: git branch --set-upstream-to=slip-remote/slip/feature?" err
+'
+
 test_expect_success '--set-upstream-to fails on a missing src branch' '
 	test_must_fail git branch --set-upstream-to does-not-exist main 2>err &&
 	test_grep "the requested upstream branch '"'"'does-not-exist'"'"' does not exist" err

-- 
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