threads / patch / 63684

v4, 7 partssubmodule: improve remote lookup logic

Subject: [PATCH v4 0/7] submodule: improve remote lookup logic

## tl;dr

8 messages between Jun 23, 2025 and Jun 23, 2025. Diffs are folded; open one to read it.

replies: 7people: 1as markdown or json

Jacob Keller· Jun 23, 2025, 23:11 UTC · lore

This series improves the git submodule remote lookup logic implemented in submodule--helper.

A few cleanups are done first:
* Remove the branch->merge_name array and replace it by directly using
  branch->merge[i]->src immediately. This is simpler and easier to reason
  about. While cleaning this up, also fix the issues with branch_release()
  not tearing down everything properly.
* remote_clear() failed to release the remote->push and remote->fetch
  refspec data. Fix this.
* The starts_with_dot(_dot)_slash helper functions are moved to dir.h for
  re-use, as these are used both within submodule--helper.c and
  submodule-config.c
* Several remote.c helper functions are refactored to take repository
  pointers, enabling use with a submodule repository pointer.

Next, the submodule--helper.c logic replaces the repo_get_default_remote() function with a repo_default_remote() function in remote.c, which is based on the more robust configuration reading logic. This helper uses similar logic but also allows returning the only valid remote in the case where a repository has exactly one remote. This way we do not fall back to "origin" if a user has renamed the remote without adding another.

This improved logic is a good first step, but won't handle cases where there are multiple remotes, with none of them being named "origin".

For the final improvement, notice that the parent project already stores the URL for the submodule in its .git/config or .gitmodules file. This URL is what we use to set the remote in the first place when cloning.

Add a repo_remote_from_url() helper which will iterate through the remotes and find the first remote with that URL. Use this in get_default_remote_submodule() to first try and find a remote by its URL. If unsuccessful, we still keep the original fallback logic, in the off chance that the user has changed the URL from within the submodule.

This method is more robust as it is less likely that the user has manually changed the submodule URL within the submodule but not also within the .git/config.

With this change, all commands which need the submodule remote will first look up by URL before trying to use the fallback logic, and should now be able to find a suitable remote regardless of now they are renamed.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
---
Changes in v4:
- Fix branch_has_merge_config to use branch->set_merge
- FREE_AND_NULL branch->merge in merge_clear()
- Link to v3: https://lore.kernel.org/r/20250618-jk-submodule-helper-use-url-v3-0-7c60f2679271@gmail.com
Changes in v3:
- Completely remove branch->merge_name, making the resulting logic much
  easier to understand.
- Link to v2: https://lore.kernel.org/r/20250617-jk-submodule-helper-use-url-v2-0-04cbb003177d@gmail.com
Changes in v2:
- Remove repo_get_default_remote() entirely. The extra checks it does are
  really only necessary if you're doing manual configuration lookup. This
  avoids the confusion of similarly named functions and is less code.
- Fix leaks in branch_release() and remote_clear().
- Add a forward declaration of struct repository.
- Verified tests pass with leak sanitizer now.
- Link to v1: https://lore.kernel.org/r/20250610-jk-submodule-helper-use-url-v1-0-6d14c1504e91@gmail.com
---
Jacob Keller (7):
      remote: remove branch->merge_name and fix branch_release()
      remote: fix tear down of struct remote
      dir: move starts_with_dot(_dot)_slash to dir.h
      remote: remove the_repository from some functions
      submodule--helper: improve logic for fallback remote name
      submodule: move get_default_remote_submodule()
      submodule: look up remotes by URL first
 dir.h                       |  23 +++++++
 remote.h                    |   8 ++-
 branch.c                    |   4 +-
 builtin/pull.c              |   2 +-
 builtin/submodule--helper.c | 106 ++++++++++++-------------------
 remote.c                    | 149 ++++++++++++++++++++++++++++----------------
 submodule-config.c          |  12 ----
 t/t7406-submodule-update.sh |  61 ++++++++++++++++++
 8 files changed, 230 insertions(+), 135 deletions(-)
---
base-commit: 16bd9f20a403117f2e0d9bcda6c6e621d3763e77
change-id: 20250610-jk-submodule-helper-use-url-e55d3c379faf
Best regards,
-- 
Jacob Keller <jacob.keller@gmail.com>
Jacob Keller· Jun 23, 2025, 23:11 UTC · re: Jacob Keller · lore

[PATCH v4 1/7] remote: remove branch->merge_name and fix branch_release()

From: Jacob Keller <jacob.keller@gmail.com>

The branch structure has both branch->merge_name and branch->merge for tracking the merge information. The former is allocated by add_merge() and stores the names read from the configuration file. The latter is allocated by set_merge() which is called by branch_get() when an external caller requests a branch.

This leads to the confusing situation where branch->merge_nr tracks both the size of branch->merge (once its allocated) and branch->merge_name. The branch_release() function incorrectly assumes that branch->merge is always set when branch->merge_nr is non-zero, and can potentially crash if read_config() is called without branch_get() being called on every branch.

In addition, branch_release() fails to free some of the memory associated with the structure including:

 * Failure to free the refspec_item containers in branch->merge[i]
 * Failure to free the strings in branch->merge_name[i]
 * Failure to free the branch->merge_name parent array.

The set_merge() function sets branch->merge_nr to 0 when there is no valid remote_name, to avoid external callers seeing a non-zero merge_nr but a NULL merge array. This results in failure to release most of the merge data as well.

These issues could be fixed directly, and indeed I initially proposed such a change at [1] in the past. While this works, there was some confusion during review because of the inconsistencies.

Instead, its time to clean up the situation properly. Remove branch->merge_name entirely. Instead, allocate branch->merge earlier within add_merge() instead of within set_merge(). Instead of having set_merge() copy from merge_name[i] to merge[i]->src, just have add_merge() directly initialize merge[i]->src.

Modify the add_merge() to call xstrdup() itself, instead of having the caller of add_merge() do so. This makes it more obvious which code owns the memory.

Update all callers which use branch->merge_name[i] to use branch->merge[i]->src instead.

Add a merge_clear() function which properly releases all of the merge-related memory, and which sets branch->merge_nr to zero. Use this both in branch_release() and in set_merge(), fixing the leak when set_merge() finds no valid remote_name.

Add a set_merge variable to the branch structure, which indicates whether set_merge() has been called. This replaces the previous use of a NULL check against the branch->merge array.

With these changes, the merge array is always allocated when merge_nr is non-zero.

This use of refspec_item to store the names should be safe. External callers should be using branch_get() to obtain a pointer to the branch, which will call set_merge(), and the callers internal to remote.c already handle the partially initialized refpsec_item structure safely.

This end result is cleaner, and avoids duplicating the merge names twice.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Link: [1] https://lore.kernel.org/git/20250617-jk-submodule-helper-use-url-v2-1-04cbb003177d@gmail.com/
---
 remote.h       |  4 ++--
 branch.c       |  4 ++--
 builtin/pull.c |  2 +-
 remote.c       | 44 ++++++++++++++++++++++++++++----------------
 4 files changed, 33 insertions(+), 21 deletions(-)
Show changes to 4 files +33 −21

remote.h, branch.c, builtin/pull.c, remote.c

diff --git a/remote.h b/remote.h
index 7e4943ae3a70ecefa3332d211084762ca30b59b6..76d93bf88d1fb8c0e2cbc2bc99558f23a256155c 100644
--- a/remote.h
+++ b/remote.h
@@ -315,8 +315,8 @@ struct branch {
 
 	char *pushremote_name;
 
-	/* An array of the "merge" lines in the configuration. */
-	const char **merge_name;
+	/* True if set_merge() has been called to finalize the merge array */
+	int set_merge;
 
 	/**
 	 * An array of the struct refspecs used for the merge lines. That is,
diff --git a/branch.c b/branch.c
index 6d01d7d6bdb2e4d969429433b1b6bc88446a96c5..93f5b4e8dd9fe53ae4412827c458bade7c341278 100644
--- a/branch.c
+++ b/branch.c
@@ -230,7 +230,7 @@ static int inherit_tracking(struct tracking *tracking, const char *orig_ref)
 		return -1;
 	}
 
-	if (branch->merge_nr < 1 || !branch->merge_name || !branch->merge_name[0]) {
+	if (branch->merge_nr < 1 || !branch->merge || !branch->merge[0] || !branch->merge[0]->src) {
 		warning(_("asked to inherit tracking from '%s', but no merge configuration is set"),
 			bare_ref);
 		return -1;
@@ -238,7 +238,7 @@ static int inherit_tracking(struct tracking *tracking, const char *orig_ref)
 
 	tracking->remote = branch->remote_name;
 	for (i = 0; i < branch->merge_nr; i++)
-		string_list_append(tracking->srcs, branch->merge_name[i]);
+		string_list_append(tracking->srcs, branch->merge[i]->src);
 	return 0;
 }
 
diff --git a/builtin/pull.c b/builtin/pull.c
index a1ebc6ad3328e074b105246f6bf5c41b063c17c9..f4556ae155ce22ea91f9878d772eb9228fe4e604 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -487,7 +487,7 @@ static void NORETURN die_no_merge_candidates(const char *repo, const char **refs
 	} else
 		fprintf_ln(stderr, _("Your configuration specifies to merge with the ref '%s'\n"
 			"from the remote, but no such ref was fetched."),
-			*curr_branch->merge_name);
+			curr_branch->merge[0]->src);
 	exit(1);
 }
 
diff --git a/remote.c b/remote.c
index 4099183cacdc8a607a8b5eaec86e456b2ef46b48..ee95126f3f20080a932b82314e8017e277569cc1 100644
--- a/remote.c
+++ b/remote.c
@@ -174,9 +174,15 @@ static void remote_clear(struct remote *remote)
 
 static void add_merge(struct branch *branch, const char *name)
 {
-	ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
+	struct refspec_item *merge;
+
+	ALLOC_GROW(branch->merge, branch->merge_nr + 1,
 		   branch->merge_alloc);
-	branch->merge_name[branch->merge_nr++] = name;
+
+	merge = xcalloc(1, sizeof(*merge));
+	merge->src = xstrdup(name);
+
+	branch->merge[branch->merge_nr++] = merge;
 }
 
 struct branches_hash_key {
@@ -247,15 +253,23 @@ static struct branch *make_branch(struct remote_state *remote_state,
 	return ret;
 }
 
+static void merge_clear(struct branch *branch)
+{
+	for (int i = 0; i < branch->merge_nr; i++) {
+		refspec_item_clear(branch->merge[i]);
+		free(branch->merge[i]);
+	}
+	FREE_AND_NULL(branch->merge);
+	branch->merge_nr = 0;
+}
+
 static void branch_release(struct branch *branch)
 {
 	free((char *)branch->name);
 	free((char *)branch->refname);
 	free(branch->remote_name);
 	free(branch->pushremote_name);
-	for (int i = 0; i < branch->merge_nr; i++)
-		refspec_item_clear(branch->merge[i]);
-	free(branch->merge);
+	merge_clear(branch);
 }
 
 static struct rewrite *make_rewrite(struct rewrites *r,
@@ -429,7 +443,7 @@ static int handle_config(const char *key, const char *value,
 		} else if (!strcmp(subkey, "merge")) {
 			if (!value)
 				return config_error_nonbool(key);
-			add_merge(branch, xstrdup(value));
+			add_merge(branch, value);
 		}
 		return 0;
 	}
@@ -692,7 +706,7 @@ char *remote_ref_for_branch(struct branch *branch, int for_push)
 	if (branch) {
 		if (!for_push) {
 			if (branch->merge_nr) {
-				return xstrdup(branch->merge_name[0]);
+				return xstrdup(branch->merge[0]->src);
 			}
 		} else {
 			char *dst;
@@ -1731,32 +1745,30 @@ static void set_merge(struct remote_state *remote_state, struct branch *ret)
 
 	if (!ret)
 		return; /* no branch */
-	if (ret->merge)
+	if (ret->set_merge)
 		return; /* already run */
 	if (!ret->remote_name || !ret->merge_nr) {
 		/*
 		 * no merge config; let's make sure we don't confuse callers
 		 * with a non-zero merge_nr but a NULL merge
 		 */
-		ret->merge_nr = 0;
+		merge_clear(ret);
 		return;
 	}
+	ret->set_merge = 1;
 
 	remote = remotes_remote_get(remote_state, ret->remote_name);
 
-	CALLOC_ARRAY(ret->merge, ret->merge_nr);
 	for (i = 0; i < ret->merge_nr; i++) {
-		ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
-		ret->merge[i]->src = xstrdup(ret->merge_name[i]);
 		if (!remote_find_tracking(remote, ret->merge[i]) ||
 		    strcmp(ret->remote_name, "."))
 			continue;
-		if (repo_dwim_ref(the_repository, ret->merge_name[i],
-				  strlen(ret->merge_name[i]), &oid, &ref,
+		if (repo_dwim_ref(the_repository, ret->merge[i]->src,
+				  strlen(ret->merge[i]->src), &oid, &ref,
 				  0) == 1)
 			ret->merge[i]->dst = ref;
 		else
-			ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
+			ret->merge[i]->dst = xstrdup(ret->merge[i]->src);
 	}
 }
 
@@ -1776,7 +1788,7 @@ struct branch *branch_get(const char *name)
 
 int branch_has_merge_config(struct branch *branch)
 {
-	return branch && !!branch->merge;
+	return branch && branch->set_merge;
 }
 
 int branch_merge_matches(struct branch *branch,

-- 
2.48.1.397.gec9d649cc640
Jacob Keller· Jun 23, 2025, 23:11 UTC · re: Jacob Keller · lore

[PATCH v4 3/7] dir: move starts_with_dot(_dot)_slash to dir.h

From: Jacob Keller <jacob.keller@gmail.com>

Both submodule--helper.c and submodule-config.c have an implementation of starts_with_dot_slash and starts_with_dot_dot_slash. The dir.h header has starts_with_dot(_dot)_slash_native, which sets PATH_MATCH_NATIVE.

Move the helpers to dir.h as static inlines. I thought about renaming them to postfix with _platform but that felt too long and ugly. On the other hand it might be slightly confusing with _native.

This simplifies a submodule refactor which wants to use the helpers earlier in the submodule--helper.c file.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
---
 dir.h                       | 23 +++++++++++++++++++++++
 builtin/submodule--helper.c | 12 ------------
 submodule-config.c          | 12 ------------
 3 files changed, 23 insertions(+), 24 deletions(-)
Show changes to 3 files +23 −24

dir.h, builtin/submodule--helper.c, submodule-config.c

diff --git a/dir.h b/dir.h
index d7e71aa8daa7d833e4c05e6875b997bc321c6070..fc9be7b427a134e46bcd66c8df42375db47727fc 100644
--- a/dir.h
+++ b/dir.h
@@ -676,4 +676,27 @@ static inline int starts_with_dot_dot_slash_native(const char *const path)
 	return path_match_flags(path, what | PATH_MATCH_NATIVE);
 }
 
+/**
+ * starts_with_dot_slash: convenience wrapper for
+ * patch_match_flags() with PATH_MATCH_STARTS_WITH_DOT_SLASH and
+ * PATH_MATCH_XPLATFORM.
+ */
+static inline int starts_with_dot_slash(const char *const path)
+{
+	const enum path_match_flags what = PATH_MATCH_STARTS_WITH_DOT_SLASH;
+
+	return path_match_flags(path, what | PATH_MATCH_XPLATFORM);
+}
+
+/**
+ * starts_with_dot_dot_slash: convenience wrapper for
+ * patch_match_flags() with PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH and
+ * PATH_MATCH_XPLATFORM.
+ */
+static inline int starts_with_dot_dot_slash(const char *const path)
+{
+	const enum path_match_flags what = PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH;
+
+	return path_match_flags(path, what | PATH_MATCH_XPLATFORM);
+}
 #endif
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 53da2116ddf576bc565b29f043e8b703b8b1563b..9e8cdfe1b2a8c2985d9c1b8ad6f1b0d1f9401714 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -438,18 +438,6 @@ static int module_foreach(int argc, const char **argv, const char *prefix,
 	return ret;
 }
 
-static int starts_with_dot_slash(const char *const path)
-{
-	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_SLASH |
-				PATH_MATCH_XPLATFORM);
-}
-
-static int starts_with_dot_dot_slash(const char *const path)
-{
-	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH |
-				PATH_MATCH_XPLATFORM);
-}
-
 struct init_cb {
 	const char *prefix;
 	const char *super_prefix;
diff --git a/submodule-config.c b/submodule-config.c
index 8630e27947d3943e1980eb7a53bd41a546842503..d64438b2a18ed2123cc5e18f739539209032d3e9 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -235,18 +235,6 @@ int check_submodule_name(const char *name)
 	return 0;
 }
 
-static int starts_with_dot_slash(const char *const path)
-{
-	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_SLASH |
-				PATH_MATCH_XPLATFORM);
-}
-
-static int starts_with_dot_dot_slash(const char *const path)
-{
-	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH |
-				PATH_MATCH_XPLATFORM);
-}
-
 static int submodule_url_is_relative(const char *url)
 {
 	return starts_with_dot_slash(url) || starts_with_dot_dot_slash(url);

-- 
2.48.1.397.gec9d649cc640
Jacob Keller· Jun 23, 2025, 23:11 UTC · re: Jacob Keller · lore

[PATCH v4 2/7] remote: fix tear down of struct remote

From: Jacob Keller <jacob.keller@gmail.com>

The remote_clear() function failed to free the remote->push and remote->fetch refspec fields.

This should be caught by the leak sanitizer. However, for callers which use ``the_repository``, the values never go out of scope and the sanitizer doesn't complain.

A future change is going to add a caller of read_config() for a submodule repository structure, which would result in the leak sanitizer complaining.

Fix remote_clear(), updating it to properly call refspec_clear() for both the push and fetch members.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
---
 remote.c | 3 +++
 1 file changed, 3 insertions(+)
Show changes to remote.c +3 −0
diff --git a/remote.c b/remote.c
index ee95126f3f20080a932b82314e8017e277569cc1..194bb447784ac1f71fb85a9fed3312e7458a9d5d 100644
--- a/remote.c
+++ b/remote.c
@@ -165,6 +165,9 @@ static void remote_clear(struct remote *remote)
 	strvec_clear(&remote->url);
 	strvec_clear(&remote->pushurl);
 
+	refspec_clear(&remote->push);
+	refspec_clear(&remote->fetch);
+
 	free((char *)remote->receivepack);
 	free((char *)remote->uploadpack);
 	FREE_AND_NULL(remote->http_proxy);

-- 
2.48.1.397.gec9d649cc640
Jacob Keller· Jun 23, 2025, 23:11 UTC · re: Jacob Keller · lore

[PATCH v4 4/7] remote: remove the_repository from some functions

From: Jacob Keller <jacob.keller@gmail.com>

The remotes_remote_get_1 (and its caller, remotes_remote_get, have an implicit dependency on the_repository due to calling read_branches_file() and read_remotes_file(), both of which use the_repository. The branch_get() function calls set_merge() which has an implicit dependency on the_repository as well.

Because of this use of the_repository, the helper functions cannot be used in code paths which operate on other repositories. A future refactor of the submodule--helper will want to make use of some of these functions.

Refactor to break the dependency by passing struct repository *repo instead of struct remote_state *remote_state in a few places.

The public callers and many other helper functions still depend on the_repository. A repo-aware function will be exposed in a following change for git submodule--helper.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
---
 remote.c | 58 ++++++++++++++++++++++++++++------------------------------
 1 file changed, 28 insertions(+), 30 deletions(-)
Show changes to remote.c +28 −30
diff --git a/remote.c b/remote.c
index 194bb447784ac1f71fb85a9fed3312e7458a9d5d..e7ff21dc0340fd81b0c0c21c9d2199c3c0d53946 100644
--- a/remote.c
+++ b/remote.c
@@ -334,11 +334,10 @@ static void warn_about_deprecated_remote_type(const char *type,
 		type, remote->name, remote->name, remote->name);
 }
 
-static void read_remotes_file(struct remote_state *remote_state,
-			      struct remote *remote)
+static void read_remotes_file(struct repository *repo, struct remote *remote)
 {
 	struct strbuf buf = STRBUF_INIT;
-	FILE *f = fopen_or_warn(repo_git_path_append(the_repository, &buf,
+	FILE *f = fopen_or_warn(repo_git_path_append(repo, &buf,
 						     "remotes/%s", remote->name), "r");
 
 	if (!f)
@@ -354,7 +353,7 @@ static void read_remotes_file(struct remote_state *remote_state,
 		strbuf_rtrim(&buf);
 
 		if (skip_prefix(buf.buf, "URL:", &v))
-			add_url_alias(remote_state, remote,
+			add_url_alias(repo->remote_state, remote,
 				      skip_spaces(v));
 		else if (skip_prefix(buf.buf, "Push:", &v))
 			refspec_append(&remote->push, skip_spaces(v));
@@ -367,12 +366,11 @@ static void read_remotes_file(struct remote_state *remote_state,
 	strbuf_release(&buf);
 }
 
-static void read_branches_file(struct remote_state *remote_state,
-			       struct remote *remote)
+static void read_branches_file(struct repository *repo, struct remote *remote)
 {
 	char *frag, *to_free = NULL;
 	struct strbuf buf = STRBUF_INIT;
-	FILE *f = fopen_or_warn(repo_git_path_append(the_repository, &buf,
+	FILE *f = fopen_or_warn(repo_git_path_append(repo, &buf,
 						     "branches/%s", remote->name), "r");
 
 	if (!f)
@@ -399,9 +397,9 @@ static void read_branches_file(struct remote_state *remote_state,
 	if (frag)
 		*(frag++) = '\0';
 	else
-		frag = to_free = repo_default_branch_name(the_repository, 0);
+		frag = to_free = repo_default_branch_name(repo, 0);
 
-	add_url_alias(remote_state, remote, buf.buf);
+	add_url_alias(repo->remote_state, remote, buf.buf);
 	refspec_appendf(&remote->fetch, "refs/heads/%s:refs/heads/%s",
 			frag, remote->name);
 
@@ -698,7 +696,7 @@ const char *pushremote_for_branch(struct branch *branch, int *explicit)
 					     branch, explicit);
 }
 
-static struct remote *remotes_remote_get(struct remote_state *remote_state,
+static struct remote *remotes_remote_get(struct repository *repo,
 					 const char *name);
 
 char *remote_ref_for_branch(struct branch *branch, int for_push)
@@ -717,7 +715,7 @@ char *remote_ref_for_branch(struct branch *branch, int for_push)
 					the_repository->remote_state, branch,
 					NULL);
 			struct remote *remote = remotes_remote_get(
-				the_repository->remote_state, remote_name);
+				the_repository, remote_name);
 
 			if (remote && remote->push.nr &&
 			    (dst = apply_refspecs(&remote->push,
@@ -774,10 +772,11 @@ static void validate_remote_url(struct remote *remote)
 }
 
 static struct remote *
-remotes_remote_get_1(struct remote_state *remote_state, const char *name,
+remotes_remote_get_1(struct repository *repo, const char *name,
 		     const char *(*get_default)(struct remote_state *,
 						struct branch *, int *))
 {
+	struct remote_state *remote_state = repo->remote_state;
 	struct remote *ret;
 	int name_given = 0;
 
@@ -791,9 +790,9 @@ remotes_remote_get_1(struct remote_state *remote_state, const char *name,
 #ifndef WITH_BREAKING_CHANGES
 	if (valid_remote_nick(name) && have_git_dir()) {
 		if (!valid_remote(ret))
-			read_remotes_file(remote_state, ret);
+			read_remotes_file(repo, ret);
 		if (!valid_remote(ret))
-			read_branches_file(remote_state, ret);
+			read_branches_file(repo, ret);
 	}
 #endif /* WITH_BREAKING_CHANGES */
 	if (name_given && !valid_remote(ret))
@@ -807,35 +806,33 @@ remotes_remote_get_1(struct remote_state *remote_state, const char *name,
 }
 
 static inline struct remote *
-remotes_remote_get(struct remote_state *remote_state, const char *name)
+remotes_remote_get(struct repository *repo, const char *name)
 {
-	return remotes_remote_get_1(remote_state, name,
-				    remotes_remote_for_branch);
+	return remotes_remote_get_1(repo, name, remotes_remote_for_branch);
 }
 
 struct remote *remote_get(const char *name)
 {
 	read_config(the_repository, 0);
-	return remotes_remote_get(the_repository->remote_state, name);
+	return remotes_remote_get(the_repository, name);
 }
 
 struct remote *remote_get_early(const char *name)
 {
 	read_config(the_repository, 1);
-	return remotes_remote_get(the_repository->remote_state, name);
+	return remotes_remote_get(the_repository, name);
 }
 
 static inline struct remote *
-remotes_pushremote_get(struct remote_state *remote_state, const char *name)
+remotes_pushremote_get(struct repository *repo, const char *name)
 {
-	return remotes_remote_get_1(remote_state, name,
-				    remotes_pushremote_for_branch);
+	return remotes_remote_get_1(repo, name, remotes_pushremote_for_branch);
 }
 
 struct remote *pushremote_get(const char *name)
 {
 	read_config(the_repository, 0);
-	return remotes_pushremote_get(the_repository->remote_state, name);
+	return remotes_pushremote_get(the_repository, name);
 }
 
 int remote_is_configured(struct remote *remote, int in_repo)
@@ -1739,7 +1736,7 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
 	}
 }
 
-static void set_merge(struct remote_state *remote_state, struct branch *ret)
+static void set_merge(struct repository *repo, struct branch *ret)
 {
 	struct remote *remote;
 	char *ref;
@@ -1760,13 +1757,13 @@ static void set_merge(struct remote_state *remote_state, struct branch *ret)
 	}
 	ret->set_merge = 1;
 
-	remote = remotes_remote_get(remote_state, ret->remote_name);
+	remote = remotes_remote_get(repo, ret->remote_name);
 
 	for (i = 0; i < ret->merge_nr; i++) {
 		if (!remote_find_tracking(remote, ret->merge[i]) ||
 		    strcmp(ret->remote_name, "."))
 			continue;
-		if (repo_dwim_ref(the_repository, ret->merge[i]->src,
+		if (repo_dwim_ref(repo, ret->merge[i]->src,
 				  strlen(ret->merge[i]->src), &oid, &ref,
 				  0) == 1)
 			ret->merge[i]->dst = ref;
@@ -1785,7 +1782,7 @@ struct branch *branch_get(const char *name)
 	else
 		ret = make_branch(the_repository->remote_state, name,
 				  strlen(name));
-	set_merge(the_repository->remote_state, ret);
+	set_merge(the_repository, ret);
 	return ret;
 }
 
@@ -1856,13 +1853,14 @@ static const char *tracking_for_push_dest(struct remote *remote,
 	return ret;
 }
 
-static const char *branch_get_push_1(struct remote_state *remote_state,
+static const char *branch_get_push_1(struct repository *repo,
 				     struct branch *branch, struct strbuf *err)
 {
+	struct remote_state *remote_state = repo->remote_state;
 	struct remote *remote;
 
 	remote = remotes_remote_get(
-		remote_state,
+		repo,
 		remotes_pushremote_for_branch(remote_state, branch, NULL));
 	if (!remote)
 		return error_buf(err,
@@ -1929,7 +1927,7 @@ const char *branch_get_push(struct branch *branch, struct strbuf *err)
 
 	if (!branch->push_tracking_ref)
 		branch->push_tracking_ref = branch_get_push_1(
-			the_repository->remote_state, branch, err);
+			the_repository, branch, err);
 	return branch->push_tracking_ref;
 }
 

-- 
2.48.1.397.gec9d649cc640
Jacob Keller· Jun 23, 2025, 23:11 UTC · re: Jacob Keller · lore

[PATCH v4 5/7] submodule--helper: improve logic for fallback remote name

From: Jacob Keller <jacob.keller@gmail.com>

The repo_get_default_remote() function in submodule--helper currently tries to figure out the proper remote name to use for a submodule based on a few factors.

First, it tries to find the remote for the currently checked out branch. This works if the submodule is configured to checkout to a branch instead of a detached HEAD state.

In the detached HEAD state, the code calls back to using "origin", on the assumption that this is the default remote name. Some users may change this, such as by setting clone.defaultRemoteName, or by changing the remote name manually within the submodule repository.

As a first step to improving this situation, refactor to reuse the logic from remotes_remote_for_branch(). This function uses the remote from the branch if it has one. If it doesn't then it checks to see if there is exactly one remote. It uses this remote first before attempting to fall back to "origin".

To allow using this helper function, introduce a repo_default_remote() helper to remote.c which takes a repository structure. This helper will load the remote configuration and get the "HEAD" branch. Then it will call remotes_remote_for_branch to find the default remote.

Replace calls of repo_get_default_remote() with the calls to this new function. To maintain consistency with the existing callers, continue copying the returned string with xstrdup.

This isn't a perfect solution for users who change remote names, but it should help in cases where the remote name is changed but users haven't added any additional remotes.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
---
 remote.h                    |  3 +++
 builtin/submodule--helper.c | 46 +++++----------------------------------------
 remote.c                    | 25 +++++++++++++++++++-----
 t/t7406-submodule-update.sh | 29 ++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+), 46 deletions(-)
Show changes to 4 files +57 −46

remote.h, builtin/submodule--helper.c, remote.c, t/t7406-submodule-update.sh

diff --git a/remote.h b/remote.h
index 76d93bf88d1fb8c0e2cbc2bc99558f23a256155c..8dc5cfa49ef78808348a84c9b3f416b31cd3bbd7 100644
--- a/remote.h
+++ b/remote.h
@@ -9,6 +9,7 @@
 
 struct option;
 struct transport_ls_refs_options;
+struct repository;
 
 /**
  * The API gives access to the configuration related to remotes. It handles
@@ -338,6 +339,8 @@ const char *remote_for_branch(struct branch *branch, int *explicit);
 const char *pushremote_for_branch(struct branch *branch, int *explicit);
 char *remote_ref_for_branch(struct branch *branch, int for_push);
 
+const char *repo_default_remote(struct repository *repo);
+
 /* returns true if the given branch has merge configuration given. */
 int branch_has_merge_config(struct branch *branch);
 
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 9e8cdfe1b2a8c2985d9c1b8ad6f1b0d1f9401714..4aa237033a526fca29cce2926419462179d40ee3 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -41,61 +41,25 @@
 typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
 				  void *cb_data);
 
-static int repo_get_default_remote(struct repository *repo, char **default_remote)
-{
-	char *dest = NULL;
-	struct strbuf sb = STRBUF_INIT;
-	struct ref_store *store = get_main_ref_store(repo);
-	const char *refname = refs_resolve_ref_unsafe(store, "HEAD", 0, NULL,
-						      NULL);
-
-	if (!refname)
-		return die_message(_("No such ref: %s"), "HEAD");
-
-	/* detached HEAD */
-	if (!strcmp(refname, "HEAD")) {
-		*default_remote = xstrdup("origin");
-		return 0;
-	}
-
-	if (!skip_prefix(refname, "refs/heads/", &refname))
-		return die_message(_("Expecting a full ref name, got %s"),
-				   refname);
-
-	strbuf_addf(&sb, "branch.%s.remote", refname);
-	if (repo_config_get_string(repo, sb.buf, &dest))
-		*default_remote = xstrdup("origin");
-	else
-		*default_remote = dest;
-
-	strbuf_release(&sb);
-	return 0;
-}
-
 static int get_default_remote_submodule(const char *module_path, char **default_remote)
 {
 	struct repository subrepo;
-	int ret;
 
 	if (repo_submodule_init(&subrepo, the_repository, module_path,
 				null_oid(the_hash_algo)) < 0)
 		return die_message(_("could not get a repository handle for submodule '%s'"),
 				   module_path);
-	ret = repo_get_default_remote(&subrepo, default_remote);
+
+	*default_remote = xstrdup(repo_default_remote(&subrepo));
+
 	repo_clear(&subrepo);
 
-	return ret;
+	return 0;
 }
 
 static char *get_default_remote(void)
 {
-	char *default_remote;
-	int code = repo_get_default_remote(the_repository, &default_remote);
-
-	if (code)
-		exit(code);
-
-	return default_remote;
+	return xstrdup(repo_default_remote(the_repository));
 }
 
 static char *resolve_relative_url(const char *rel_url, const char *up_path, int quiet)
diff --git a/remote.c b/remote.c
index e7ff21dc0340fd81b0c0c21c9d2199c3c0d53946..e35cf7ec61ac946d1e84c5a0ae309e63c66d0335 100644
--- a/remote.c
+++ b/remote.c
@@ -1772,20 +1772,35 @@ static void set_merge(struct repository *repo, struct branch *ret)
 	}
 }
 
-struct branch *branch_get(const char *name)
+static struct branch *repo_branch_get(struct repository *repo, const char *name)
 {
 	struct branch *ret;
 
-	read_config(the_repository, 0);
+	read_config(repo, 0);
 	if (!name || !*name || !strcmp(name, "HEAD"))
-		ret = the_repository->remote_state->current_branch;
+		ret = repo->remote_state->current_branch;
 	else
-		ret = make_branch(the_repository->remote_state, name,
+		ret = make_branch(repo->remote_state, name,
 				  strlen(name));
-	set_merge(the_repository, ret);
+	set_merge(repo, ret);
 	return ret;
 }
 
+struct branch *branch_get(const char *name)
+{
+	return repo_branch_get(the_repository, name);
+}
+
+const char *repo_default_remote(struct repository *repo)
+{
+	struct branch *branch;
+
+	read_config(repo, 0);
+	branch = repo_branch_get(repo, "HEAD");
+
+	return remotes_remote_for_branch(repo->remote_state, branch, NULL);
+}
+
 int branch_has_merge_config(struct branch *branch)
 {
 	return branch && branch->set_merge;
diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
index c562bad042ab2d4d0f82cb8b57a1eadbe24044d1..748b529745a5121f121768bb4e0cbc11bc833ea4 100755
--- a/t/t7406-submodule-update.sh
+++ b/t/t7406-submodule-update.sh
@@ -1134,6 +1134,35 @@ test_expect_success 'setup clean recursive superproject' '
 	git clone --recurse-submodules top top-clean
 '
 
+test_expect_success 'submodule update with renamed remote' '
+	test_when_finished "rm -fr top-cloned" &&
+	cp -r top-clean top-cloned &&
+
+	# Create a commit in each repo, starting with bottom
+	test_commit -C bottom rename_commit &&
+	# Create middle commit
+	git -C middle/bottom fetch &&
+	git -C middle/bottom checkout -f FETCH_HEAD &&
+	git -C middle add bottom &&
+	git -C middle commit -m "rename_commit" &&
+	# Create top commit
+	git -C top/middle fetch &&
+	git -C top/middle checkout -f FETCH_HEAD &&
+	git -C top add middle &&
+	git -C top commit -m "rename_commit" &&
+
+	# rename the submodule remote
+	git -C top-cloned/middle remote rename origin upstream &&
+
+	# Make the update of "middle" a no-op, otherwise we error out
+	# because of its unmerged state
+	test_config -C top-cloned submodule.middle.update !true &&
+	git -C top-cloned submodule update --recursive 2>actual.err &&
+	cat >expect.err <<-\EOF &&
+	EOF
+	test_cmp expect.err actual.err
+'
+
 test_expect_success 'submodule update should skip unmerged submodules' '
 	test_when_finished "rm -fr top-cloned" &&
 	cp -r top-clean top-cloned &&

-- 
2.48.1.397.gec9d649cc640
Jacob Keller· Jun 23, 2025, 23:11 UTC · re: Jacob Keller · lore

[PATCH v4 6/7] submodule: move get_default_remote_submodule()

From: Jacob Keller <jacob.keller@gmail.com>

A future refactor got get_default_remote_submodule() is going to depend on resolve_relative_url(). That function depends on get_default_remote().

Move get_default_remote_submodule() after resolve_relative_url() first to make the additional functionality easier to review.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
---
 builtin/submodule--helper.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)
Show changes to builtin/submodule--helper.c +16 −16
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 4aa237033a526fca29cce2926419462179d40ee3..1aa87435c2000e94f43da94c5ef88a307f6f3f4a 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -41,22 +41,6 @@
 typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
 				  void *cb_data);
 
-static int get_default_remote_submodule(const char *module_path, char **default_remote)
-{
-	struct repository subrepo;
-
-	if (repo_submodule_init(&subrepo, the_repository, module_path,
-				null_oid(the_hash_algo)) < 0)
-		return die_message(_("could not get a repository handle for submodule '%s'"),
-				   module_path);
-
-	*default_remote = xstrdup(repo_default_remote(&subrepo));
-
-	repo_clear(&subrepo);
-
-	return 0;
-}
-
 static char *get_default_remote(void)
 {
 	return xstrdup(repo_default_remote(the_repository));
@@ -86,6 +70,22 @@ static char *resolve_relative_url(const char *rel_url, const char *up_path, int
 	return resolved_url;
 }
 
+static int get_default_remote_submodule(const char *module_path, char **default_remote)
+{
+	struct repository subrepo;
+
+	if (repo_submodule_init(&subrepo, the_repository, module_path,
+				null_oid(the_hash_algo)) < 0)
+		return die_message(_("could not get a repository handle for submodule '%s'"),
+				   module_path);
+
+	*default_remote = xstrdup(repo_default_remote(&subrepo));
+
+	repo_clear(&subrepo);
+
+	return 0;
+}
+
 /* the result should be freed by the caller. */
 static char *get_submodule_displaypath(const char *path, const char *prefix,
 				       const char *super_prefix)

-- 
2.48.1.397.gec9d649cc640
Jacob Keller· Jun 23, 2025, 23:11 UTC · re: Jacob Keller · lore

[PATCH v4 7/7] submodule: look up remotes by URL first

From: Jacob Keller <jacob.keller@gmail.com>

The get_default_remote_submodule() function performs a lookup to find the appropriate remote to use within a submodule. The function first checks to see if it can find the remote for the current branch. If this fails, it then checks to see if there is exactly one remote. It will use this, before finally falling back to "origin" as the default.

If a user happens to rename their default remote from origin, either manually or by setting something like clone.defaultRemoteName, this fallback will not work.

In such cases, the submodule logic will try to use a non-existent remote. This usually manifests as a failure to trigger the submodule update.

The parent project already knows and stores the submodule URL in either .gitmodules or its .git/config.

Add a new repo_remote_from_url() helper which will iterate over all the remotes in a repository and return the first remote which has a matching URL.

Refactor get_default_remote_submodule to find the submodule and get its URL. If a valid URL exists, first try to obtain a remote using the new repo_remote_from_url(). Fall back to the repo_default_remote() otherwise.

The fallback logic is kept in case for some reason the user has manually changed the URL within the submodule. Additionally, we still try to use a remote rather than directly passing the URL in the fetch_in_submodule() logic. This ensures that an update will properly update the remote refs within the submodule as expected, rather than just fetching into FETCH_HEAD.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
---
 remote.h                    |  1 +
 builtin/submodule--helper.c | 26 +++++++++++++++++++++++++-
 remote.c                    | 15 +++++++++++++++
 t/t7406-submodule-update.sh | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 73 insertions(+), 1 deletion(-)
Show changes to 4 files +73 −1

remote.h, builtin/submodule--helper.c, remote.c, t/t7406-submodule-update.sh

diff --git a/remote.h b/remote.h
index 8dc5cfa49ef78808348a84c9b3f416b31cd3bbd7..0ca399e1835bf1829054d8937d95e5625c38d881 100644
--- a/remote.h
+++ b/remote.h
@@ -340,6 +340,7 @@ const char *pushremote_for_branch(struct branch *branch, int *explicit);
 char *remote_ref_for_branch(struct branch *branch, int for_push);
 
 const char *repo_default_remote(struct repository *repo);
+const char *repo_remote_from_url(struct repository *repo, const char *url);
 
 /* returns true if the given branch has merge configuration given. */
 int branch_has_merge_config(struct branch *branch);
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 1aa87435c2000e94f43da94c5ef88a307f6f3f4a..84a96d300d9489706fb16280f03aea02f87f1657 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -72,16 +72,40 @@ static char *resolve_relative_url(const char *rel_url, const char *up_path, int
 
 static int get_default_remote_submodule(const char *module_path, char **default_remote)
 {
+	const struct submodule *sub;
 	struct repository subrepo;
+	const char *remote_name = NULL;
+	char *url = NULL;
+
+	sub = submodule_from_path(the_repository, null_oid(the_hash_algo), module_path);
+	if (sub && sub->url) {
+		url = xstrdup(sub->url);
+
+		/* Possibly a url relative to parent */
+		if (starts_with_dot_dot_slash(url) ||
+		    starts_with_dot_slash(url)) {
+			char *oldurl = url;
+
+			url = resolve_relative_url(oldurl, NULL, 1);
+			free(oldurl);
+		}
+	}
 
 	if (repo_submodule_init(&subrepo, the_repository, module_path,
 				null_oid(the_hash_algo)) < 0)
 		return die_message(_("could not get a repository handle for submodule '%s'"),
 				   module_path);
 
-	*default_remote = xstrdup(repo_default_remote(&subrepo));
+	/* Look up by URL first */
+	if (url)
+		remote_name = repo_remote_from_url(&subrepo, url);
+	if (!remote_name)
+		remote_name = repo_default_remote(&subrepo);
+
+	*default_remote = xstrdup(remote_name);
 
 	repo_clear(&subrepo);
+	free(url);
 
 	return 0;
 }
diff --git a/remote.c b/remote.c
index e35cf7ec61ac946d1e84c5a0ae309e63c66d0335..60b4aec3dee3847b3a7b5be0f1acd9a52c60c71d 100644
--- a/remote.c
+++ b/remote.c
@@ -1801,6 +1801,21 @@ const char *repo_default_remote(struct repository *repo)
 	return remotes_remote_for_branch(repo->remote_state, branch, NULL);
 }
 
+const char *repo_remote_from_url(struct repository *repo, const char *url)
+{
+	read_config(repo, 0);
+
+	for (int i = 0; i < repo->remote_state->remotes_nr; i++) {
+		struct remote *remote = repo->remote_state->remotes[i];
+		if (!remote)
+			continue;
+
+		if (remote_has_url(remote, url))
+			return remote->name;
+	}
+	return NULL;
+}
+
 int branch_has_merge_config(struct branch *branch)
 {
 	return branch && branch->set_merge;
diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
index 748b529745a5121f121768bb4e0cbc11bc833ea4..c09047b5f441a73a02a9fc4197e9a0ea8f39b529 100755
--- a/t/t7406-submodule-update.sh
+++ b/t/t7406-submodule-update.sh
@@ -1134,6 +1134,38 @@ test_expect_success 'setup clean recursive superproject' '
 	git clone --recurse-submodules top top-clean
 '
 
+test_expect_success 'submodule update with multiple remotes' '
+	test_when_finished "rm -fr top-cloned" &&
+	cp -r top-clean top-cloned &&
+
+	# Create a commit in each repo, starting with bottom
+	test_commit -C bottom multiple_remote_commit &&
+	# Create middle commit
+	git -C middle/bottom fetch &&
+	git -C middle/bottom checkout -f FETCH_HEAD &&
+	git -C middle add bottom &&
+	git -C middle commit -m "multiple_remote_commit" &&
+	# Create top commit
+	git -C top/middle fetch &&
+	git -C top/middle checkout -f FETCH_HEAD &&
+	git -C top add middle &&
+	git -C top commit -m "multiple_remote_commit" &&
+
+	# rename the submodule remote
+	git -C top-cloned/middle remote rename origin upstream &&
+
+	# Add another remote
+	git -C top-cloned/middle remote add other bogus &&
+
+	# Make the update of "middle" a no-op, otherwise we error out
+	# because of its unmerged state
+	test_config -C top-cloned submodule.middle.update !true &&
+	git -C top-cloned submodule update --recursive 2>actual.err &&
+	cat >expect.err <<-\EOF &&
+	EOF
+	test_cmp expect.err actual.err
+'
+
 test_expect_success 'submodule update with renamed remote' '
 	test_when_finished "rm -fr top-cloned" &&
 	cp -r top-clean top-cloned &&

-- 
2.48.1.397.gec9d649cc640

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