@matheusbsbs / matheus-bagliano / commits / e897c9b7f3

submodule: detect conflicts with existing gitdir configs

Credit goes to Emily and Josh for testing and noticing a corner-case which caused conflicts with existing gitdir configs to silently pass validation, then fail later in add_submodule() with a cryptic error: fatal: A git directory for 'nested%2fsub' is found locally with remote(s): origin /.../trash directory.t7425-submodule-gitdir-path-extension/sub This change ensures the validation step checks existing gitdirs for conflicts. We only have to do this for submodules having gitdirs, because those without submodule.%s.gitdir need to be migrated and will throw an error earlier in the submodule codepath. Quoting Josh: My testing setup has been as follows: * Using our locally-built Git with our downstream patch of [1] included: * create a repo "sub" * create a repo "super" * In "super": * mkdir nested * git submodule add ../sub nested/sub * Verify that the submodule's gitdir is .git/modules/nested%2fsub * Using a build of git from upstream `next` plus this series: * git config set --global extensions.submodulepathconfig true * git clone --recurse-submodules super super2 * create a repo "nested%2fsub" * In "super2": * git submodule add ../nested%2fsub At this point I'd expect the collision detection / encoding to take effect, but instead I get the error listed above. End quote Suggested-by: Josh Steadmon <steadmon@google.com> Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Adrian Ratiu committed Jan 12, 2026 at 20:46 UTC e897c9b7f31cf83e93cfefe1f82eb4a18337c9b1
2 files changed +89
submodule.c
+61
index a5a47359c7..4ab3fcb598 100644 --- a/submodule.c +++ b/submodule.c @@ -2296,6 +2296,62 @@ cleanup: return ret; } +struct submodule_from_gitdir_cb { + const char *gitdir; + const char *submodule_name; + bool conflict_found; +}; + +static int find_conflict_by_gitdir_cb(const char *var, const char *value, + const struct config_context *ctx UNUSED, void *data) +{ + struct submodule_from_gitdir_cb *cb = data; + const char *submodule_name_start; + size_t submodule_name_len; + const char *suffix = ".gitdir"; + size_t suffix_len = strlen(suffix); + + if (!skip_prefix(var, "submodule.", &submodule_name_start)) + return 0; + + /* Check if submodule_name_start ends with ".gitdir" */ + submodule_name_len = strlen(submodule_name_start); + if (submodule_name_len < suffix_len || + strcmp(submodule_name_start + submodule_name_len - suffix_len, suffix) != 0) + return 0; /* Does not end with ".gitdir" */ + + submodule_name_len -= suffix_len; + + /* + * A conflict happens if: + * 1. The submodule names are different and + * 2. The gitdir paths resolve to the same absolute path + */ + if (value && strncmp(cb->submodule_name, submodule_name_start, submodule_name_len)) { + char *abs_path_cb = absolute_pathdup(cb->gitdir); + char *abs_path_value = absolute_pathdup(value); + + cb->conflict_found = !strcmp(abs_path_cb, abs_path_value); + + free(abs_path_cb); + free(abs_path_value); + } + + return cb->conflict_found; +} + +static bool submodule_conflicts_with_existing(const char *gitdir, const char *submodule_name) +{ + struct submodule_from_gitdir_cb cb = { 0 }; + cb.submodule_name = submodule_name; + cb.gitdir = gitdir; + + /* Find conflicts with existing repo gitdir configs */ + repo_config(the_repository, find_conflict_by_gitdir_cb, &cb); + + return cb.conflict_found; +} + /* * Encoded gitdir validation, only used when extensions.submodulePathConfig is enabled. * This does not print errors like the non-encoded version, because encoding is supposed @@ -2321,6 +2377,11 @@ static int validate_submodule_encoded_git_dir(char *git_dir, const char *submodu if (!last_submodule_name || strchr(last_submodule_name, '/')) return -1; + /* Prevent conflicts with existing submodule gitdirs */ + if (is_git_directory(git_dir) && + submodule_conflicts_with_existing(git_dir, submodule_name)) + return -1; + /* Prevent conflicts on case-folding filesystems */ repo_config_get_bool(the_repository, "core.ignorecase", &config_ignorecase); if (ignore_case || config_ignorecase) {
t/t7425-submodule-gitdir-path-extension.sh
+28
index a76e64a9f7..ea86ecf7ee 100755 --- a/t/t7425-submodule-gitdir-path-extension.sh +++ b/t/t7425-submodule-gitdir-path-extension.sh @@ -497,4 +497,32 @@ test_expect_success CASE_INSENSITIVE_FS 'verify hashing conflict resolution as a verify_submodule_gitdir_path cloned-hash "Foo" "modules/${hash}" ' +test_expect_success 'submodule gitdir conflicts with previously encoded name (local config)' ' + git init -b main super_with_encoded && + ( + cd super_with_encoded && + + git config core.repositoryformatversion 1 && + git config extensions.submodulePathConfig true && + + # Add a submodule with a nested path + git submodule add --name "nested/sub" ../sub nested/sub && + test_commit add-encoded-gitdir && + + verify_submodule_gitdir_path . "nested/sub" "modules/nested%2fsub" && + test_path_is_dir ".git/modules/nested%2fsub" + ) && + + # create a submodule that will conflict with the encoded gitdir name: + # the existing gitdir is ".git/modules/nested%2fsub", which is used + # by "nested/sub", so the new submod will get another (non-conflicting) + # name: "nested%252fsub". + ( + cd super_with_encoded && + git submodule add ../sub "nested%2fsub" && + verify_submodule_gitdir_path . "nested%2fsub" "modules/nested%252fsub" && + test_path_is_dir ".git/modules/nested%252fsub" + ) +' + test_done