From: Adrian Ratiu Date: Sat, 20 Dec 2025 10:15:26 +0000 (+0200) Subject: submodule: fix case-folding gitdir filesystem collisions X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c69414808cc0dd39ca9aa379cb00d5317aa5a7e7;p=thirdparty%2Fgit.git submodule: fix case-folding gitdir filesystem collisions Add a new check when extension.submodulePathConfig is enabled, to detect and prevent case-folding filesystem colisions. When this new check is triggered, a stricter casefolding aware URI encoding is used to percent-encode uppercase characters. By using this check/retry mechanism the uppercase encoding is only applied when necessary, so case-sensitive filesystems are not affected. Signed-off-by: Adrian Ratiu Signed-off-by: Junio C Hamano --- diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c index f19672f01a..f9fc4c6eb5 100644 --- a/builtin/submodule--helper.c +++ b/builtin/submodule--helper.c @@ -473,7 +473,7 @@ static void create_default_gitdir_config(const char *submodule_name) return; } - /* Case 2: Try URI-safe (RFC3986) encoding first, this fixes nested gitdirs */ + /* Case 2.1: Try URI-safe (RFC3986) encoding first, this fixes nested gitdirs */ strbuf_reset(&gitdir_path); repo_git_path_append(the_repository, &gitdir_path, "modules/"); strbuf_addstr_urlencode(&gitdir_path, submodule_name, is_rfc3986_unreserved); @@ -482,6 +482,30 @@ static void create_default_gitdir_config(const char *submodule_name) return; } + /* Case 2.2: Try extended uppercase URI (RFC3986) encoding, to fix case-folding */ + strbuf_reset(&gitdir_path); + repo_git_path_append(the_repository, &gitdir_path, "modules/"); + strbuf_addstr_urlencode(&gitdir_path, submodule_name, is_casefolding_rfc3986_unreserved); + if (!validate_and_set_submodule_gitdir(&gitdir_path, submodule_name)) + return; + + /* Case 2.3: Try some derived gitdir names, see if one sticks */ + for (char c = '0'; c <= '9'; c++) { + strbuf_reset(&gitdir_path); + repo_git_path_append(the_repository, &gitdir_path, "modules/"); + strbuf_addstr_urlencode(&gitdir_path, submodule_name, is_rfc3986_unreserved); + strbuf_addch(&gitdir_path, c); + if (!validate_and_set_submodule_gitdir(&gitdir_path, submodule_name)) + return; + + strbuf_reset(&gitdir_path); + repo_git_path_append(the_repository, &gitdir_path, "modules/"); + strbuf_addstr_urlencode(&gitdir_path, submodule_name, is_casefolding_rfc3986_unreserved); + strbuf_addch(&gitdir_path, c); + if (!validate_and_set_submodule_gitdir(&gitdir_path, submodule_name)) + return; + } + /* Case 3: nothing worked, error out */ die(_("failed to set a valid default config for 'submodule.%s.gitdir'. " "Please ensure it is set, for example by running something like: " diff --git a/submodule.c b/submodule.c index 0dc1fedcae..8b7f6ed4e5 100644 --- a/submodule.c +++ b/submodule.c @@ -2253,15 +2253,58 @@ out: return ret; } +static int check_casefolding_conflict(const char *git_dir, + const char *submodule_name, + const bool suffixes_match) +{ + char *p, *modules_dir = xstrdup(git_dir); + struct dirent *de; + DIR *dir = NULL; + int ret = 0; + + if ((p = find_last_dir_sep(modules_dir))) + *p = '\0'; + + /* No conflict is possible if modules_dir doesn't exist (first clone) */ + if (!is_directory(modules_dir)) + goto cleanup; + + dir = opendir(modules_dir); + if (!dir) { + ret = -1; + goto cleanup; + } + + /* Check for another directory under .git/modules that differs only in case. */ + while ((de = readdir(dir))) { + if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) + continue; + + if ((suffixes_match || is_git_directory(git_dir)) && + !strcasecmp(de->d_name, submodule_name) && + strcmp(de->d_name, submodule_name)) { + ret = -1; /* collision found */ + break; + } + } + +cleanup: + if (dir) + closedir(dir); + free(modules_dir); + return ret; +} + /* * Encoded gitdir validation, only used when extensions.submodulePathConfig is enabled. * This does not print errors like the non-encoded version, because encoding is supposed * to mitigate / fix all these. */ -static int validate_submodule_encoded_git_dir(char *git_dir, const char *submodule_name UNUSED) +static int validate_submodule_encoded_git_dir(char *git_dir, const char *submodule_name) { const char *modules_marker = "/modules/"; char *p = git_dir, *last_submodule_name = NULL; + int config_ignorecase = 0; if (!the_repository->repository_format_submodule_path_cfg) BUG("validate_submodule_encoded_git_dir() must be called with " @@ -2277,6 +2320,14 @@ 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 on case-folding filesystems */ + repo_config_get_bool(the_repository, "core.ignorecase", &config_ignorecase); + if (ignore_case || config_ignorecase) { + bool suffixes_match = !strcmp(last_submodule_name, submodule_name); + return check_casefolding_conflict(git_dir, submodule_name, + suffixes_match); + } + return 0; } diff --git a/t/t7425-submodule-gitdir-path-extension.sh b/t/t7425-submodule-gitdir-path-extension.sh index dbe18f2925..eb9c80787c 100755 --- a/t/t7425-submodule-gitdir-path-extension.sh +++ b/t/t7425-submodule-gitdir-path-extension.sh @@ -384,4 +384,39 @@ test_expect_success 'disabling extensions.submodulePathConfig prevents nested su ) ' +test_expect_success CASE_INSENSITIVE_FS 'verify case-folding conflicts are correctly encoded' ' + git clone -c extensions.submodulePathConfig=true main cloned-folding && + ( + cd cloned-folding && + + # conflict: the "folding" gitdir will already be taken + git submodule add ../new-sub "folding" && + test_commit lowercase && + git submodule add ../new-sub "FoldinG" && + test_commit uppercase && + + # conflict: the "foo" gitdir will already be taken + git submodule add ../new-sub "FOO" && + test_commit uppercase-foo && + git submodule add ../new-sub "foo" && + test_commit lowercase-foo && + + # create a multi conflict between foobar, fooBar and foo%42ar + # the "foo" gitdir will already be taken + git submodule add ../new-sub "foobar" && + test_commit lowercase-foobar && + git submodule add ../new-sub "foo%42ar" && + test_commit encoded-foo%42ar && + git submodule add ../new-sub "fooBar" && + test_commit mixed-fooBar + ) && + verify_submodule_gitdir_path cloned-folding "folding" "modules/folding" && + verify_submodule_gitdir_path cloned-folding "FoldinG" "modules/%46oldin%47" && + verify_submodule_gitdir_path cloned-folding "FOO" "modules/FOO" && + verify_submodule_gitdir_path cloned-folding "foo" "modules/foo0" && + verify_submodule_gitdir_path cloned-folding "foobar" "modules/foobar" && + verify_submodule_gitdir_path cloned-folding "foo%42ar" "modules/foo%42ar" && + verify_submodule_gitdir_path cloned-folding "fooBar" "modules/fooBar0" +' + test_done diff --git a/url.c b/url.c index adc289229c..3ca5987e90 100644 --- a/url.c +++ b/url.c @@ -9,6 +9,13 @@ int is_rfc3986_unreserved(char ch) ch == '-' || ch == '_' || ch == '.' || ch == '~'; } +int is_casefolding_rfc3986_unreserved(char c) +{ + return (c >= 'a' && c <= 'z') || + (c >= '0' && c <= '9') || + c == '-' || c == '.' || c == '_' || c == '~'; +} + int is_urlschemechar(int first_flag, int ch) { /* diff --git a/url.h b/url.h index e644c3c809..cd9140e994 100644 --- a/url.h +++ b/url.h @@ -28,4 +28,11 @@ void str_end_url_with_slash(const char *url, char **dest); */ int is_rfc3986_unreserved(char ch); +/* + * This is a variant of is_rfc3986_unreserved() that treats uppercase + * letters as "reserved". This forces them to be percent-encoded, allowing + * 'Foo' (%46oo) and 'foo' (foo) to be distinct on case-folding filesystems. + */ +int is_casefolding_rfc3986_unreserved(char c); + #endif /* URL_H */