From: Karthik Nayak Date: Mon, 1 Dec 2025 11:24:59 +0000 (+0100) Subject: refs: add GIT_REF_URI to specify reference backend and directory X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7ccec5a1f6dfa1cd5b29054d7586768247597828;p=thirdparty%2Fgit.git refs: add GIT_REF_URI to specify reference backend and directory Git allows setting a different object directory via 'GIT_OBJECT_DIRECTORY', but provides no equivalent for references. This asymmetry makes it difficult to test different reference backends or use alternative reference storage locations without modifying the repository structure. Add a new environment variable 'GIT_REF_URI' that specifies both the reference backend and directory path using a URI format: :// When set, this variable is used to obtain the main reference store for all Git commands. The variable is checked in `get_main_ref_store()` when lazily assigning `repo->refs_private`. We cannot initialize this earlier in `repo_set_gitdir()` because the repository's hash algorithm isn't known at that point, and the reftable backend requires this information during initialization. When used with worktrees, the specified directory is treated as the reference directory for all worktree operations. Add a new test file 't1423-ref-backend.sh' to test this environment variable. Helped-by: Jean-Noël Avila Signed-off-by: Karthik Nayak Signed-off-by: Junio C Hamano --- diff --git a/Documentation/git.adoc b/Documentation/git.adoc index ce099e78b8..8c6a3f6042 100644 --- a/Documentation/git.adoc +++ b/Documentation/git.adoc @@ -584,6 +584,14 @@ double-quotes and respecting backslash escapes. E.g., the value repositories will be set to this value. The default is "files". See `--ref-format` in linkgit:git-init[1]. +`GIT_REF_URI`:: + Specify which reference backend to be used along with its URI. Reference + backends like the files, reftable backend use the $GIT_DIR as their URI. ++ +Expects the format `://`, where the +__ specifies the reference backend and the __ +specifies the URI used by the backend. + Git Commits ~~~~~~~~~~~ `GIT_AUTHOR_NAME`:: diff --git a/environment.h b/environment.h index 51898c99cd..9bc380bba4 100644 --- a/environment.h +++ b/environment.h @@ -42,6 +42,7 @@ #define GIT_OPTIONAL_LOCKS_ENVIRONMENT "GIT_OPTIONAL_LOCKS" #define GIT_TEXT_DOMAIN_DIR_ENVIRONMENT "GIT_TEXTDOMAINDIR" #define GIT_ATTR_SOURCE_ENVIRONMENT "GIT_ATTR_SOURCE" +#define GIT_REF_URI_ENVIRONMENT "GIT_REF_URI" /* * Environment variable used to propagate the --no-advice global option to the diff --git a/refs.c b/refs.c index 23f46867f2..da76e0c54a 100644 --- a/refs.c +++ b/refs.c @@ -2186,15 +2186,70 @@ static struct ref_store *get_ref_store_for_dir(struct repository *r, return maybe_debug_wrap_ref_store(dir, ref_store); } +static struct ref_store *get_ref_store_from_uri(struct repository *repo, + const char *uri) +{ + struct string_list ref_backend_info = STRING_LIST_INIT_DUP; + enum ref_storage_format format; + struct ref_store *store = NULL; + char *format_string; + char *dir; + + if (!uri) { + error(_("reference backend uri is not provided")); + goto cleanup; + } + + if (string_list_split(&ref_backend_info, uri, ":", 2) != 2) { + error(_("invalid reference backend uri format '%s'"), uri); + goto cleanup; + } + + format_string = ref_backend_info.items[0].string; + if (!starts_with(ref_backend_info.items[1].string, "//")) { + error(_("invalid reference backend uri format '%s'"), uri); + goto cleanup; + } + dir = ref_backend_info.items[1].string + 2; + + if (!dir[0]) { + error(_("invalid path in uri '%s'"), uri); + goto cleanup; + } + + format = ref_storage_format_by_name(format_string); + if (format == REF_STORAGE_FORMAT_UNKNOWN) { + error(_("unknown reference backend '%s'"), format_string); + goto cleanup; + } + + store = get_ref_store_for_dir(repo, dir, format); + +cleanup: + string_list_clear(&ref_backend_info, 0); + return store; +} + struct ref_store *get_main_ref_store(struct repository *r) { + char *ref_uri; + if (r->refs_private) return r->refs_private; if (!r->gitdir) BUG("attempting to get main_ref_store outside of repository"); - r->refs_private = get_ref_store_for_dir(r, r->gitdir, r->ref_storage_format); + ref_uri = getenv(GIT_REF_URI_ENVIRONMENT); + if (ref_uri) { + r->refs_private = get_ref_store_from_uri(r, ref_uri); + if (!r->refs_private) + die("failed to initialize ref store from URI: %s", ref_uri); + + } else { + r->refs_private = get_ref_store_for_dir(r, r->gitdir, + r->ref_storage_format); + } return r->refs_private; } diff --git a/t/meson.build b/t/meson.build index a5531df415..a66f8fafff 100644 --- a/t/meson.build +++ b/t/meson.build @@ -208,6 +208,7 @@ integration_tests = [ 't1420-lost-found.sh', 't1421-reflog-write.sh', 't1422-show-ref-exists.sh', + 't1423-ref-backend.sh', 't1430-bad-ref-name.sh', 't1450-fsck.sh', 't1451-fsck-buffer.sh', diff --git a/t/t1423-ref-backend.sh b/t/t1423-ref-backend.sh new file mode 100755 index 0000000000..f36125bf64 --- /dev/null +++ b/t/t1423-ref-backend.sh @@ -0,0 +1,121 @@ +#!/bin/sh + +test_description='Test different reference backend URIs' + +. ./test-lib.sh + +test_expect_success 'empty uri provided' ' + test_when_finished "rm -rf repo" && + git init --ref-format=files repo && + ( + cd repo && + GIT_REF_URI="" && + export GIT_REF_URI && + test_must_fail git refs list 2>err && + test_grep "invalid reference backend uri format" err + ) +' + +test_expect_success 'invalid uri provided' ' + test_when_finished "rm -rf repo" && + git init --ref-format=files repo && + ( + cd repo && + GIT_REF_URI="reftable@/home/reftable" && + export GIT_REF_URI && + test_must_fail git refs list 2>err && + test_grep "invalid reference backend uri format" err + ) +' + +test_expect_success 'empty path in uri' ' + test_when_finished "rm -rf repo" && + git init --ref-format=files repo && + ( + cd repo && + GIT_REF_URI="reftable://" && + export GIT_REF_URI && + test_must_fail git refs list 2>err && + test_grep "invalid path in uri" err + ) +' + +test_expect_success 'uri ends at colon' ' + test_when_finished "rm -rf repo" && + git init --ref-format=files repo && + ( + cd repo && + GIT_REF_URI="reftable:" && + export GIT_REF_URI && + test_must_fail git refs list 2>err && + test_grep "invalid reference backend uri format" err + ) +' + +test_expect_success 'unknown reference backend' ' + test_when_finished "rm -rf repo" && + git init --ref-format=files repo && + ( + cd repo && + GIT_REF_URI="db://.git" && + export GIT_REF_URI && + test_must_fail git refs list 2>err && + test_grep "unknown reference backend" err + ) +' + +ref_formats="files reftable" +for from_format in $ref_formats +do + for to_format in $ref_formats + do + if test "$from_format" = "$to_format" + then + continue + fi + + test_expect_success "read from $to_format backend" ' + test_when_finished "rm -rf repo" && + git init --ref-format=$from_format repo && + ( + cd repo && + test_commit 1 && + test_commit 2 && + test_commit 3 && + + git refs migrate --dry-run --ref-format=$to_format >out && + BACKEND_PATH=$(cat out | sed "s/.* ${SQ}\(.*\)${SQ}/\1/") && + git refs list >expect && + GIT_REF_URI="$to_format://$BACKEND_PATH" git refs list >actual && + test_cmp expect actual + ) + ' + + test_expect_success "write to $to_format backend" ' + test_when_finished "rm -rf repo" && + git init --ref-format=$from_format repo && + ( + cd repo && + test_commit 1 && + test_commit 2 && + test_commit 3 && + + git refs migrate --dry-run --ref-format=$to_format >out && + git refs list >expect && + + BACKEND_PATH=$(cat out | sed "s/.* ${SQ}\(.*\)${SQ}/\1/") && + GIT_REF_URI="$to_format://$BACKEND_PATH" git tag -d 1 && + + git refs list >actual && + test_cmp expect actual && + + GIT_REF_URI="$to_format://$BACKEND_PATH" git refs list >expect && + git refs list >out && + cat out | grep -v "refs/tags/1" >actual && + test_cmp expect actual + ) + ' + done +done + +test_done