The 'git-refs(1)' migrate subcommand, which transfers repositories between reference backends, currently migrates reflogs by default as of 246cebe320 (refs: add support for migrating reflogs, 2024-12-16). While this behavior is desirable for most client-side repositories, server-side repositories are not expected to contain reflogs. However, due to historical reasons, some may still have them. This could be caused, for example, by bugs, misconfiguration, or an administrator enabling reflogs on the server for debugging purposes. To address this, introduce the --skip-reflog flag, allowing users to bypass reflog migration. This ensures that the repository ends up in the expected state after migration. Helped-by: Patrick Steinhardt <ps@xxxxxx> Signed-off-by: Karthik Nayak <karthik.188@xxxxxxxxx> --- Changes in v2: - Fix typo in commit mesasge and clarify the intent. - Modify the test to use `test_line_count` and `test_must_be_empty`. - Link to v1: https://lore.kernel.org/r/20250207-477-refs-migrate-add-a-flag-to-ignore-reflogs-during-migration-v1-1-7d40f3b4e30b@xxxxxxxxx --- Range-diff versus v1: 1: ce14d3d07e ! 1: 6b83089348 builtin/refs: add '--skip-reflog' flag to bypass reflog migration @@ Commit message The 'git-refs(1)' migrate subcommand, which transfers repositories between reference backends, currently migrates reflogs by default as of - In 246cebe320 (refs: add support for migrating reflogs, 2024-12-16). + 246cebe320 (refs: add support for migrating reflogs, 2024-12-16). + While this behavior is desirable for most client-side repositories, - server-side repositories typically don't use reflogs and the migration - of these entries is unnecessary overhead. + server-side repositories are not expected to contain reflogs. However, + due to historical reasons, some may still have them. This could be + caused, for example, by bugs, misconfiguration, or an administrator + enabling reflogs on the server for debugging purposes. - Add a '--skip-reflog' flag to the migrate subcommand to make reflog - migration optional. This is particularly useful for server-side - migrations where reflogs are not needed, improving migration performance - in these scenarios. + To address this, introduce the --skip-reflog flag, allowing users to + bypass reflog migration. This ensures that the repository ends up in the + expected state after migration. + Helped-by: Patrick Steinhardt <ps@xxxxxx> Signed-off-by: Karthik Nayak <karthik.188@xxxxxxxxx> ## builtin/refs.c ## @@ t/t1460-refs-migrate.sh: do + git init --ref-format=$from_format repo && + test_commit -C repo initial && + # we see that the repository contains reflogs. -+ test 2 = $(git -C repo reflog --all | wc -l) && ++ git -C repo reflog --all >reflogs && ++ test_line_count = 2 reflogs && + test_migration repo "$to_format" true --skip-reflog && + # there should be no reflogs post migration. -+ test 0 = $(git -C repo reflog --all | wc -l) ++ git -C repo reflog --all >reflogs && ++ test_must_be_empty reflogs + ' done done --- builtin/refs.c | 3 +++ refs.c | 8 +++++--- refs.h | 5 ++++- t/t1460-refs-migrate.sh | 19 +++++++++++++++++-- 4 files changed, 29 insertions(+), 6 deletions(-) diff --git a/builtin/refs.c b/builtin/refs.c index a29f19583474518ee0942ea53c39cbdf9661c5e2..30be0254c14dd3d07693d70c25dddc9990756e9c 100644 --- a/builtin/refs.c +++ b/builtin/refs.c @@ -30,6 +30,9 @@ static int cmd_refs_migrate(int argc, const char **argv, const char *prefix, OPT_BIT(0, "dry-run", &flags, N_("perform a non-destructive dry-run"), REPO_MIGRATE_REF_STORAGE_FORMAT_DRYRUN), + OPT_BIT(0, "skip-reflog", &flags, + N_("skip migrating reflogs"), + REPO_MIGRATE_REF_STORAGE_FORMAT_SKIP_REFLOG), OPT_END(), }; struct strbuf errbuf = STRBUF_INIT; diff --git a/refs.c b/refs.c index f4094a326a9f88f979654b668cc9c3d27d83cb5d..5e8f5c06fa68d16c93ee11edd9742995eea994b6 100644 --- a/refs.c +++ b/refs.c @@ -3035,9 +3035,11 @@ int repo_migrate_ref_storage_format(struct repository *repo, if (ret < 0) goto done; - ret = refs_for_each_reflog(old_refs, migrate_one_reflog, &data); - if (ret < 0) - goto done; + if (!(flags & REPO_MIGRATE_REF_STORAGE_FORMAT_SKIP_REFLOG)) { + ret = refs_for_each_reflog(old_refs, migrate_one_reflog, &data); + if (ret < 0) + goto done; + } ret = ref_transaction_commit(transaction, errbuf); if (ret < 0) diff --git a/refs.h b/refs.h index a0cdd99250e8286b55808b697b0a94afac5d8319..ccee8fc6705e6e93a1c6234e7395180f8dfd815b 100644 --- a/refs.h +++ b/refs.h @@ -1157,8 +1157,11 @@ int is_pseudo_ref(const char *refname); * - REPO_MIGRATE_REF_STORAGE_FORMAT_DRYRUN: perform a dry-run migration * without touching the main repository. The result will be written into a * temporary ref storage directory. + * + * - REPO_MIGRATE_REF_STORAGE_FORMAT_SKIP_REFLOG: skip migration of reflogs. */ -#define REPO_MIGRATE_REF_STORAGE_FORMAT_DRYRUN (1 << 0) +#define REPO_MIGRATE_REF_STORAGE_FORMAT_DRYRUN (1 << 0) +#define REPO_MIGRATE_REF_STORAGE_FORMAT_SKIP_REFLOG (1 << 1) /* * Migrate the ref storage format used by the repository to the diff --git a/t/t1460-refs-migrate.sh b/t/t1460-refs-migrate.sh index a6d9b35a46eb59350aa0d59d982a2fbfaecf1448..28c0024a4c8cb8282bf586840265edba442f5056 100755 --- a/t/t1460-refs-migrate.sh +++ b/t/t1460-refs-migrate.sh @@ -9,14 +9,16 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME # Migrate the provided repository from one format to the other and # verify that the references and logs are migrated over correctly. -# Usage: test_migration <repo> <format> <skip_reflog_verify> +# Usage: test_migration <repo> <format> <skip_reflog_verify> <...options> # <repo> is the relative path to the repo to be migrated. # <format> is the ref format to be migrated to. # <skip_reflog_verify> (true or false) whether to skip reflog verification. +# <...options> are other options be passed directly to 'git refs migrate'. test_migration () { repo=$1 && format=$2 && skip_reflog_verify=${3:-false} && + shift $(( $# >= 3 ? 3 : 2 )) && git -C "$repo" for-each-ref --include-root-refs \ --format='%(refname) %(objectname) %(symref)' >expect && if ! $skip_reflog_verify @@ -25,7 +27,7 @@ test_migration () { git -C "$repo" reflog list >expect_log_list fi && - git -C "$repo" refs migrate --ref-format="$2" && + git -C "$repo" refs migrate --ref-format="$format" $@ && git -C "$repo" for-each-ref --include-root-refs \ --format='%(refname) %(objectname) %(symref)' >actual && @@ -241,6 +243,19 @@ do test_cmp expect.reflog actual.reflog ) ' + + test_expect_success "$from_format -> $to_format: skip reflog with --skip-reflog" ' + test_when_finished "rm -rf repo" && + git init --ref-format=$from_format repo && + test_commit -C repo initial && + # we see that the repository contains reflogs. + git -C repo reflog --all >reflogs && + test_line_count = 2 reflogs && + test_migration repo "$to_format" true --skip-reflog && + # there should be no reflogs post migration. + git -C repo reflog --all >reflogs && + test_must_be_empty reflogs + ' done done --- base-commit: bc204b742735ae06f65bb20291c95985c9633b7f change-id: 20250207-477-refs-migrate-add-a-flag-to-ignore-reflogs-during-migration-8066f6df50ac Thanks - Karthik
