builtin/gc.c: conditionally avoid pruning objects via loose

Expose the new `git repack --cruft` mode from `git gc` via a new opt-in
flag. When invoked like `git gc --cruft`, `git gc` will avoid exploding
unreachable objects as loose ones, and instead create a cruft pack and
`.mtimes` file.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config/gc.txt b/Documentation/config/gc.txt
index c834e07991fec00d976cc105760814694deb8f68..38fea076a26d0f1f7bf137723baba945675901fc 100644 (file)
--- a/Documentation/config/gc.txt
+++ b/Documentation/config/gc.txt
@@ -81,14 +81,21 @@ gc.packRefs::
        to enable it within all non-bare repos or it can be set to a
        boolean value.  The default is `true`.
 
+gc.cruftPacks::
+       Store unreachable objects in a cruft pack (see
+       linkgit:git-repack[1]) instead of as loose objects. The default
+       is `false`.
+
 gc.pruneExpire::
-       When 'git gc' is run, it will call 'prune --expire 2.weeks.ago'.
-       Override the grace period with this config variable.  The value
-       "now" may be used to disable this grace period and always prune
-       unreachable objects immediately, or "never" may be used to
-       suppress pruning.  This feature helps prevent corruption when
-       'git gc' runs concurrently with another process writing to the
-       repository; see the "NOTES" section of linkgit:git-gc[1].
+       When 'git gc' is run, it will call 'prune --expire 2.weeks.ago'
+       (and 'repack --cruft --cruft-expiration 2.weeks.ago' if using
+       cruft packs via `gc.cruftPacks` or `--cruft`).  Override the
+       grace period with this config variable.  The value "now" may be
+       used to disable this grace period and always prune unreachable
+       objects immediately, or "never" may be used to suppress pruning.
+       This feature helps prevent corruption when 'git gc' runs
+       concurrently with another process writing to the repository; see
+       the "NOTES" section of linkgit:git-gc[1].
 
 gc.worktreePruneExpire::
        When 'git gc' is run, it calls

diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt
index 853967dea01d0778e8d1d484afa9098ab4532ffc..ba4e67700ec2988de87074914a428737937dbfc3 100644 (file)
--- a/Documentation/git-gc.txt
+++ b/Documentation/git-gc.txt
@@ -54,6 +54,11 @@ other housekeeping tasks (e.g. rerere, working trees, reflog...) will
 be performed as well.
 
 
+--cruft::
+       When expiring unreachable objects, pack them separately into a
+       cruft pack instead of storing the loose objects as loose
+       objects.
+
 --prune=<date>::
        Prune loose objects older than date (default is 2 weeks ago,
        overridable by the config variable `gc.pruneExpire`).

diff --git a/builtin/gc.c b/builtin/gc.c
index b335cffa33561fa80f268260a7edbc7af9ae4136..4d995e85e90cc26b9749c9aa14907b1538232414 100644 (file)
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -42,6 +42,7 @@ static const char * const builtin_gc_usage[] = {
 
 static int pack_refs = 1;
 static int prune_reflogs = 1;
+static int cruft_packs = 0;
 static int aggressive_depth = 50;
 static int aggressive_window = 250;
 static int gc_auto_threshold = 6700;
@@ -152,6 +153,7 @@ static void gc_config(void)
        git_config_get_int("gc.auto", &gc_auto_threshold);
        git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
        git_config_get_bool("gc.autodetach", &detach_auto);
+       git_config_get_bool("gc.cruftpacks", &cruft_packs);
        git_config_get_expiry("gc.pruneexpire", &prune_expire);
        git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
        git_config_get_expiry("gc.logexpiry", &gc_log_expire);
@@ -331,7 +333,11 @@ static void add_repack_all_option(struct string_list *keep_pack)
 {
        if (prune_expire && !strcmp(prune_expire, "now"))
                strvec_push(&repack, "-a");
-       else {
+       else if (cruft_packs) {
+               strvec_push(&repack, "--cruft");
+               if (prune_expire)
+                       strvec_pushf(&repack, "--cruft-expiration=%s", prune_expire);
+       } else {
                strvec_push(&repack, "-A");
                if (prune_expire)
                        strvec_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
@@ -551,6 +557,7 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
                        N_("prune unreferenced objects"),
                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
+               OPT_BOOL(0, "cruft", &cruft_packs, N_("pack unreferenced objects separately")),
                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
                OPT_BOOL_F(0, "auto", &auto_gc, N_("enable auto-gc mode"),
                           PARSE_OPT_NOCOMPLETE),
@@ -670,6 +677,7 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
                        die(FAILED_RUN, repack.v[0]);
 
                if (prune_expire) {
+                       /* run `git prune` even if using cruft packs */
                        strvec_push(&prune, prune_expire);
                        if (quiet)
                                strvec_push(&prune, "--no-progress");

diff --git a/t/t5329-pack-objects-cruft.sh b/t/t5329-pack-objects-cruft.sh
index 8de87afce21a654026622ff93d2c9f4f735c3450..70a6a9553c71ce901d6d772b51ff9562f47bce1a 100755 (executable)
--- a/t/t5329-pack-objects-cruft.sh
+++ b/t/t5329-pack-objects-cruft.sh
@@ -429,6 +429,43 @@ test_expect_success 'loose objects mtimes upsert others' '
        )
 '
 
+test_expect_success 'expiring cruft objects with git gc' '
+       git init repo &&
+       test_when_finished "rm -fr repo" &&
+       (
+               cd repo &&
+
+               test_commit reachable &&
+               git branch -M main &&
+               git checkout --orphan other &&
+               test_commit unreachable &&
+
+               git checkout main &&
+               git branch -D other &&
+               git tag -d unreachable &&
+               # objects are not cruft if they are contained in the reflogs
+               git reflog expire --all --expire=all &&
+
+               git rev-list --objects --all --no-object-names >reachable.raw &&
+               git cat-file --batch-all-objects --batch-check="%(objectname)" >objects &&
+               sort <reachable.raw >reachable &&
+               comm -13 reachable objects >unreachable &&
+
+               git repack --cruft -d &&
+
+               mtimes=$(ls .git/objects/pack/pack-*.mtimes) &&
+               test_path_is_file $mtimes &&
+
+               git gc --cruft --prune=now &&
+
+               git cat-file --batch-all-objects --batch-check="%(objectname)" >objects &&
+
+               comm -23 unreachable objects >removed &&
+               test_cmp unreachable removed &&
+               test_path_is_missing $mtimes
+       )
+'
+
 test_expect_success 'cruft packs are not included in geometric repack' '
        git init repo &&
        test_when_finished "rm -fr repo" &&