gc: call "prune --expire 2.weeks.ago" by default

The only reason we did not call "prune" in git-gc was that it is an
inherently dangerous operation: if there is a commit going on, you will
prune loose objects that were just created, and are, in fact, needed by the
commit object just about to be created.

Since it is dangerous, we told users so.  That led to many users not even
daring to run it when it was actually safe. Besides, they are users, and
should not have to remember such details as when to call git-gc with
--prune, or to call git-prune directly.

Of course, the consequence was that "git gc --auto" gets triggered much
more often than we would like, since unreferenced loose objects (such as
left-overs from a rebase or a reset --hard) were never pruned.

Alas, git-prune recently learnt the option --expire <minimum-age>, which
makes it a much safer operation.  This allows us to call prune from git-gc,
with a grace period of 2 weeks for the unreferenced loose objects (this
value was determined in a discussion on the git list as a safe one).

If you want to override this grace period, just set the config variable
gc.pruneExpire to a different value; an example would be

	[gc]
		pruneExpire = 6.months.ago

or even "never", if you feel really paranoid.

Note that this new behaviour makes "--prune" be a no-op.

While adding a test to t5304-prune.sh (since it really tests the implicit
call to "prune"), also the original test for "prune --expire" was moved
there from t1410-reflog.sh, where it did not belong.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 35824258cabece3f5e1d5d6e1793ec4201612166..bfad0e3858047aa4606e48120e16831e6f17c2f7 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -590,6 +590,10 @@ gc.packrefs::
        at some stage, and setting this to `false` will continue to
        prevent `git pack-refs` from being run from `git gc`.
 
+gc.pruneexpire::
+       When `git gc` is run, it will call `prune --expire 2.weeks.ago`.
+       Override the grace period with this config variable.
+
 gc.reflogexpire::
        `git reflog expire` removes reflog entries older than
        this time; defaults to 90 days.

diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt
index 2e7be916aa5dede578b181e06457189551c16240..229a7c9b30482eb2d8729b581004bc776fa10edf 100644 (file)
--- a/Documentation/git-gc.txt
+++ b/Documentation/git-gc.txt
@@ -8,7 +8,7 @@ git-gc - Cleanup unnecessary files and optimize the local repository
 
 SYNOPSIS
 --------
-'git-gc' [--prune] [--aggressive] [--auto] [--quiet]
+'git-gc' [--aggressive] [--auto] [--quiet]
 
 DESCRIPTION
 -----------
@@ -25,17 +25,6 @@ operating performance. Some git commands may automatically run
 OPTIONS
 -------
 
---prune::
-       Usually `git-gc` packs refs, expires old reflog entries,
-       packs loose objects,
-       and removes old 'rerere' records.  Removal
-       of unreferenced loose objects is an unsafe operation
-       while other git operations are in progress, so it is not
-       done by default.  Pass this option if you want it, and only
-       when you know nobody else is creating new objects in the
-       repository at the same time (e.g. never use this option
-       in a cron script).
-
 --aggressive::
        Usually 'git-gc' runs very quickly while providing good disk
        space utilization and performance.  This option will cause
@@ -104,6 +93,10 @@ the value, the more time is spent optimizing the delta compression.  See
 the documentation for the --window' option in linkgit:git-repack[1] for
 more details.  This defaults to 10.
 
+The optional configuration variable 'gc.pruneExpire' controls how old
+the unreferenced loose objects have to be before they are pruned.  The
+default is "2 weeks ago".
+
 See Also
 --------
 linkgit:git-prune[1]

diff --git a/builtin-gc.c b/builtin-gc.c
index 045bf0e487a73e98d8d78990fcf85cc25ad5f96d..95917d74a873065bf9f928da37aa40e9e0d1f688 100644 (file)
--- a/builtin-gc.c
+++ b/builtin-gc.c
@@ -26,12 +26,13 @@ static int pack_refs = 1;
 static int aggressive_window = -1;
 static int gc_auto_threshold = 6700;
 static int gc_auto_pack_limit = 20;
+static char *prune_expire = "2.weeks.ago";
 
 #define MAX_ADD 10
 static const char *argv_pack_refs[] = {"pack-refs", "--all", "--prune", NULL};
 static const char *argv_reflog[] = {"reflog", "expire", "--all", NULL};
 static const char *argv_repack[MAX_ADD] = {"repack", "-d", "-l", NULL};
-static const char *argv_prune[] = {"prune", NULL};
+static const char *argv_prune[] = {"prune", "--expire", NULL, NULL};
 static const char *argv_rerere[] = {"rerere", "gc", NULL};
 
 static int gc_config(const char *var, const char *value)
@@ -55,6 +56,17 @@ static int gc_config(const char *var, const char *value)
                gc_auto_pack_limit = git_config_int(var, value);
                return 0;
        }
+       if (!strcmp(var, "gc.pruneexpire")) {
+               if (!value)
+                       return config_error_nonbool(var);
+               if (strcmp(value, "now")) {
+                       unsigned long now = approxidate("now");
+                       if (approxidate(value) >= now)
+                               return error("Invalid %s: '%s'", var, value);
+               }
+               prune_expire = xstrdup(value);
+               return 0;
+       }
        return git_default_config(var, value);
 }
 
@@ -234,7 +246,8 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
        if (run_command_v_opt(argv_repack, RUN_GIT_CMD))
                return error(FAILED_RUN, argv_repack[0]);
 
-       if (prune && run_command_v_opt(argv_prune, RUN_GIT_CMD))
+       argv_prune[2] = prune_expire;
+       if (run_command_v_opt(argv_prune, RUN_GIT_CMD))
                return error(FAILED_RUN, argv_prune[0]);
 
        if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))

diff --git a/t/t1410-reflog.sh b/t/t1410-reflog.sh
index 24476bede5ce8f8720bf3d9eba7f7a944182dbf4..73f830db2374e751fb46e25b345e860979b9dd05 100755 (executable)
--- a/t/t1410-reflog.sh
+++ b/t/t1410-reflog.sh
@@ -202,22 +202,4 @@ test_expect_success 'delete' '
 
 '
 
-test_expect_success 'prune --expire' '
-
-       before=$(git count-objects | sed "s/ .*//") &&
-       BLOB=$(echo aleph | git hash-object -w --stdin) &&
-       BLOB_FILE=.git/objects/$(echo $BLOB | sed "s/^../&\//") &&
-       test $((1 + $before)) = $(git count-objects | sed "s/ .*//") &&
-       test -f $BLOB_FILE &&
-       git reset --hard &&
-       git prune --expire=1.hour.ago &&
-       test $((1 + $before)) = $(git count-objects | sed "s/ .*//") &&
-       test -f $BLOB_FILE &&
-       test-chmtime -86500 $BLOB_FILE &&
-       git prune --expire 1.day &&
-       test $before = $(git count-objects | sed "s/ .*//") &&
-       ! test -f $BLOB_FILE
-
-'
-
 test_done

diff --git a/t/t5304-prune.sh b/t/t5304-prune.sh
index 6560af756e7b4df0c7777e818edc86854f74b973..47090c4cf528016bf864116232baf29aeb1e4bfe 100644 (file)
--- a/t/t5304-prune.sh
+++ b/t/t5304-prune.sh
@@ -29,4 +29,53 @@ test_expect_success 'prune stale packs' '
 
 '
 
+test_expect_success 'prune --expire' '
+
+       before=$(git count-objects | sed "s/ .*//") &&
+       BLOB=$(echo aleph | git hash-object -w --stdin) &&
+       BLOB_FILE=.git/objects/$(echo $BLOB | sed "s/^../&\//") &&
+       test $((1 + $before)) = $(git count-objects | sed "s/ .*//") &&
+       test -f $BLOB_FILE &&
+       git prune --expire=1.hour.ago &&
+       test $((1 + $before)) = $(git count-objects | sed "s/ .*//") &&
+       test -f $BLOB_FILE &&
+       test-chmtime -86500 $BLOB_FILE &&
+       git prune --expire 1.day &&
+       test $before = $(git count-objects | sed "s/ .*//") &&
+       ! test -f $BLOB_FILE
+
+'
+
+test_expect_success 'gc: implicit prune --expire' '
+
+       before=$(git count-objects | sed "s/ .*//") &&
+       BLOB=$(echo aleph_0 | git hash-object -w --stdin) &&
+       BLOB_FILE=.git/objects/$(echo $BLOB | sed "s/^../&\//") &&
+       test $((1 + $before)) = $(git count-objects | sed "s/ .*//") &&
+       test -f $BLOB_FILE &&
+       test-chmtime -$((86400*14-30)) $BLOB_FILE &&
+       git gc &&
+       test $((1 + $before)) = $(git count-objects | sed "s/ .*//") &&
+       test -f $BLOB_FILE &&
+       test-chmtime -$((86400*14+1)) $BLOB_FILE &&
+       git gc &&
+       test $before = $(git count-objects | sed "s/ .*//") &&
+       ! test -f $BLOB_FILE
+
+'
+
+test_expect_success 'gc: refuse to start with invalid gc.pruneExpire' '
+
+       git config gc.pruneExpire invalid &&
+       test_must_fail git gc
+
+'
+
+test_expect_success 'gc: start with ok gc.pruneExpire' '
+
+       git config gc.pruneExpire 2.days.ago &&
+       git gc
+
+'
+
 test_done