Merge branch 'dt/disable-bitmap-in-auto-gc' into maint

It is natural that "git gc --auto" may not attempt to pack
everything into a single pack, and there is no point in warning
when the user has configured the system to use the pack bitmap,
leading to disabling further "gc".

* dt/disable-bitmap-in-auto-gc:
  repack: die on incremental + write-bitmap-index
  auto gc: don't write bitmaps for incremental repacks

builtin/gc.c

@@ -191,6 +191,11 @@ static void add_repack_all_option(void)
 	}
 }
 
+static void add_repack_incremental_option(void)
+{
+       argv_array_push(&repack, "--no-write-bitmap-index");
+}
+
 static int need_to_gc(void)
 {
 	/*
@@ -208,7 +213,9 @@ static int need_to_gc(void)
 	 */
 	if (too_many_packs())
 		add_repack_all_option();
-	else if (!too_many_loose_objects())
+	else if (too_many_loose_objects())
+		add_repack_incremental_option();
+	else
 		return 0;
 
 	if (run_hook_le(NULL, "pre-auto-gc", NULL))

builtin/repack.c

@@ -18,6 +18,12 @@ static const char *const git_repack_usage[] = {
 	NULL
 };
 
+static const char incremental_bitmap_conflict_error[] = N_(
+"Incremental repacks are incompatible with bitmap indexes.  Use\n"
+"--no-write-bitmap-index or disable the pack.writebitmaps configuration."
+);
+
+
 static int repack_config(const char *var, const char *value, void *cb)
 {
 	if (!strcmp(var, "repack.usedeltabaseoffset")) {
@@ -206,6 +212,9 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 	if (pack_kept_objects < 0)
 		pack_kept_objects = write_bitmaps;
 
+	if (write_bitmaps && !(pack_everything & ALL_INTO_ONE))
+		die(_(incremental_bitmap_conflict_error));
+
 	packdir = mkpathdup("%s/pack", get_object_directory());
 	packtmp = mkpathdup("%s/.tmp-%d-pack", packdir, (int)getpid());
 

t/t5310-pack-bitmaps.sh

@@ -118,12 +118,10 @@ test_expect_success 'fetch (partial bitmap)' '
 	test_cmp expect actual
 '
 
-test_expect_success 'incremental repack cannot create bitmaps' '
+test_expect_success 'incremental repack fails when bitmaps are requested' '
 	test_commit more-1 &&
-	find .git/objects/pack -name "*.bitmap" >expect &&
+	test_must_fail git repack -d 2>err &&
-	git repack -d &&
+	test_i18ngrep "Incremental repacks are incompatible with bitmap" err
-	find .git/objects/pack -name "*.bitmap" >actual &&
-	test_cmp expect actual
 '
 
 test_expect_success 'incremental repack can disable bitmaps' '

t/t6500-gc.sh

@@ -43,4 +43,29 @@ test_expect_success 'gc is not aborted due to a stale symref' '
 	)
 '
 
+test_expect_success 'auto gc with too many loose objects does not attempt to create bitmaps' '
+	test_config gc.auto 3 &&
+	test_config gc.autodetach false &&
+	test_config pack.writebitmaps true &&
+	# We need to create two object whose sha1s start with 17
+	# since this is what git gc counts.  As it happens, these
+	# two blobs will do so.
+	test_commit 263 &&
+	test_commit 410 &&
+	# Our first gc will create a pack; our second will create a second pack
+	git gc --auto &&
+	ls .git/objects/pack | sort >existing_packs &&
+	test_commit 523 &&
+	test_commit 790 &&
+
+	git gc --auto 2>err &&
+	test_i18ngrep ! "^warning:" err &&
+	ls .git/objects/pack/ | sort >post_packs &&
+	comm -1 -3 existing_packs post_packs >new &&
+	comm -2 -3 existing_packs post_packs >del &&
+	test_line_count = 0 del && # No packs are deleted
+	test_line_count = 2 new # There is one new pack and its .idx
+'
+
+
 test_done