Merge branch 'ab/gc-reflog'

Fix various glitches in "git gc" around reflog handling.

* ab/gc-reflog:
  gc: handle & check gc.reflogExpire config
  reflog tests: assert lack of early exit with expiry="never"
  reflog tests: test for the "points nowhere" warning
  reflog tests: make use of "test_config" idiom
  gc: refactor a "call me once" pattern
  gc: convert to using the_hash_algo
  gc: remove redundant check for gc_auto_threshold

builtin/gc.c

@@ -116,6 +116,19 @@ static void process_log_file_on_signal(int signo)
 	raise(signo);
 }
 
+static int gc_config_is_timestamp_never(const char *var)
+{
+	const char *value;
+	timestamp_t expire;
+
+	if (!git_config_get_value(var, &value) && value) {
+		if (parse_expiry_date(value, &expire))
+			die(_("failed to parse '%s' value '%s'"), var, value);
+		return expire == 0;
+	}
+	return 0;
+}
+
 static void gc_config(void)
 {
 	const char *value;
@@ -127,6 +140,10 @@ static void gc_config(void)
 			pack_refs = git_config_bool("gc.packrefs", value);
 	}
 
+	if (gc_config_is_timestamp_never("gc.reflogexpire") &&
+	    gc_config_is_timestamp_never("gc.reflogexpireunreachable"))
+		prune_reflogs = 0;
+
 	git_config_get_int("gc.aggressivewindow", &aggressive_window);
 	git_config_get_int("gc.aggressivedepth", &aggressive_depth);
 	git_config_get_int("gc.auto", &gc_auto_threshold);
@@ -156,9 +173,7 @@ static int too_many_loose_objects(void)
 	int auto_threshold;
 	int num_loose = 0;
 	int needed = 0;
-
+	const unsigned hexsz_loose = the_hash_algo->hexsz - 2;
-	if (gc_auto_threshold <= 0)
-		return 0;
 
 	dir = opendir(git_path("objects/17"));
 	if (!dir)
@@ -166,8 +181,8 @@ static int too_many_loose_objects(void)
 
 	auto_threshold = DIV_ROUND_UP(gc_auto_threshold, 256);
 	while ((ent = readdir(dir)) != NULL) {
-		if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
+		if (strspn(ent->d_name, "0123456789abcdef") != hexsz_loose ||
-		    ent->d_name[38] != '\0')
+		    ent->d_name[hexsz_loose] != '\0')
 			continue;
 		if (++num_loose > auto_threshold) {
 			needed = 1;
@@ -491,14 +506,20 @@ done:
 
 static void gc_before_repack(void)
 {
+	/*
+	 * We may be called twice, as both the pre- and
+	 * post-daemonized phases will call us, but running these
+	 * commands more than once is pointless and wasteful.
+	 */
+	static int done = 0;
+	if (done++)
+		return;
+
 	if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 		die(FAILED_RUN, pack_refs_cmd.argv[0]);
 
 	if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 		die(FAILED_RUN, reflog.argv[0]);
-
-	pack_refs = 0;
-	prune_reflogs = 0;
 }
 
 int cmd_gc(int argc, const char **argv, const char *prefix)

t/t1410-reflog.sh

@@ -232,25 +232,34 @@ test_expect_success '--expire=never' '
 '
 
 test_expect_success 'gc.reflogexpire=never' '
+	test_config gc.reflogexpire never &&
+	test_config gc.reflogexpireunreachable never &&
+
+	git reflog expire --verbose --all >output &&
+	test_line_count = 9 output &&
 
-	git config gc.reflogexpire never &&
-	git config gc.reflogexpireunreachable never &&
-	git reflog expire --verbose --all &&
 	git reflog refs/heads/master >output &&
 	test_line_count = 4 output
 '
 
 test_expect_success 'gc.reflogexpire=false' '
+	test_config gc.reflogexpire false &&
+	test_config gc.reflogexpireunreachable false &&
 
-	git config gc.reflogexpire false &&
-	git config gc.reflogexpireunreachable false &&
 	git reflog expire --verbose --all &&
 	git reflog refs/heads/master >output &&
-	test_line_count = 4 output &&
+	test_line_count = 4 output
 
-	git config --unset gc.reflogexpire &&
+'
-	git config --unset gc.reflogexpireunreachable
 
+test_expect_success 'git reflog expire unknown reference' '
+	test_config gc.reflogexpire never &&
+	test_config gc.reflogexpireunreachable never &&
+
+	test_must_fail git reflog expire master@{123} 2>stderr &&
+	test_i18ngrep "points nowhere" stderr &&
+	test_must_fail git reflog expire does-not-exist 2>stderr &&
+	test_i18ngrep "points nowhere" stderr
 '
 
 test_expect_success 'checkout should not delete log for packed ref' '

t/t6500-gc.sh

@@ -120,6 +120,25 @@ test_expect_success 'gc --quiet' '
 	test_must_be_empty stderr
 '
 
+test_expect_success 'gc.reflogExpire{Unreachable,}=never skips "expire" via "gc"' '
+	test_config gc.reflogExpire never &&
+	test_config gc.reflogExpireUnreachable never &&
+
+	GIT_TRACE=$(pwd)/trace.out git gc &&
+
+	# Check that git-pack-refs is run as a sanity check (done via
+	# gc_before_repack()) but that git-expire is not.
+	grep -E "^trace: (built-in|exec|run_command): git pack-refs --" trace.out &&
+	! grep -E "^trace: (built-in|exec|run_command): git reflog expire --" trace.out
+'
+
+test_expect_success 'one of gc.reflogExpire{Unreachable,}=never does not skip "expire" via "gc"' '
+	>trace.out &&
+	test_config gc.reflogExpire never &&
+	GIT_TRACE=$(pwd)/trace.out git gc &&
+	grep -E "^trace: (built-in|exec|run_command): git reflog expire --" trace.out
+'
+
 run_and_wait_for_auto_gc () {
 	# We read stdout from gc for the side effect of waiting until the
 	# background gc process exits, closing its fd 9.  Furthermore, the