refs: make rev-parse --quiet actually quiet

When a reflog is deleted, e.g. when "git stash" clears its stashes,
"git rev-parse --verify --quiet" dies:

	fatal: Log for refs/stash is empty.

The reason is that the get_sha1() code path does not allow us
to suppress this message.

Pass the flags bitfield through get_sha1_with_context() so that
read_ref_at() can suppress the message.

Use get_sha1_with_context1() instead of get_sha1() in rev-parse
so that the --quiet flag is honored.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

6 files changed, 58 insertions, 16 deletions

diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index c911b456d..35d3c43ed 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -508,7 +508,9 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 	int has_dashdash = 0;
 	int output_prefix = 0;
 	unsigned char sha1[20];
+	unsigned int flags = 0;
 	const char *name = NULL;
+	struct object_context unused;
 
 	if (argc > 1 && !strcmp("--parseopt", argv[1]))
 		return cmd_parseopt(argc - 1, argv + 1, prefix);
@@ -596,6 +598,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 			}
 			if (!strcmp(arg, "--quiet") || !strcmp(arg, "-q")) {
 				quiet = 1;
+				flags |= GET_SHA1_QUIETLY;
 				continue;
 			}
 			if (!strcmp(arg, "--short") ||
@@ -818,7 +821,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 			name++;
 			type = REVERSED;
 		}
-		if (!get_sha1(name, sha1)) {
+		if (!get_sha1_with_context(name, flags, sha1, &unused)) {
 			if (verify)
 				revs_count++;
 			else
diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index 298c95e3f..46498e111 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -723,6 +723,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 		char nth_desc[256];
 		char *ref;
 		int base = 0;
+		unsigned int flags = 0;
 
 		if (ac == 0) {
 			static const char *fake_av[2];
@@ -749,7 +750,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 				/* Ah, that is a date spec... */
 				unsigned long at;
 				at = approxidate(reflog_base);
-				read_ref_at(ref, at, -1, sha1, NULL,
+				read_ref_at(ref, flags, at, -1, sha1, NULL,
 					    NULL, NULL, &base);
 			}
 		}
@@ -760,7 +761,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 			unsigned long timestamp;
 			int tz;
 
-			if (read_ref_at(ref, 0, base+i, sha1, &logmsg,
+			if (read_ref_at(ref, flags, 0, base+i, sha1, &logmsg,
 					&timestamp, &tz, NULL)) {
 				reflog = i;
 				break;
diff --git a/refs.c b/refs.c
index 2ce5d6909..9e405f9e4 100644
--- a/refs.c
+++ b/refs.c
@@ -3108,7 +3108,7 @@ static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
 	return 1;
 }
 
-int read_ref_at(const char *refname, unsigned long at_time, int cnt,
+int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
 		unsigned char *sha1, char **msg,
 		unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
 {
@@ -3126,8 +3126,12 @@ int read_ref_at(const char *refname, unsigned long at_time, int cnt,
 
 	for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
 
-	if (!cb.reccnt)
-		die("Log for %s is empty.", refname);
+	if (!cb.reccnt) {
+		if (flags & GET_SHA1_QUIETLY)
+			exit(128);
+		else
+			die("Log for %s is empty.", refname);
+	}
 	if (cb.found_it)
 		return 0;
 
diff --git a/refs.h b/refs.h
index 68c577016..0ca60599b 100644
--- a/refs.h
+++ b/refs.h
@@ -206,7 +206,8 @@ extern int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1, cons
 int log_ref_setup(const char *refname, char *logfile, int bufsize);
 
 /** Reads log for the value of ref during at_time. **/
-extern int read_ref_at(const char *refname, unsigned long at_time, int cnt,
+extern int read_ref_at(const char *refname, unsigned int flags,
+		       unsigned long at_time, int cnt,
 		       unsigned char *sha1, char **msg,
 		       unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);
 
diff --git a/sha1_name.c b/sha1_name.c
index 7098b10e3..5b004f513 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -432,7 +432,8 @@ static inline int upstream_mark(const char *string, int len)
 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 
-static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
+static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
+			  unsigned int flags)
 {
 	static const char *warn_msg = "refname '%.*s' is ambiguous.";
 	static const char *object_name_msg = N_(
@@ -511,7 +512,7 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 	if (!refs_found)
 		return -1;
 
-	if (warn_ambiguous_refs &&
+	if (warn_ambiguous_refs && !(flags & GET_SHA1_QUIETLY) &&
 	    (refs_found > 1 ||
 	     !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 		warning(warn_msg, len, str);
@@ -545,7 +546,7 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 				return -1;
 			}
 		}
-		if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
+		if (read_ref_at(real_ref, flags, at_time, nth, sha1, NULL,
 				&co_time, &co_tz, &co_cnt)) {
 			if (!len) {
 				if (starts_with(real_ref, "refs/heads/")) {
@@ -557,11 +558,16 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 					len = 4;
 				}
 			}
-			if (at_time)
-				warning("Log for '%.*s' only goes "
-					"back to %s.", len, str,
-					show_date(co_time, co_tz, DATE_RFC2822));
-			else {
+			if (at_time) {
+				if (!(flags & GET_SHA1_QUIETLY)) {
+					warning("Log for '%.*s' only goes "
+						"back to %s.", len, str,
+						show_date(co_time, co_tz, DATE_RFC2822));
+				}
+			} else {
+				if (flags & GET_SHA1_QUIETLY) {
+					exit(128);
+				}
 				die("Log for '%.*s' only has %d entries.",
 				    len, str, co_cnt);
 			}
@@ -801,7 +807,7 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned l
 	if (!ret)
 		return 0;
 
-	ret = get_sha1_basic(name, len, sha1);
+	ret = get_sha1_basic(name, len, sha1, lookup_flags);
 	if (!ret)
 		return 0;
 
diff --git a/t/t1503-rev-parse-verify.sh b/t/t1503-rev-parse-verify.sh
index d1f93b340..823fe1d79 100755
--- a/t/t1503-rev-parse-verify.sh
+++ b/t/t1503-rev-parse-verify.sh
@@ -83,6 +83,33 @@ test_expect_success 'fails silently when using -q' '
 	test_must_be_empty error
 '
 
+test_expect_success 'fails silently when using -q with deleted reflogs' '
+	ref=$(git rev-parse HEAD) &&
+	: >.git/logs/refs/test &&
+	git update-ref -m "message for refs/test" refs/test "$ref" &&
+	git reflog delete --updateref --rewrite refs/test@{0} &&
+	test_must_fail git rev-parse -q --verify refs/test@{0} >error 2>&1 &&
+	test_must_be_empty error
+'
+
+test_expect_success 'fails silently when using -q with not enough reflogs' '
+	ref=$(git rev-parse HEAD) &&
+	: >.git/logs/refs/test2 &&
+	git update-ref -m "message for refs/test2" refs/test2 "$ref" &&
+	test_must_fail git rev-parse -q --verify refs/test2@{999} >error 2>&1 &&
+	test_must_be_empty error
+'
+
+test_expect_success 'succeeds silently with -q and reflogs that do not go far back enough in time' '
+	ref=$(git rev-parse HEAD) &&
+	: >.git/logs/refs/test3 &&
+	git update-ref -m "message for refs/test3" refs/test3 "$ref" &&
+	git rev-parse -q --verify refs/test3@{1.year.ago} >actual 2>error &&
+	test_must_be_empty error &&
+	echo "$ref" >expect &&
+	test_cmp expect actual
+'
+
 test_expect_success 'no stdout output on error' '
 	test -z "$(git rev-parse --verify)" &&
 	test -z "$(git rev-parse --verify foo)" &&