git rev-parse -q --verify $SHA doesn't always quiet errors

git rev-parse -q --verify $SHA doesn't always quiet errors

[Kevin Ballard]

The -q flag to git rev-parse --verify is supposed to quiet all errors.
However it doesn't appear to quiet the "short SHA1 is ambiguous" error.

% cd Dev/git
% git rev-parse -q --verify e51d
error: short SHA1 e51d is ambiguous.

I took a quick look, and the error is being emitted deep within
sha1_name.c, far outside of any access to the -q flag. I'm not sure how
to go about fixing this. Does anyone have any ideas?

Alternatively, is there a better way to tell if a given string can
resolve into a full sha1 besides

  git rev-parse -q --verify "$word" 2>/dev/null

-Kevin Ballard

Re: git rev-parse -q --verify $SHA doesn't always quiet errors

[Jonathan Nieder]

Kevin Ballard wrote:

> % cd Dev/git
> % git rev-parse -q --verify e51d
> error: short SHA1 e51d is ambiguous.
> 
> I took a quick look, and the error is being emitted deep within
> sha1_name.c, far outside of any access to the -q flag.

Something to play with.  Sloppy, untested, but maybe it gives an idea
of what's possible.

diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index a5a1c86..13f099a 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -108,8 +108,17 @@ static void show_with_type(int type, const char *arg)
 	show(arg);
 }
 
+static void die_no_single_rev(int quiet)
+{
+	if (quiet)
+		exit(1);
+	else
+		die("Needed a single revision");
+}
+
 /* Output a revision, only if filter allows it */
-static void show_rev(int type, const unsigned char *sha1, const char *name)
+static void show_rev(int type, const unsigned char *sha1, const char *name,
+		     int verify, int quiet)
 {
 	if (!(filter & DO_REVS))
 		return;
@@ -137,6 +146,8 @@ static void show_rev(int type, const unsigned char *sha1, const char *name)
 				show_with_type(type, full);
 				break;
 			default: /* ambiguous */
+				if (verify)
+					die_no_single_rev(quiet);
 				error("refname '%s' is ambiguous", name);
 				break;
 			}
@@ -171,7 +182,7 @@ static int show_default(void)
 
 		def = NULL;
 		if (!get_sha1(s, sha1)) {
-			show_rev(NORMAL, sha1, s);
+			show_rev(NORMAL, sha1, s, 0, 0);
 			return 1;
 		}
 	}
@@ -180,13 +191,13 @@ static int show_default(void)
 
 static int show_reference(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 {
-	show_rev(NORMAL, sha1, refname);
+	show_rev(NORMAL, sha1, refname, 0, 0);
 	return 0;
 }
 
 static int anti_reference(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 {
-	show_rev(REVERSED, sha1, refname);
+	show_rev(REVERSED, sha1, refname, 0, 0);
 	return 0;
 }
 
@@ -234,8 +245,8 @@ static int try_difference(const char *arg)
 	if (dotdot == arg)
 		this = "HEAD";
 	if (!get_sha1(this, sha1) && !get_sha1(next, end)) {
-		show_rev(NORMAL, end, next);
-		show_rev(symmetric ? NORMAL : REVERSED, sha1, this);
+		show_rev(NORMAL, end, next, 0, 0);
+		show_rev(symmetric ? NORMAL : REVERSED, sha1, this, 0, 0);
 		if (symmetric) {
 			struct commit_list *exclude;
 			struct commit *a, *b;
@@ -245,7 +256,8 @@ static int try_difference(const char *arg)
 			while (exclude) {
 				struct commit_list *n = exclude->next;
 				show_rev(REVERSED,
-					 exclude->item->object.sha1,NULL);
+					 exclude->item->object.sha1,
+					 NULL, 0, 0);
 				free(exclude);
 				exclude = n;
 			}
@@ -277,11 +289,11 @@ static int try_parent_shorthands(const char *arg)
 		return 0;
 
 	if (!parents_only)
-		show_rev(NORMAL, sha1, arg);
+		show_rev(NORMAL, sha1, arg, 0, 0);
 	commit = lookup_commit_reference(sha1);
 	for (parents = commit->parents; parents; parents = parents->next)
 		show_rev(parents_only ? NORMAL : REVERSED,
-				parents->item->object.sha1, arg);
+				parents->item->object.sha1, arg, 0, 0);
 
 	return 1;
 }
@@ -429,14 +441,6 @@ static int cmd_sq_quote(int argc, const char **argv)
 	return 0;
 }
 
-static void die_no_single_rev(int quiet)
-{
-	if (quiet)
-		exit(1);
-	else
-		die("Needed a single revision");
-}
-
 static const char builtin_rev_parse_usage[] =
 "git rev-parse --parseopt [options] -- [<args>...]\n"
 "   or: git rev-parse --sq-quote [<arg>...]\n"
@@ -707,12 +711,15 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 			name++;
 			type = REVERSED;
 		}
-		if (!get_sha1(name, sha1)) {
-			if (verify)
-				revs_count++;
-			else
-				show_rev(type, sha1, name);
-			continue;
+		{
+			struct object_context dummy;
+			if (!get_sha1_with_context_2(name, sha1, &dummy, 1, NULL, quiet)) {
+				if (verify)
+					revs_count++;
+				else
+					show_rev(type, sha1, name, 0, 0);
+				continue;
+			}
 		}
 		if (verify)
 			die_no_single_rev(quiet);
@@ -723,7 +730,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 	}
 	if (verify) {
 		if (revs_count == 1) {
-			show_rev(type, sha1, name);
+			show_rev(type, sha1, name, verify, quiet);
 			return 0;
 		} else if (revs_count == 0 && show_default())
 			return 0;
diff --git a/cache.h b/cache.h
index 33decd9..2bef387 100644
--- a/cache.h
+++ b/cache.h
@@ -773,6 +773,7 @@ static inline int get_sha1_with_mode(const char *str, unsigned char *sha1, unsig
 	return get_sha1_with_mode_1(str, sha1, mode, 1, NULL);
 }
 extern int get_sha1_with_context_1(const char *name, unsigned char *sha1, struct object_context *orc, int gently, const char *prefix);
+extern int get_sha1_with_context_2(const char *name, unsigned char *sha1, struct object_context *orc, int gently, const char *prefix, int quietly);
 static inline int get_sha1_with_context(const char *str, unsigned char *sha1, struct object_context *orc)
 {
 	return get_sha1_with_context_1(str, sha1, orc, 1, NULL);
diff --git a/sha1_name.c b/sha1_name.c
index 484081d..5cefb75 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -611,7 +611,7 @@ static int get_describe_name(const char *name, int len, unsigned char *sha1)
 	return -1;
 }
 
-static int get_sha1_1(const char *name, int len, unsigned char *sha1)
+static int get_sha1_2(const char *name, int len, unsigned char *sha1, int quietly)
 {
 	int ret, has_suffix;
 	const char *cp;
@@ -656,7 +656,12 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 	if (!ret)
 		return 0;
 
-	return get_short_sha1(name, len, sha1, 0);
+	return get_short_sha1(name, len, sha1, quietly);
+}
+
+static int get_sha1_1(const char *name, int len, unsigned char *sha1)
+{
+	return get_sha1_2(name, len, sha1, 0);
 }
 
 /*
@@ -1046,9 +1051,9 @@ int get_sha1_with_mode_1(const char *name, unsigned char *sha1, unsigned *mode,
 	return ret;
 }
 
-int get_sha1_with_context_1(const char *name, unsigned char *sha1,
+int get_sha1_with_context_2(const char *name, unsigned char *sha1,
 			    struct object_context *oc,
-			    int gently, const char *prefix)
+			    int gently, const char *prefix, int quietly)
 {
 	int ret, bracket_depth;
 	int namelen = strlen(name);
@@ -1056,7 +1061,7 @@ int get_sha1_with_context_1(const char *name, unsigned char *sha1,
 
 	memset(oc, 0, sizeof(*oc));
 	oc->mode = S_IFINVALID;
-	ret = get_sha1_1(name, namelen, sha1);
+	ret = get_sha1_2(name, namelen, sha1, quietly);
 	if (!ret)
 		return ret;
 	/* sha1:path --> object name of path in ent sha1
@@ -1141,3 +1146,10 @@ int get_sha1_with_context_1(const char *name, unsigned char *sha1,
 	}
 	return ret;
 }
+
+int get_sha1_with_context_1(const char *name, unsigned char *sha1,
+			    struct object_context *oc,
+			    int gently, const char *prefix)
+{
+	return get_sha1_with_context_2(name, sha1, oc, gently, prefix, 0);
+}