notes remove: --stdin reads from the standard input

Teach the command to read object names to remove from the standard
input, in addition to the object names given from the command line.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-notes.txt

@@ -17,7 +17,7 @@ SYNOPSIS
 'git notes' merge [-v | -q] [-s <strategy> ] <notes_ref>
 'git notes' merge --commit [-v | -q]
 'git notes' merge --abort [-v | -q]
-'git notes' remove [--ignore-missing] [<object>...]
+'git notes' remove [--ignore-missing] [--stdin] [<object>...]
 'git notes' prune [-n | -v]
 'git notes' get-ref
 
@@ -159,6 +159,11 @@ OPTIONS
 	Do not consider it an error to request removing notes from an
 	object that does not have notes attached to it.
 
+--stdin::
+	Also read the object names to remove notes from from the standard
+	input (there is no reason you cannot combine this with object
+	names from the command line).
+
 -n::
 --dry-run::
 	Do not remove anything; just report the object names whose notes

builtin/notes.c

@@ -953,7 +953,7 @@ static int merge(int argc, const char **argv, const char *prefix)
 	return result < 0; /* return non-zero on conflicts */
 }
 
-#define MISSING_OK 1
+#define IGNORE_MISSING 1
 
 static int remove_one_note(struct notes_tree *t, const char *name, unsigned flag)
 {
@@ -966,16 +966,19 @@ static int remove_one_note(struct notes_tree *t, const char *name, unsigned flag
 		fprintf(stderr, _("Object %s has no note\n"), name);
 	else
 		fprintf(stderr, _("Removing note for object %s\n"), name);
-	return (flag & MISSING_OK) ? 0 : status;
+	return (flag & IGNORE_MISSING) ? 0 : status;
 }
 
 static int remove_cmd(int argc, const char **argv, const char *prefix)
 {
 	unsigned flag = 0;
+	int from_stdin = 0;
 	struct option options[] = {
 		OPT_BIT(0, "ignore-missing", &flag,
 			"attempt to remove non-existent note is not an error",
-			MISSING_OK),
+			IGNORE_MISSING),
+		OPT_BOOLEAN(0, "stdin", &from_stdin,
+			    "read object names from the standard input"),
 		OPT_END()
 	};
 	struct notes_tree *t;
@@ -986,14 +989,22 @@ static int remove_cmd(int argc, const char **argv, const char *prefix)
 
 	t = init_notes_check("remove");
 
-	if (!argc) {
+	if (!argc && !from_stdin) {
 		retval = remove_one_note(t, "HEAD", flag);
 	} else {
 		while (*argv) {
 			retval |= remove_one_note(t, *argv, flag);
 			argv++;
 		}
 	}
+	if (from_stdin) {
+		struct strbuf sb = STRBUF_INIT;
+		while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
+			strbuf_rtrim(&sb);
+			retval |= remove_one_note(t, sb.buf, flag);
+		}
+		strbuf_release(&sb);
+	}
 	if (!retval)
 		commit_notes(t, "Notes removed by 'git notes remove'");
 	free_notes(t);

t/t3301-notes.sh

@@ -475,6 +475,41 @@ test_expect_success 'removing with --ignore-missing but bogus ref' '
 	test "$before" = "$after"
 '
 
+test_expect_success 'remove reads from --stdin' '
+	before=$(git rev-parse --verify refs/notes/commits) &&
+	test_when_finished "git update-ref refs/notes/commits $before" &&
+
+	# We have only two -- add another and make sure it stays
+	git notes add -m "extra" &&
+	git notes list HEAD >after-removal-expect &&
+	git rev-parse HEAD^^ HEAD^^^ >input &&
+	git notes remove --stdin <input &&
+	git notes list | sed -e "s/ .*//" >actual &&
+	test_cmp after-removal-expect actual
+'
+
+test_expect_success 'remove --stdin is also atomic' '
+	before=$(git rev-parse --verify refs/notes/commits) &&
+	test_when_finished "git update-ref refs/notes/commits $before" &&
+	git rev-parse HEAD^^ HEAD^^^ HEAD^ >input &&
+	test_must_fail git notes remove --stdin <input &&
+	after=$(git rev-parse --verify refs/notes/commits) &&
+	test "$before" = "$after"
+'
+
+test_expect_success 'removing with --stdin --ignore-missing' '
+	before=$(git rev-parse --verify refs/notes/commits) &&
+	test_when_finished "git update-ref refs/notes/commits $before" &&
+
+	# We have only two -- add another and make sure it stays
+	git notes add -m "extra" &&
+	git notes list HEAD >after-removal-expect &&
+	git rev-parse HEAD^^ HEAD^^^ HEAD^ >input &&
+	git notes remove --ignore-missing --stdin <input &&
+	git notes list | sed -e "s/ .*//" >actual &&
+	test_cmp after-removal-expect actual
+'
+
 test_expect_success 'list notes with "git notes list"' '
 	git notes list > output &&
 	test_cmp expect output