builtin-notes: Add "remove" subcommand for removing existing notes

Using "git notes remove" is equivalent to specifying an empty note message.

The patch includes tests verifying correct behaviour of the new subcommand.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-notes.txt

@@ -8,14 +8,14 @@ git-notes - Add/inspect commit notes
 SYNOPSIS
 --------
 [verse]
-'git notes' (edit [-F <file> | -m <msg>] | show) [commit]
+'git notes' (edit [-F <file> | -m <msg>] | show | remove) [commit]
 
 DESCRIPTION
 -----------
-This command allows you to add notes to commit messages, without
-changing the commit.  To discern these notes from the message stored
-in the commit object, the notes are indented like the message, after
-an unindented line saying "Notes:".
+This command allows you to add/remove notes to/from commit messages,
+without changing the commit.  To discern these notes from the message
+stored in the commit object, the notes are indented like the message,
+after an unindented line saying "Notes:".
 
 To disable commit notes, you have to set the config variable
 core.notesRef to the empty string.  Alternatively, you can set it
@@ -32,6 +32,11 @@ edit::
 show::
 	Show the notes for a given commit (defaults to HEAD).
 
+remove::
+	Remove the notes for a given commit (defaults to HEAD).
+	This is equivalent to specifying an empty note message to
+	the `edit` subcommand.
+
 
 OPTIONS
 -------

builtin-notes.c

@@ -20,6 +20,7 @@
 static const char * const git_notes_usage[] = {
 	"git notes edit [-m <msg> | -F <file>] [<object>]",
 	"git notes show [<object>]",
+	"git notes remove [<object>]",
 	NULL
 };
 
@@ -197,9 +198,10 @@ int cmd_notes(int argc, const char **argv, const char *prefix)
 	struct notes_tree *t;
 	unsigned char object[20], new_note[20];
 	const unsigned char *note;
-	const char *object_ref, *logmsg;
+	const char *object_ref;
+	char logmsg[100];
 
-	int edit = 0, show = 0;
+	int edit = 0, show = 0, remove = 0;
 	const char *msgfile = NULL;
 	struct msg_arg msg = { 0, STRBUF_INIT };
 	struct option options[] = {
@@ -218,10 +220,22 @@ int cmd_notes(int argc, const char **argv, const char *prefix)
 		edit = 1;
 	else if (argc && !strcmp(argv[0], "show"))
 		show = 1;
+	else if (argc && !strcmp(argv[0], "remove"))
+		remove = 1;
 
-	if (edit + show != 1)
+	if (edit + show + remove != 1)
 		usage_with_options(git_notes_usage, options);
 
+	if ((msg.given || msgfile) && !edit) {
+		error("cannot use -m/-F options with %s subcommand.", argv[0]);
+		usage_with_options(git_notes_usage, options);
+	}
+
+	if (msg.given && msgfile) {
+		error("mixing -m and -F options is not allowed.");
+		usage_with_options(git_notes_usage, options);
+	}
+
 	object_ref = argc == 2 ? argv[1] : "HEAD";
 	if (argc > 2) {
 		error("too many parameters");
@@ -236,7 +250,7 @@ int cmd_notes(int argc, const char **argv, const char *prefix)
 
 	if (prefixcmp(t->ref, "refs/notes/"))
 		die("Refusing to %s notes in %s (outside of refs/notes/)",
-		    edit ? "edit" : "show", t->ref);
+		    argv[0], t->ref);
 
 	note = get_note(t, object);
 
@@ -250,35 +264,28 @@ int cmd_notes(int argc, const char **argv, const char *prefix)
 		return execv_git_cmd(show_args);
 	}
 
-	/* edit command */
+	/* edit/remove command */
 
-	if (msg.given || msgfile) {
-		if (msg.given && msgfile) {
-			error("mixing -m and -F options is not allowed.");
-			usage_with_options(git_notes_usage, options);
-		}
-		if (msg.given)
-			strbuf_addbuf(&buf, &(msg.buf));
-		else {
-			if (!strcmp(msgfile, "-")) {
-				if (strbuf_read(&buf, 0, 1024) < 0)
-					die_errno("cannot read '%s'", msgfile);
-			} else {
-				if (strbuf_read_file(&buf, msgfile, 1024) < 0)
-					die_errno("could not open or read '%s'",
-						msgfile);
-			}
-		}
+	if (remove)
+		strbuf_reset(&buf);
+	else if (msg.given)
+		strbuf_addbuf(&buf, &(msg.buf));
+	else if (msgfile) {
+		if (!strcmp(msgfile, "-")) {
+			if (strbuf_read(&buf, 0, 1024) < 0)
+				die_errno("cannot read '%s'", msgfile);
+		} else if (strbuf_read_file(&buf, msgfile, 1024) < 0)
+			die_errno("could not open or read '%s'", msgfile);
 	}
 
-	create_note(object, &buf, msg.given || msgfile, note, new_note);
-	if (is_null_sha1(new_note)) {
+	create_note(object, &buf, msg.given || msgfile || remove, note,
+		    new_note);
+	if (is_null_sha1(new_note))
 		remove_note(t, object);
-		logmsg = "Note removed by 'git notes edit'";
-	} else {
+	else
 		add_note(t, object, new_note, combine_notes_overwrite);
-		logmsg = "Note added by 'git notes edit'";
-	}
+	snprintf(logmsg, sizeof(logmsg), "Note %s by 'git notes %s'",
+		 is_null_sha1(new_note) ? "removed" : "added", argv[0]);
 	commit_notes(t, logmsg);
 
 	free_notes(t);

t/t3301-notes.sh

@@ -265,6 +265,33 @@ test_expect_success 'verify non-creation of note with -m ""' '
 	! git notes show
 '
 
+test_expect_success 'remove note with "git notes remove" (setup)' '
+	git notes remove HEAD^
+'
+
+cat > expect-rm-remove << EOF
+commit bd1753200303d0a0344be813e504253b3d98e74d
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:17:13 2005 -0700
+
+    5th
+
+commit 15023535574ded8b1a89052b32673f84cf9582b8
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:16:13 2005 -0700
+
+    4th
+EOF
+
+printf "\n" >> expect-rm-remove
+cat expect-multiline >> expect-rm-remove
+
+test_expect_success 'verify note removal with "git notes remove"' '
+	git log -4 > output &&
+	test_cmp expect-rm-remove output &&
+	! git notes show HEAD^
+'
+
 test_expect_success 'create other note on a different notes ref (setup)' '
 	: > a6 &&
 	git add a6 &&