notes-merge: use opendir/readdir instead of using read_directory()

notes_merge_commit() only needs to list all entries (non-recursively)
under a directory, which can be easily accomplished with
opendir/readdir and would be more lightweight than read_directory().

read_directory() is designed to list paths inside a working
directory. Using it outside of its scope may lead to undesired effects.

Apparently, one of the undesired effects of read_directory() is that it
doesn't deal with being given absolute paths. This creates problems for
notes_merge_commit() when git_path() returns an absolute path, which
happens when the current working directory is in a subdirectory of the
.git directory.

Originally-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Updated-by:  Johan Herland <johan@herland.net>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

notes-merge.c

@@ -687,51 +687,60 @@ int notes_merge_commit(struct notes_merge_options *o,
 {
 	/*
 	 * Iterate through files in .git/NOTES_MERGE_WORKTREE and add all
-	 * found notes to 'partial_tree'. Write the updates notes tree to
+	 * found notes to 'partial_tree'. Write the updated notes tree to
 	 * the DB, and commit the resulting tree object while reusing the
 	 * commit message and parents from 'partial_commit'.
 	 * Finally store the new commit object SHA1 into 'result_sha1'.
 	 */
-	struct dir_struct dir;
-	char *path = xstrdup(git_path(NOTES_MERGE_WORKTREE "/"));
-	int path_len = strlen(path), i;
+	DIR *dir;
+	struct dirent *e;
+	struct strbuf path = STRBUF_INIT;
 	char *msg = strstr(partial_commit->buffer, "\n\n");
 	struct strbuf sb_msg = STRBUF_INIT;
+	int baselen;
 
+	strbuf_addstr(&path, git_path(NOTES_MERGE_WORKTREE));
 	if (o->verbosity >= 3)
-		printf("Committing notes in notes merge worktree at %.*s\n",
-			path_len - 1, path);
+		printf("Committing notes in notes merge worktree at %s\n",
+			path.buf);
 
 	if (!msg || msg[2] == '\0')
 		die("partial notes commit has empty message");
 	msg += 2;
 
-	memset(&dir, 0, sizeof(dir));
-	read_directory(&dir, path, path_len, NULL);
-	for (i = 0; i < dir.nr; i++) {
-		struct dir_entry *ent = dir.entries[i];
+	dir = opendir(path.buf);
+	if (!dir)
+		die_errno("could not open %s", path.buf);
+
+	strbuf_addch(&path, '/');
+	baselen = path.len;
+	while ((e = readdir(dir)) != NULL) {
 		struct stat st;
-		const char *relpath = ent->name + path_len;
 		unsigned char obj_sha1[20], blob_sha1[20];
 
-		if (ent->len - path_len != 40 || get_sha1_hex(relpath, obj_sha1)) {
+		if (is_dot_or_dotdot(e->d_name))
+			continue;
+
+		if (strlen(e->d_name) != 40 || get_sha1_hex(e->d_name, obj_sha1)) {
 			if (o->verbosity >= 3)
-				printf("Skipping non-SHA1 entry '%s'\n",
-								ent->name);
+				printf("Skipping non-SHA1 entry '%s%s'\n",
+					path.buf, e->d_name);
 			continue;
 		}
 
+		strbuf_addstr(&path, e->d_name);
 		/* write file as blob, and add to partial_tree */
-		if (stat(ent->name, &st))
-			die_errno("Failed to stat '%s'", ent->name);
-		if (index_path(blob_sha1, ent->name, &st, HASH_WRITE_OBJECT))
-			die("Failed to write blob object from '%s'", ent->name);
+		if (stat(path.buf, &st))
+			die_errno("Failed to stat '%s'", path.buf);
+		if (index_path(blob_sha1, path.buf, &st, HASH_WRITE_OBJECT))
+			die("Failed to write blob object from '%s'", path.buf);
 		if (add_note(partial_tree, obj_sha1, blob_sha1, NULL))
 			die("Failed to add resolved note '%s' to notes tree",
-			    ent->name);
+			    path.buf);
 		if (o->verbosity >= 4)
 			printf("Added resolved note for object %s: %s\n",
 				sha1_to_hex(obj_sha1), sha1_to_hex(blob_sha1));
+		strbuf_setlen(&path, baselen);
 	}
 
 	strbuf_attach(&sb_msg, msg, strlen(msg), strlen(msg) + 1);
@@ -740,7 +749,8 @@ int notes_merge_commit(struct notes_merge_options *o,
 	if (o->verbosity >= 4)
 		printf("Finalized notes merge commit: %s\n",
 			sha1_to_hex(result_sha1));
-	free(path);
+	strbuf_release(&path);
+	closedir(dir);
 	return 0;
 }
 

t/t3310-notes-merge-manual-resolve.sh

@@ -558,7 +558,7 @@ foo
 bar
 EOF
 
-test_expect_failure 'switch cwd before committing notes merge' '
+test_expect_success 'switch cwd before committing notes merge' '
 	git notes add -m foo HEAD &&
 	git notes --ref=other add -m bar HEAD &&
 	test_must_fail git notes merge refs/notes/other &&