Re: [PATCH] gitignore(5): Allow "foo/" in ignore list to match directory "foo"

[Jeff King <peff@peff.net>]

On Thu, Jan 31, 2008 at 01:17:48AM -0800, Junio C Hamano wrote:

> A downside is that the recursive directory walk may need to run
> lstat(2) more often on systems whose "struct dirent" do not give
> the type of the entry; earlier it did not have to do so for an
> excluded path, but we now need to figure out if a path is a
> directory before deciding to exclude it.  This is especially bad

You can at least lazily do the stat so that only users of foo/ need to
pay the penalty. Something like this (completely untested):

diff --git a/dir.c b/dir.c
index a4f8c25..9487908 100644
--- a/dir.c
+++ b/dir.c
@@ -17,6 +17,7 @@ struct path_simplify {
 static int read_directory_recursive(struct dir_struct *dir,
 	const char *path, const char *base, int baselen,
 	int check_only, const struct path_simplify *simplify);
+static int get_dtype(struct dirent *de, const char *path, int try_stat);
 
 int common_prefix(const char **pathspec)
 {
@@ -288,9 +289,12 @@ static int excluded_1(const char *pathname,
 			const char *exclude = x->pattern;
 			int to_exclude = x->to_exclude;
 
-			if ((x->flags & EXC_FLAG_MUSTBEDIR) &&
-			    (dtype != DT_DIR))
-				continue;
+			if (x->flags & EXC_FLAG_MUSTBEDIR) {
+				if (dtype == DT_UNKNOWN)
+					dtype = get_dtype(NULL, pathname, 1);
+				if (dtype != DT_DIR)
+					continue;
+			}
 
 			if (x->flags & EXC_FLAG_NODIR) {
 				/* match basename */
@@ -527,13 +531,15 @@ static int in_pathspec(const char *path, int len, const struct path_simplify *si
 	return 0;
 }
 
-static int get_dtype(struct dirent *de, const char *path)
+static int get_dtype(struct dirent *de, const char *path, int try_stat)
 {
-	int dtype = DTYPE(de);
+	int dtype = de ? DTYPE(de) : DT_UNKNOWN;
 	struct stat st;
 
 	if (dtype != DT_UNKNOWN)
 		return dtype;
+	if (!try_stat)
+		return DT_UNKNOWN;
 	if (lstat(path, &st))
 		return dtype;
 	if (S_ISREG(st.st_mode))
@@ -581,7 +587,7 @@ static int read_directory_recursive(struct dir_struct *dir, const char *path, co
 			if (simplify_away(fullname, baselen + len, simplify))
 				continue;
 
-			dtype = get_dtype(de, fullname);
+			dtype = get_dtype(de, fullname, 0);
 			exclude = excluded(dir, fullname, dtype);
 			if (exclude && dir->collect_ignored
 			    && in_pathspec(fullname, baselen + len, simplify))