Subject: Re: [PATCH] portability: allow building in systems without d_type

From: Junio C Hamano <[email-masked]>
Date: Wed, 18 Jun 2025 11:20:50 -0700

Carlo Marcelo Arenas Belón <[email-masked]> writes:

> Since 09fb155f11 (diff --no-index: support limiting by pathspec,
> 2025-05-21) will fail to build in platforms that don't have a
> d_type member on their struct dirent (ex: AIX, NonStop).
>
> Use the DTYPE() macro instead of a nake reference to d_type.

This may allow you to compile and build, but does the resulting
binary do what you want it to?

>  			if (!match_leading_pathspec(NULL, pathspec,
>  						    match.buf, match.len,
> -						    0, NULL, e->d_type == DT_DIR ? 1 : 0))
> +						    0, NULL, DTYPE(e) == DT_DIR ? 1 : 0))

On a platform without d_type member, DTYPE() macro gives DT_UNKNOWN
that is not DT_DIR, so essentially you are always passing 0 even
when you are looking at a directory (in which case you must pass 1)
to match_leading_pathspec().

So I somehow doubt this is a correct fix.

I do not know if get_dtype() helper function is easily applicable to
this codepath, so I wrote this in a longhand...

 diff-no-index.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git c/diff-no-index.c w/diff-no-index.c
index 7c95222ba6..677df91fc5 100644
--- c/diff-no-index.c
+++ w/diff-no-index.c
@@ -41,12 +41,28 @@ static int read_directory_contents(const char *path, struct string_list *list,
 
 	while ((e = readdir_skip_dot_and_dotdot(dir))) {
 		if (pathspec) {
+			int is_dir = 0;
+
 			strbuf_setlen(&match, len);
 			strbuf_addstr(&match, e->d_name);
+			if (dtype != DT_UNKNOWN) {
+				is_dir = dtype == DT_DIR;
+			} else {
+				struct stat st;
+				struct strbuf pathbuf = STRBUF_INIT;
+				strbuf_addstr(&pathbuf, path);
+				strbuf_complete(&pathbuf, '/');
+				strbuf_addstr(&pathbuf, e->d_name);
+				if (!lstat(&st, pathbuf.buf))
+					is_dir = S_ISDIR(st.st_mode);
+				else
+					; /* punt */
+				strbuf_release(&pathbuf);
+			}
 
 			if (!match_leading_pathspec(NULL, pathspec,
 						    match.buf, match.len,
-						    0, NULL, DTYPE(e) == DT_DIR ? 1 : 0))
+						    0, NULL, is_dir))
 				continue;
 		}