From: Jeff King <peff@peff.net>
Date: Sun, 26 Jul 2026 08:47:05 +0000 (-0400)
Subject: diff-lib: skip paths outside prefix in oneway_diff()
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=151726d3ca54cbd279d527dc048133ead5c8b582;p=thirdparty%2Fgit.git

diff-lib: skip paths outside prefix in oneway_diff()

Commit 8174627b3d (diff-lib: ignore paths that are outside $cwd if
--relative asked, 2021-08-22) taught run_diff_files() to skip entries
outside the requested prefix before processing them.

Do the same in oneway_diff(), which handles the diff-index code path.
The lower-level diff queue functions already reject such paths, but
checking here avoids unnecessary work and keeps them out of every
do_oneway_diff() code path.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

diff --git a/diff-lib.c b/diff-lib.c
index bcab7c8500..d07e5d8d5b 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -538,6 +538,11 @@ static int oneway_diff(const struct cache_entry * const *src,
 	if (!idx && !tree)
 		BUG("oneway_diff with neither idx nor tree");
 
+	if (revs->diffopt.prefix &&
+	    strncmp((idx ? idx : tree)->name, revs->diffopt.prefix,
+		    revs->diffopt.prefix_length))
+		return 0;
+
 	if (ce_path_match(revs->diffopt.repo->index,
 			  idx ? idx : tree,
 			  &revs->prune_data, NULL)) {