diff-lib: ignore paths that are outside $cwd if --relative asked
For diff family commands, we can tell them to exclude changes outside
of some directories if --relative is requested.
In diff_unmerge(), NULL will be returned if the requested path is
outside of the interesting directories, thus we'll run into NULL
pointer dereference in run_diff_files when trying to dereference
its return value.
Checking for return value of diff_unmerge before dereferencing
is not sufficient, though. Since, diff engine will try to work on such
pathspec later.
Let's not run diff on those unintesting entries, instead.
As a side effect, by skipping like that, we can save some CPU cycles.
Reported-by: Thomas De Zeeuw <thomas@slight.dev>
Tested-by: Carlo Arenas <carenas@gmail.com>
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/diff-lib.c b/diff-lib.c
index b73cc18..b0c3836 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -116,6 +116,10 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
if (!ce_path_match(istate, ce, &revs->prune_data, NULL))
continue;
+ if (revs->diffopt.prefix &&
+ strncmp(ce->name, revs->diffopt.prefix, revs->diffopt.prefix_length))
+ continue;
+
if (ce_stage(ce)) {
struct combine_diff_path *dpath;
struct diff_filepair *pair;
