Return the matched pathspec pattern in `git_pathspec_match_path`

Instead of returning directly the pattern as the return value, I used an
out parameter, because the function also tests if the passed pathspecs
vector is empty. If yes, it considers that the path "matches", but in
that case there is no matched pattern per se.

5 files changed, 31 insertions, 9 deletions

diff --git a/src/checkout.c b/src/checkout.c
index 40f5732ed..0ce283beb 100644
--- a/src/checkout.c
+++ b/src/checkout.c
@@ -224,7 +224,7 @@ static int checkout_action_wd_only(
 	if (!git_pathspec_match_path(
 			pathspec, wd->path,
 			(data->strategy & GIT_CHECKOUT_DISABLE_PATHSPEC_MATCH) != 0,
-			git_iterator_ignore_case(workdir)))
+			git_iterator_ignore_case(workdir), NULL))
 		return 0;
 
 	/* check if item is tracked in the index but not in the checkout diff */
diff --git a/src/diff.c b/src/diff.c
index 4b60935f0..3e8028551 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -47,6 +47,7 @@ static int diff_delta__from_one(
 	const git_index_entry *entry)
 {
 	git_diff_delta *delta;
+	const char *matched_pathspec;
 
 	if (status == GIT_DELTA_IGNORED &&
 		(diff->opts.flags & GIT_DIFF_INCLUDE_IGNORED) == 0)
@@ -59,7 +60,7 @@ static int diff_delta__from_one(
 	if (!git_pathspec_match_path(
 			&diff->pathspec, entry->path,
 			(diff->opts.flags & GIT_DIFF_DISABLE_PATHSPEC_MATCH) != 0,
-			(diff->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE) != 0))
+			(diff->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE) != 0, &matched_pathspec))
 		return 0;
 
 	delta = diff_delta__alloc(diff, status, entry->path);
@@ -419,13 +420,14 @@ static int maybe_modified(
 	unsigned int omode = oitem->mode;
 	unsigned int nmode = nitem->mode;
 	bool new_is_workdir = (new_iter->type == GIT_ITERATOR_TYPE_WORKDIR);
+	const char *matched_pathspec;
 
 	GIT_UNUSED(old_iter);
 
 	if (!git_pathspec_match_path(
 			&diff->pathspec, oitem->path,
 			(diff->opts.flags & GIT_DIFF_DISABLE_PATHSPEC_MATCH) != 0,
-			(diff->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE) != 0))
+			(diff->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE) != 0, &matched_pathspec))
 		return 0;
 
 	/* on platforms with no symlinks, preserve mode of existing symlinks */
diff --git a/src/index.c b/src/index.c
index 1e00dd3fa..f5bf954a8 100644
--- a/src/index.c
+++ b/src/index.c
@@ -1710,7 +1710,8 @@ int git_index_read_tree_match(
 		goto cleanup;
 
 	while (entry != NULL) {
-		if (git_pathspec_match_path(&pathspec, entry->path, false, false) &&
+		if (git_pathspec_match_path(
+				&pathspec, entry->path, false, false, NULL) &&
 			(error = git_index_add(index, entry)) < 0)
 			goto cleanup;
 
diff --git a/src/pathspec.c b/src/pathspec.c
index 2bde3ba5f..732180248 100644
--- a/src/pathspec.c
+++ b/src/pathspec.c
@@ -106,14 +106,21 @@ void git_pathspec_free(git_vector *vspec)
 
 /* match a path against the vectorized pathspec */
 bool git_pathspec_match_path(
-	git_vector *vspec, const char *path, bool disable_fnmatch, bool casefold)
+	git_vector *vspec,
+	const char *path,
+	bool disable_fnmatch,
+	bool casefold,
+	const char **matched_pathspec)
 {
-	unsigned int i;
+	size_t i;
 	git_attr_fnmatch *match;
 	int fnmatch_flags = 0;
 	int (*use_strcmp)(const char *, const char *);
 	int (*use_strncmp)(const char *, const char *, size_t);
 
+	if (matched_pathspec)
+		*matched_pathspec = NULL;
+
 	if (!vspec || !vspec->length)
 		return true;
 
@@ -143,8 +150,12 @@ bool git_pathspec_match_path(
 			path[match->length] == '/')
 			result = 0;
 
-		if (result == 0)
+		if (result == 0) {
+			if (matched_pathspec)
+				*matched_pathspec = match->pattern;
+
 			return (match->flags & GIT_ATTR_FNMATCH_NEGATIVE) ? false : true;
+		}
 	}
 
 	return false;
diff --git a/src/pathspec.h b/src/pathspec.h
index dde63c7d0..c44561520 100644
--- a/src/pathspec.h
+++ b/src/pathspec.h
@@ -25,8 +25,16 @@ extern int git_pathspec_init(
 /* free data from the pathspec vector */
 extern void git_pathspec_free(git_vector *vspec);
 
-/* match a path against the vectorized pathspec */
+/*
+ * Match a path against the vectorized pathspec.
+ * The matched pathspec is passed back into the `matched_pathspec` parameter,
+ * unless it is passed as NULL by the caller.
+ */
 extern bool git_pathspec_match_path(
-	git_vector *vspec, const char *path, bool disable_fnmatch, bool casefold);
+	git_vector *vspec,
+	const char *path,
+	bool disable_fnmatch,
+	bool casefold,
+	const char **matched_pathspec);
 
 #endif