pathspec: allow to ignore SKIP_WORKTREE entries on index matching

Add a new enum parameter to `add_pathspec_matches_against_index()` and
`find_pathspecs_matching_against_index()`, allowing callers to specify
whether these function should attempt to match SKIP_WORKTREE entries or
not. This will be used in a future patch to make `git add` display a
warning when it is asked to update SKIP_WORKTREE entries.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/add.c

@@ -177,7 +177,8 @@ static char *prune_directory(struct dir_struct *dir, struct pathspec *pathspec,
 			*dst++ = entry;
 	}
 	dir->nr = dst - dir->entries;
-	add_pathspec_matches_against_index(pathspec, &the_index, seen);
+	add_pathspec_matches_against_index(pathspec, &the_index, seen,
+					   PS_HEED_SKIP_WORKTREE);
 	return seen;
 }
 
@@ -578,7 +579,8 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 		int i;
 
 		if (!seen)
-			seen = find_pathspecs_matching_against_index(&pathspec, &the_index);
+			seen = find_pathspecs_matching_against_index(&pathspec,
+					&the_index, PS_HEED_SKIP_WORKTREE);
 
 		/*
 		 * file_exists() assumes exact match

builtin/check-ignore.c

@@ -100,7 +100,8 @@ static int check_ignore(struct dir_struct *dir,
 	 * should not be ignored, in order to be consistent with
 	 * 'git status', 'git add' etc.
 	 */
-	seen = find_pathspecs_matching_against_index(&pathspec, &the_index);
+	seen = find_pathspecs_matching_against_index(&pathspec, &the_index,
+						     PS_HEED_SKIP_WORKTREE);
 	for (i = 0; i < pathspec.nr; i++) {
 		full_path = pathspec.items[i].match;
 		pattern = NULL;

pathspec.c

@@ -21,7 +21,8 @@
  */
 void add_pathspec_matches_against_index(const struct pathspec *pathspec,
 					const struct index_state *istate,
-					char *seen)
+					char *seen,
+					enum ps_skip_worktree_action sw_action)
 {
 	int num_unmatched = 0, i;
 
@@ -38,6 +39,8 @@ void add_pathspec_matches_against_index(const struct pathspec *pathspec,
 		return;
 	for (i = 0; i < istate->cache_nr; i++) {
 		const struct cache_entry *ce = istate->cache[i];
+		if (sw_action == PS_IGNORE_SKIP_WORKTREE && ce_skip_worktree(ce))
+			continue;
 		ce_path_match(istate, ce, pathspec, seen);
 	}
 }
@@ -51,10 +54,11 @@ void add_pathspec_matches_against_index(const struct pathspec *pathspec,
  * given pathspecs achieves against all items in the index.
  */
 char *find_pathspecs_matching_against_index(const struct pathspec *pathspec,
-					    const struct index_state *istate)
+					    const struct index_state *istate,
+					    enum ps_skip_worktree_action sw_action)
 {
 	char *seen = xcalloc(pathspec->nr, 1);
-	add_pathspec_matches_against_index(pathspec, istate, seen);
+	add_pathspec_matches_against_index(pathspec, istate, seen, sw_action);
 	return seen;
 }
 

pathspec.h

@@ -149,11 +149,17 @@ static inline int ps_strcmp(const struct pathspec_item *item,
 		return strcmp(s1, s2);
 }
 
+enum ps_skip_worktree_action {
+  PS_HEED_SKIP_WORKTREE = 0,
+  PS_IGNORE_SKIP_WORKTREE = 1
+};
 void add_pathspec_matches_against_index(const struct pathspec *pathspec,
 					const struct index_state *istate,
-					char *seen);
+					char *seen,
+					enum ps_skip_worktree_action sw_action);
 char *find_pathspecs_matching_against_index(const struct pathspec *pathspec,
-					    const struct index_state *istate);
+					    const struct index_state *istate,
+					    enum ps_skip_worktree_action sw_action);
 int match_pathspec_attrs(const struct index_state *istate,
 			 const char *name, int namelen,
 			 const struct pathspec_item *item);