add -i: Fix running from a subdirectory

This fixes the pathspec interactive_add() passes to the underlying
git-add--interactive helper.  When the command was run from a
subdirectory, cmd_add() already has gone up to the toplevel of the work
tree, and the helper will be spawned from there.  The pathspec given on
the command line from the user needs to be adjusted for this.

This adds "validate_pathspec()" function in the callchain, but it does
not validate yet.  The function can be changed to barf if there are
unmatching pathspec given by the user, but that is not strictly
necessary.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-add.c

@@ -135,13 +135,29 @@ static void refresh(int verbose, const char **pathspec)
         free(seen);
 }
 
-int interactive_add(int argc, const char **argv)
+static const char **validate_pathspec(int argc, const char **argv, const char *prefix)
+{
+	const char **pathspec = get_pathspec(prefix, argv);
+
+	return pathspec;
+}
+
+int interactive_add(int argc, const char **argv, const char *prefix)
 {
 	int status;
-	const char **args = xcalloc(sizeof(const char *), (argc + 2));
+	const char **args;
+	const char **pathspec = NULL;
 
+	if (argc) {
+		pathspec = validate_pathspec(argc, argv, prefix);
+		if (!pathspec)
+			return -1;
+	}
+
+	args = xcalloc(sizeof(const char *), (argc + 2));
 	args[0] = "add--interactive";
-	memcpy(&(args[1]), argv, sizeof(const char *) * argc);
+	if (argc)
+		memcpy(&(args[1]), pathspec, sizeof(const char *) * argc);
 	args[argc + 1] = NULL;
 
 	status = run_command_v_opt(args, RUN_GIT_CMD);
@@ -177,7 +193,7 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, builtin_add_options,
 			  builtin_add_usage, 0);
 	if (add_interactive)
-		exit(interactive_add(argc, argv));
+		exit(interactive_add(argc, argv, prefix));
 
 	git_config(git_default_config);
 

builtin-commit.c

@@ -165,7 +165,7 @@ static char *prepare_index(int argc, const char **argv, const char *prefix)
 	const char **pathspec = NULL;
 
 	if (interactive) {
-		interactive_add(argc, argv);
+		interactive_add(argc, argv, prefix);
 		commit_style = COMMIT_AS_IS;
 		return get_index_file();
 	}

commit.h

@@ -113,7 +113,7 @@ extern struct commit_list *get_shallow_commits(struct object_array *heads,
 
 int in_merge_bases(struct commit *, struct commit **, int);
 
-extern int interactive_add(int argc, const char **argv);
+extern int interactive_add(int argc, const char **argv, const char *prefix);
 extern int rerere(void);
 
 static inline int single_parent(struct commit *commit)