Fix workdir iterators on empty directories

Creating a workdir iterator on a directory with absolutely
no files was returning an error (GIT_ENOTFOUND) instead of
an iterator for nothing.  This fixes that and includes two
new tests that cover that case.

src/iterator.c

@@ -660,6 +660,8 @@ int git_iterator_for_workdir_range(
 	int error;
 	workdir_iterator *wi;
 
+	assert(iter && repo);
+
 	if (git_repository_is_bare(repo)) {
 		giterr_set(GITERR_INVALID,
 			"Cannot scan working directory for bare repo");
@@ -680,10 +682,16 @@ int git_iterator_for_workdir_range(
 
 	wi->root_len = wi->path.size;
 
-	if ((error = workdir_iterator__expand_dir(wi)) < 0)
-		git_iterator_free((git_iterator *)wi);
-	else
-		*iter = (git_iterator *)wi;
+	if ((error = workdir_iterator__expand_dir(wi)) < 0) {
+		if (error == GIT_ENOTFOUND)
+			error = 0;
+		else {
+			git_iterator_free((git_iterator *)wi);
+			wi = NULL;
+		}
+	}
+
+	*iter = (git_iterator *)wi;
 
 	return error;
 }

tests-clar/status/worktree.c

@@ -447,3 +447,72 @@ void test_status_worktree__first_commit_in_progress(void)
 	git_index_free(index);
 	git_repository_free(repo);
 }
+
+
+
+void test_status_worktree__status_file_without_index_or_workdir(void)
+{
+	git_repository *repo;
+	unsigned int status = 0;
+	git_index *index;
+
+	cl_git_pass(p_mkdir("wd", 0777));
+
+	cl_git_pass(git_repository_open(&repo, cl_fixture("testrepo.git")));
+	cl_git_pass(git_repository_set_workdir(repo, "wd"));
+
+	cl_git_pass(git_index_open(&index, "empty-index"));
+	cl_assert_equal_i(0, git_index_entrycount(index));
+	git_repository_set_index(repo, index);
+
+	cl_git_pass(git_status_file(&status, repo, "branch_file.txt"));
+
+	cl_assert_equal_i(GIT_STATUS_INDEX_DELETED, status);
+
+	git_repository_free(repo);
+	git_index_free(index);
+	cl_git_pass(p_rmdir("wd"));
+}
+
+static void fill_index_wth_head_entries(git_repository *repo, git_index *index)
+{
+	git_oid oid;
+	git_commit *commit;
+	git_tree *tree;
+
+	cl_git_pass(git_reference_name_to_oid(&oid, repo, "HEAD"));
+	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
+	cl_git_pass(git_commit_tree(&tree, commit));
+
+	cl_git_pass(git_index_read_tree(index, tree));
+	cl_git_pass(git_index_write(index));
+
+	git_tree_free(tree);
+	git_commit_free(commit);
+}
+
+void test_status_worktree__status_file_with_clean_index_and_empty_workdir(void)
+{
+	git_repository *repo;
+	unsigned int status = 0;
+	git_index *index;
+
+	cl_git_pass(p_mkdir("wd", 0777));
+
+	cl_git_pass(git_repository_open(&repo, cl_fixture("testrepo.git")));
+	cl_git_pass(git_repository_set_workdir(repo, "wd"));
+
+	cl_git_pass(git_index_open(&index, "my-index"));
+	fill_index_wth_head_entries(repo, index);
+
+	git_repository_set_index(repo, index);
+
+	cl_git_pass(git_status_file(&status, repo, "branch_file.txt"));
+
+	cl_assert_equal_i(GIT_STATUS_WT_DELETED, status);
+
+	git_repository_free(repo);
+	git_index_free(index);
+	cl_git_pass(p_rmdir("wd"));
+	cl_git_pass(p_unlink("my-index"));
+}