Don't report status on named pipes

Git skips entries in directories that are not S_ISDIR, S_ISREG, or
S_ISLNK, so let's make libgit2 do the same thing.

src/path.c

@@ -1110,28 +1110,29 @@ int git_path_dirload_with_stat(
 
 		if ((error = git_buf_joinpath(&full, full.ptr, ps->path)) < 0 ||
 			(error = git_path_lstat(full.ptr, &ps->st)) < 0) {
+
 			if (error == GIT_ENOTFOUND) {
-				giterr_clear();
-				error = 0;
+				/* file was removed between readdir and lstat */
 				git_vector_remove(contents, i--);
-				continue;
-			}
+			} else {
 				/* Treat the file as unreadable if we get any other error */
-			if (error != 0) {
-				giterr_clear();
-				error = 0;
 				memset(&ps->st, 0, sizeof(ps->st));
 				ps->st.st_mode = GIT_FILEMODE_UNREADABLE;
-				continue;
 			}
 
-			break;
+			giterr_clear();
+			error = 0;
+			continue;
 		}
 
 		if (S_ISDIR(ps->st.st_mode)) {
 			ps->path[ps->path_len++] = '/';
 			ps->path[ps->path_len] = '\0';
 		}
+		else if (!S_ISREG(ps->st.st_mode) && !S_ISLNK(ps->st.st_mode)) {
+			/* skip everything but dirs, plain files, and symlinks */
+			git_vector_remove(contents, i--);
+		}
 	}
 
 	/* sort now that directory suffix is added */

tests/repo/iterator.c

@@ -960,3 +960,35 @@ void test_repo_iterator__fs_preserves_error(void)
 
 	git_iterator_free(i);
 }
+
+void test_repo_iterator__skips_fifos_and_such(void)
+{
+#ifndef GIT_WIN32
+	git_iterator *i;
+	const git_index_entry *e;
+
+	g_repo = cl_git_sandbox_init("empty_standard_repo");
+
+	cl_must_pass(p_mkdir("empty_standard_repo/dir", 0777));
+	cl_git_mkfile("empty_standard_repo/file", "not me");
+
+	cl_assert(!mkfifo("empty_standard_repo/fifo", 0777));
+	cl_assert(!access("empty_standard_repo/fifo", F_OK));
+
+	cl_git_pass(git_iterator_for_filesystem(
+		&i, "empty_standard_repo", GIT_ITERATOR_INCLUDE_TREES |
+		GIT_ITERATOR_DONT_AUTOEXPAND, NULL, NULL));
+
+	cl_git_pass(git_iterator_advance(&e, i)); /* .git */
+	cl_assert(S_ISDIR(e->mode));
+	cl_git_pass(git_iterator_advance(&e, i)); /* dir */
+	cl_assert(S_ISDIR(e->mode));
+	/* skips fifo */
+	cl_git_pass(git_iterator_advance(&e, i)); /* file */
+	cl_assert(S_ISREG(e->mode));
+
+	cl_assert_equal_i(GIT_ITEROVER, git_iterator_advance(&e, i));
+
+	git_iterator_free(i);
+#endif
+}