Fix a dirname() edge case in Diffusion

Summary:
dirname('x') returns '.', not '/'; this caused some issues for repositories with
files at the root.

There are some cases in the parsers where I should probably swap this out too
but I'll wait until I'm doing some more rigorous testing since that stuff is a
bit fragile and this fixes an immediate issue.

Test Plan: Ran unit tests. Viewed a file at root level in a test repository.

Reviewers: jungejason, nh, tuomaspelkonen, aran

Reviewed By: nh

CC: aran, nh

Differential Revision: 932

src/__phutil_library_map__.php

@@ -262,6 +262,7 @@ phutil_register_library_map(array(
     'DiffusionPathChangeQuery' => 'applications/diffusion/query/pathchange/base',
     'DiffusionPathCompleteController' => 'applications/diffusion/controller/pathcomplete',
     'DiffusionPathIDQuery' => 'applications/diffusion/query/pathid/base',
+    'DiffusionPathQueryTestCase' => 'applications/diffusion/query/pathid/base/__tests__',
     'DiffusionPathValidateController' => 'applications/diffusion/controller/pathvalidate',
     'DiffusionRepositoryController' => 'applications/diffusion/controller/repository',
     'DiffusionRepositoryPath' => 'applications/diffusion/data/repositorypath',
@@ -918,6 +919,7 @@ phutil_register_library_map(array(
     'DiffusionHomeController' => 'DiffusionController',
     'DiffusionLastModifiedController' => 'DiffusionController',
     'DiffusionPathCompleteController' => 'DiffusionController',
+    'DiffusionPathQueryTestCase' => 'PhabricatorTestCase',
     'DiffusionPathValidateController' => 'DiffusionController',
     'DiffusionRepositoryController' => 'DiffusionController',
     'DiffusionSvnBrowseQuery' => 'DiffusionBrowseQuery',

src/applications/diffusion/query/browse/svn/DiffusionSvnBrowseQuery.php

@@ -36,7 +36,7 @@ final class DiffusionSvnBrowseQuery extends DiffusionBrowseQuery {
 
     $conn_r = $repository->establishConnection('r');
 
-    $parent_path = dirname($path);
+    $parent_path = DiffusionPathIDQuery::getParentPath($path);
     $path_query = new DiffusionPathIDQuery(
       array(
         $path,

src/applications/diffusion/query/pathid/base/DiffusionPathIDQuery.php

@@ -53,4 +53,9 @@ final class DiffusionPathIDQuery {
     return '/'.trim($path, '/');
   }
 
+  public static function getParentPath($path) {
+    $path = self::normalizePath($path);
+    return dirname($path);
+  }
+
 }

src/applications/diffusion/query/pathid/base/__tests__/DiffusionPathQueryTestCase.php

@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+final class DiffusionPathQueryTestCase extends PhabricatorTestCase {
+
+  public function testParentEdgeCases() {
+    $this->assertEqual(
+      '/',
+      DiffusionPathIDQuery::getParentPath('/'),
+      'Parent of /');
+    $this->assertEqual(
+      '/',
+      DiffusionPathIDQuery::getParentPath('x.txt'),
+      'Parent of x.txt');
+    $this->assertEqual(
+      '/a',
+      DiffusionPathIDQuery::getParentPath('/a/b'),
+      'Parent of /a/b');
+  }
+
+}
+

src/applications/diffusion/query/pathid/base/__tests__/__init__.php

@@ -0,0 +1,13 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'applications/diffusion/query/pathid/base');
+phutil_require_module('phabricator', 'infrastructure/testing/testcase');
+
+
+phutil_require_source('DiffusionPathQueryTestCase.php');