Add a debug view of the "Affected Path" index to Differential

Summary:
Ref T13639. The "Affected Path" table is currently hard to inspect: there's no UI, and using MySQL just gives you a bunch of IDs.

Add a simple UI and a debug-mode link to it.

Test Plan:
{F8539098}

{F8539099}

Maniphest Tasks: T13639

Differential Revision: https://secure.phabricator.com/D21615

src/__phutil_library_map__.php

@@ -613,6 +613,7 @@ phutil_register_library_map(array(
     'DifferentialRevisionAcceptTransaction' => 'applications/differential/xaction/DifferentialRevisionAcceptTransaction.php',
     'DifferentialRevisionActionTransaction' => 'applications/differential/xaction/DifferentialRevisionActionTransaction.php',
     'DifferentialRevisionAffectedFilesHeraldField' => 'applications/differential/herald/DifferentialRevisionAffectedFilesHeraldField.php',
+    'DifferentialRevisionAffectedPathsController' => 'applications/differential/controller/DifferentialRevisionAffectedPathsController.php',
     'DifferentialRevisionAuthorHeraldField' => 'applications/differential/herald/DifferentialRevisionAuthorHeraldField.php',
     'DifferentialRevisionAuthorPackagesHeraldField' => 'applications/differential/herald/DifferentialRevisionAuthorPackagesHeraldField.php',
     'DifferentialRevisionAuthorProjectsHeraldField' => 'applications/differential/herald/DifferentialRevisionAuthorProjectsHeraldField.php',
@@ -6733,6 +6734,7 @@ phutil_register_library_map(array(
     'DifferentialRevisionAcceptTransaction' => 'DifferentialRevisionReviewTransaction',
     'DifferentialRevisionActionTransaction' => 'DifferentialRevisionTransactionType',
     'DifferentialRevisionAffectedFilesHeraldField' => 'DifferentialRevisionHeraldField',
+    'DifferentialRevisionAffectedPathsController' => 'DifferentialController',
     'DifferentialRevisionAuthorHeraldField' => 'DifferentialRevisionHeraldField',
     'DifferentialRevisionAuthorPackagesHeraldField' => 'DifferentialRevisionHeraldField',
     'DifferentialRevisionAuthorProjectsHeraldField' => 'DifferentialRevisionHeraldField',

src/applications/differential/application/PhabricatorDifferentialApplication.php

@@ -74,6 +74,8 @@ final class PhabricatorDifferentialApplication
             => 'DifferentialRevisionOperationController',
           'inlines/(?P<id>[1-9]\d*)/'
             => 'DifferentialRevisionInlinesController',
+          'paths/(?P<id>[1-9]\d*)/'
+            => 'DifferentialRevisionAffectedPathsController',
         ),
         'comment/' => array(
           'inline/' => array(

src/applications/differential/controller/DifferentialRevisionAffectedPathsController.php

@@ -0,0 +1,127 @@
+<?php
+
+final class DifferentialRevisionAffectedPathsController
+  extends DifferentialController {
+
+  public function handleRequest(AphrontRequest $request) {
+    $viewer = $this->getViewer();
+    $id = $request->getURIData('id');
+
+    $revision = id(new DifferentialRevisionQuery())
+      ->withIDs(array($id))
+      ->setViewer($viewer)
+      ->executeOne();
+    if (!$revision) {
+      return new Aphront404Response();
+    }
+
+    $table = new DifferentialAffectedPath();
+    $conn = $table->establishConnection('r');
+
+    $paths = queryfx_all(
+      $conn,
+      'SELECT * FROM %R WHERE revisionID = %d',
+      $table,
+      $revision->getID());
+
+    $repository_ids = array();
+    $path_ids = array();
+
+    foreach ($paths as $path) {
+      $repository_id = $path['repositoryID'];
+      $path_id = $path['pathID'];
+
+      $repository_ids[] = $repository_id;
+      $path_ids[] = $path_id;
+    }
+
+    $repository_ids = array_fuse($repository_ids);
+
+    if ($repository_ids) {
+      $repositories = id(new PhabricatorRepositoryQuery())
+        ->setViewer($viewer)
+        ->withIDs($repository_ids)
+        ->execute();
+      $repositories = mpull($repositories, null, 'getID');
+    } else {
+      $repositories = array();
+    }
+
+    $handles = $viewer->loadHandles(mpull($repositories, 'getPHID'));
+
+    $path_ids = array_fuse($path_ids);
+    if ($path_ids) {
+      $path_names = id(new DiffusionPathQuery())
+        ->withPathIDs($path_ids)
+        ->execute();
+    } else {
+      $path_names = array();
+    }
+
+    $rows = array();
+    foreach ($paths as $path) {
+      $repository_id = $path['repositoryID'];
+      $path_id = $path['pathID'];
+
+      $repository = idx($repositories, $repository_id);
+      if ($repository) {
+        $repository_phid = $repository->getPHID();
+        $repository_link = $handles[$repository_phid]->renderLink();
+      } else {
+        $repository_link = null;
+      }
+
+      $path_name = idx($path_names, $path_id);
+      if ($path_name !== null) {
+        $path_view = $path_name['path'];
+      } else {
+        $path_view = null;
+      }
+
+      $rows[] = array(
+        $repository_id,
+        $repository_link,
+        $path_id,
+        $path_view,
+      );
+    }
+
+    // Sort rows by path name.
+    $rows = isort($rows, 3);
+
+    $table_view = id(new AphrontTableView($rows))
+      ->setNoDataString(pht('This revision has no indexed affected paths.'))
+      ->setHeaders(
+        array(
+          pht('Repository ID'),
+          pht('Repository'),
+          pht('Path ID'),
+          pht('Path'),
+        ))
+      ->setColumnClasses(
+        array(
+          null,
+          null,
+          null,
+          'wide',
+        ));
+
+    $box_view = id(new PHUIObjectBoxView())
+      ->setHeaderText(pht('Affected Path Index'))
+      ->setTable($table_view);
+
+    $crumbs = $this->buildApplicationCrumbs()
+      ->addTextCrumb($revision->getMonogram(), $revision->getURI())
+      ->addTextCrumb(pht('Affected Path Index'));
+
+    return $this->newPage()
+      ->setCrumbs($crumbs)
+      ->setTitle(
+        array(
+          $revision->getMonogram(),
+          pht('Affected Path Index'),
+        ))
+      ->appendChild($box_view);
+  }
+
+}

src/applications/system/events/PhabricatorSystemDebugUIEventListener.php

@@ -44,6 +44,16 @@ final class PhabricatorSystemDebugUIEventListener
       ->setName(pht('View Hovercard'))
       ->setHref(urisprintf('/search/hovercard/?names=%s', $phid));
 
+    if ($object instanceof DifferentialRevision) {
+      $submenu[] = id(new PhabricatorActionView())
+        ->setIcon('fa-database')
+        ->setName(pht('View Affected Path Index'))
+        ->setHref(
+          urisprintf(
+            '/differential/revision/paths/%s/',
+            $object->getID()));
+    }
+
     $developer_action = id(new PhabricatorActionView())
       ->setName(pht('Advanced/Developer...'))
       ->setIcon('fa-magic')