Added a link from a diff view to diff's revision if there is one.

Summary:
The diff view page should point to the revision, if the diff has
already been attached to one. The form to select the revision was also
removed in this case.

Let's me know if it should be possible to reattach a diff to a different
revision.

Test Plan:
Tested that a new diff created with '--preview' option was not attached to
any revision. After attaching the diff manually, made sure that the diff view
page
showed the link to the revision correctly.

Reviewed By: epriestley
Reviewers: jungejason, epriestley
CC: aran, epriestley
Differential Revision: 216

src/applications/differential/controller/diffview/DifferentialDiffViewController.php

@@ -32,58 +32,72 @@ class DifferentialDiffViewController extends DifferentialController {
       return new Aphront404Response();
     }
 
-    $action_panel = new AphrontPanelView();
-    $action_panel->setHeader('Preview Diff');
-    $action_panel->setWidth(AphrontPanelView::WIDTH_WIDE);
-    $action_panel->appendChild(
-      '<p class="aphront-panel-instructions">Review the diff for correctness. '.
-      'When you are satisfied, either <strong>create a new revision</strong> '.
-      'or <strong>update an existing revision</strong>.');
+    if ($diff->getRevisionID()) {
+      $top_panel = new AphrontPanelView();
+      $top_panel->setWidth(AphrontPanelView::WIDTH_WIDE);
+      $link = phutil_render_tag(
+        'a',
+        array(
+          'href' => PhabricatorEnv::getURI('/D'.$diff->getRevisionID()),
+        ),
+        phutil_escape_html('D'.$diff->getRevisionID()));
+      $top_panel->appendChild("<h1>This diff belongs to revision {$link}</h1>");
+    } else {
+      $action_panel = new AphrontPanelView();
+      $action_panel->setHeader('Preview Diff');
+      $action_panel->setWidth(AphrontPanelView::WIDTH_WIDE);
+      $action_panel->appendChild(
+        '<p class="aphront-panel-instructions">Review the diff for '.
+        'correctness. When you are satisfied, either <strong>create a new '.
+        'revision</strong> or <strong>update an existing revision</strong>.');
 
-    // TODO: implmenent optgroup support in AphrontFormSelectControl?
-    $select = array();
-    $select[] = '<optgroup label="Create New Revision">';
-    $select[] = '<option value="">Create a new Revision...</option>';
-    $select[] = '</optgroup>';
-
-    $revision_data = new DifferentialRevisionListData(
-      DifferentialRevisionListData::QUERY_OPEN_OWNED,
-      array($request->getUser()->getPHID()));
-    $revisions = $revision_data->loadRevisions();
-
-    if ($revisions) {
-      $select[] = '<optgroup label="Update Existing Revision">';
-      foreach ($revisions as $revision) {
-        $select[] = phutil_render_tag(
-          'option',
-          array(
-            'value' => $revision->getID(),
-          ),
-          phutil_escape_html($revision->getTitle()));
-      }
+      // TODO: implmenent optgroup support in AphrontFormSelectControl?
+      $select = array();
+      $select[] = '<optgroup label="Create New Revision">';
+      $select[] = '<option value="">Create a new Revision...</option>';
       $select[] = '</optgroup>';
-    }
 
-    $select =
-      '<select name="revisionID">'.
+      $revision_data = new DifferentialRevisionListData(
+        DifferentialRevisionListData::QUERY_OPEN_OWNED,
+        array($request->getUser()->getPHID()));
+      $revisions = $revision_data->loadRevisions();
+
+      if ($revisions) {
+        $select[] = '<optgroup label="Update Existing Revision">';
+        foreach ($revisions as $revision) {
+          $select[] = phutil_render_tag(
+            'option',
+            array(
+              'value' => $revision->getID(),
+            ),
+            phutil_escape_html($revision->getTitle()));
+        }
+        $select[] = '</optgroup>';
+      }
+
+      $select =
+        '<select name="revisionID">'.
         implode("\n", $select).
-      '</select>';
+        '</select>';
 
-    $action_form = new AphrontFormView();
-    $action_form
-      ->setUser($request->getUser())
-      ->setAction('/differential/revision/edit/')
-      ->addHiddenInput('diffID', $diff->getID())
-      ->addHiddenInput('viaDiffView', 1)
-      ->appendChild(
-        id(new AphrontFormMarkupControl())
+      $action_form = new AphrontFormView();
+      $action_form
+        ->setUser($request->getUser())
+        ->setAction('/differential/revision/edit/')
+        ->addHiddenInput('diffID', $diff->getID())
+        ->addHiddenInput('viaDiffView', 1)
+        ->appendChild(
+          id(new AphrontFormMarkupControl())
           ->setLabel('Attach To')
           ->setValue($select))
-      ->appendChild(
-        id(new AphrontFormSubmitControl())
+        ->appendChild(
+          id(new AphrontFormSubmitControl())
           ->setValue('Continue'));
 
-    $action_panel->appendChild($action_form);
+      $action_panel->appendChild($action_form);
+
+      $top_panel = $action_panel;
+    }
 
 
 
@@ -101,7 +115,7 @@ class DifferentialDiffViewController extends DifferentialController {
         implode(
           "\n",
           array(
-            $action_panel->render(),
+            $top_panel->render(),
             $table_of_contents->render(),
             $details->render(),
           )).

src/applications/differential/controller/diffview/__init__.php

@@ -12,6 +12,7 @@ phutil_require_module('phabricator', 'applications/differential/data/revisionlis
 phutil_require_module('phabricator', 'applications/differential/storage/diff');
 phutil_require_module('phabricator', 'applications/differential/view/changesetlistview');
 phutil_require_module('phabricator', 'applications/differential/view/difftableofcontents');
+phutil_require_module('phabricator', 'infrastructure/env');
 phutil_require_module('phabricator', 'view/form/base');
 phutil_require_module('phabricator', 'view/form/control/markup');
 phutil_require_module('phabricator', 'view/form/control/submit');