Parse VCS revert langauge in commit messages

Summary:
Ref T1751. When commit messages include language like "reverts X", parse it. This change doesn't do anything with the commits yet.

I attempted to cover all "natural" VCS messages and all reasonable human variations of these messages.

Test Plan: Added unit tests. Added `var_dump()` and used `scripts/repository/reparse.php --message X` to reparse some commit messages, with expected results.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T1751

Differential Revision: https://secure.phabricator.com/D5840

src/__phutil_library_map__.php

@@ -334,6 +334,7 @@ phutil_register_library_map(array(
     'DifferentialFieldSpecificationIncompleteException' => 'applications/differential/field/exception/DifferentialFieldSpecificationIncompleteException.php',
     'DifferentialFieldValidationException' => 'applications/differential/field/exception/DifferentialFieldValidationException.php',
     'DifferentialFreeformFieldSpecification' => 'applications/differential/field/specification/DifferentialFreeformFieldSpecification.php',
+    'DifferentialFreeformFieldTestCase' => 'applications/differential/field/specification/__tests__/DifferentialFreeformFieldTestCase.php',
     'DifferentialGitSVNIDFieldSpecification' => 'applications/differential/field/specification/DifferentialGitSVNIDFieldSpecification.php',
     'DifferentialHostFieldSpecification' => 'applications/differential/field/specification/DifferentialHostFieldSpecification.php',
     'DifferentialHovercardEventListener' => 'applications/differential/events/DifferentialHovercardEventListener.php',
@@ -1221,6 +1222,7 @@ phutil_register_library_map(array(
     'PhabricatorPhabricatorOAuthConfigOptions' => 'applications/config/option/PhabricatorPhabricatorOAuthConfigOptions.php',
     'PhabricatorPhameConfigOptions' => 'applications/phame/config/PhabricatorPhameConfigOptions.php',
     'PhabricatorPholioConfigOptions' => 'applications/pholio/config/PhabricatorPholioConfigOptions.php',
+    'PhabricatorPholioMockTestDataGenerator' => 'applications/pholio/lipsum/PhabricatorPholioMockTestDataGenerator.php',
     'PhabricatorPhortuneConfigOptions' => 'applications/phortune/option/PhabricatorPhortuneConfigOptions.php',
     'PhabricatorPhrequentConfigOptions' => 'applications/phrequent/config/PhabricatorPhrequentConfigOptions.php',
     'PhabricatorPhrictionConfigOptions' => 'applications/phriction/config/PhabricatorPhrictionConfigOptions.php',
@@ -2099,6 +2101,7 @@ phutil_register_library_map(array(
     'DifferentialFieldSpecificationIncompleteException' => 'Exception',
     'DifferentialFieldValidationException' => 'Exception',
     'DifferentialFreeformFieldSpecification' => 'DifferentialFieldSpecification',
+    'DifferentialFreeformFieldTestCase' => 'PhabricatorTestCase',
     'DifferentialGitSVNIDFieldSpecification' => 'DifferentialFieldSpecification',
     'DifferentialHostFieldSpecification' => 'DifferentialFieldSpecification',
     'DifferentialHovercardEventListener' => 'PhutilEventListener',
@@ -2935,6 +2938,7 @@ phutil_register_library_map(array(
     'PhabricatorPhabricatorOAuthConfigOptions' => 'PhabricatorApplicationConfigOptions',
     'PhabricatorPhameConfigOptions' => 'PhabricatorApplicationConfigOptions',
     'PhabricatorPholioConfigOptions' => 'PhabricatorApplicationConfigOptions',
+    'PhabricatorPholioMockTestDataGenerator' => 'PhabricatorTestDataGenerator',
     'PhabricatorPhortuneConfigOptions' => 'PhabricatorApplicationConfigOptions',
     'PhabricatorPhrequentConfigOptions' => 'PhabricatorApplicationConfigOptions',
     'PhabricatorPhrictionConfigOptions' => 'PhabricatorApplicationConfigOptions',

src/applications/differential/field/specification/DifferentialFreeformFieldSpecification.php

@@ -98,6 +98,53 @@ abstract class DifferentialFreeformFieldSpecification
     return $dependents;
   }
 
+  public static function findRevertedCommits($message) {
+    $reverts = array();
+    $matches = null;
+
+    // NOTE: Git language is "This reverts commit X."
+    // NOTE: Mercurial language is "Backed out changeset Y".
+
+    $prefixes = array(
+      'revert'        => true,
+      'reverts'       => true,
+      'back\s*out'    => true,
+      'backs\s*out'   => true,
+      'backed\s*out'  => true,
+      'undo'          => true,
+      'undoes'        => true,
+    );
+
+    $optional = array(
+      'commit'        => true,
+      'changeset'     => true,
+      'rev'           => true,
+      'revision'      => true,
+      'change'        => true,
+      'diff'          => true,
+    );
+
+    $pre_re = implode('|', array_keys($prefixes));
+    $opt_re = implode('|', array_keys($optional));
+
+    $matches = null;
+    preg_match_all(
+      '/\b(?i:'.$pre_re.')(?:\s+(?i:'.$opt_re.'))?([rA-Z0-9a-f,\s]+)\b/',
+      $message,
+      $matches);
+
+    $result = array();
+    foreach ($matches[1] as $commits) {
+      $commits = preg_split('/[,\s]+/', $commits);
+      $commits = array_filter($commits);
+      foreach ($commits as $commit) {
+        $result[$commit] = $commit;
+      }
+    }
+
+    return $result;
+  }
+
   public function didWriteRevision(DifferentialRevisionEditor $editor) {
     $message = $this->renderValueForCommitMessage(false);
 
@@ -151,6 +198,10 @@ abstract class DifferentialFreeformFieldSpecification
     PhabricatorRepositoryCommit $commit,
     PhabricatorRepositoryCommitData $data) {
 
+    $message = $this->renderValueForCommitMessage($is_edit = false);
+
+    $commits = self::findRevertedCommits($message);
+
     $user = id(new PhabricatorUser())->loadOneWhere(
       'phid = %s',
       $data->getCommitDetail('authorPHID'));
@@ -158,7 +209,6 @@ abstract class DifferentialFreeformFieldSpecification
       return;
     }
 
-    $message = $this->renderValueForCommitMessage($is_edit = false);
     $tasks_statuses = $this->findMentionedTasks($message);
     if (!$tasks_statuses) {
       return;

src/applications/differential/field/specification/__tests__/DifferentialFreeformFieldTestCase.php

@@ -0,0 +1,31 @@
+<?php
+
+final class DifferentialFreeformFieldTestCase extends PhabricatorTestCase {
+
+  public function testRevertedCommitParser() {
+    $map = array(
+      "Reverts 123" => array('123'),
+      "Reverts r123" => array('r123'),
+      "Reverts ac382f2" => array('ac382f2'),
+      "Reverts r22, r23" => array('r22', 'r23'),
+      "Reverts D99" => array('D99'),
+      "Backs out commit\n99\n100" => array('99', '100'),
+      "undo change f9f9f8f8" => array('f9f9f8f8'),
+      "Backedout Changeset rX1234" => array('rX1234'),
+      "This doesn't revert anything" => array(),
+      'nonrevert of r11' => array(),
+      "fixed a bug" => array(),
+    );
+
+    foreach ($map as $input => $expect) {
+      $actual = array_values(
+        DifferentialFreeformFieldSpecification::findRevertedCommits($input));
+
+      $this->assertEqual(
+        $expect,
+        $actual,
+        "Reverted commits in: {$input}");
+    }
+  }
+
+}