Parse Conflicts field in commit message

Summary:
Git adds it automatically.

I don't like this solution much because there could be other unknown fields appended to the end of the commit message which will break parsing.

Test Plan:
Reparsed commit ending with:

> Differential Revision: ...
> Conflicts: ...

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4157

src/__phutil_library_map__.php

@@ -236,6 +236,7 @@ phutil_register_library_map(array(
     'DifferentialCommentPreviewController' => 'applications/differential/controller/DifferentialCommentPreviewController.php',
     'DifferentialCommentSaveController' => 'applications/differential/controller/DifferentialCommentSaveController.php',
     'DifferentialCommitsFieldSpecification' => 'applications/differential/field/specification/DifferentialCommitsFieldSpecification.php',
+    'DifferentialConflictsFieldSpecification' => 'applications/differential/field/specification/DifferentialConflictsFieldSpecification.php',
     'DifferentialController' => 'applications/differential/controller/DifferentialController.php',
     'DifferentialDAO' => 'applications/differential/storage/DifferentialDAO.php',
     'DifferentialDateCreatedFieldSpecification' => 'applications/differential/field/specification/DifferentialDateCreatedFieldSpecification.php',
@@ -1547,6 +1548,7 @@ phutil_register_library_map(array(
     'DifferentialCommentPreviewController' => 'DifferentialController',
     'DifferentialCommentSaveController' => 'DifferentialController',
     'DifferentialCommitsFieldSpecification' => 'DifferentialFieldSpecification',
+    'DifferentialConflictsFieldSpecification' => 'DifferentialFieldSpecification',
     'DifferentialController' => 'PhabricatorController',
     'DifferentialDAO' => 'PhabricatorLiskDAO',
     'DifferentialDateCreatedFieldSpecification' => 'DifferentialFieldSpecification',

src/applications/differential/field/selector/DifferentialDefaultFieldSelector.php

@@ -26,6 +26,7 @@ final class DifferentialDefaultFieldSelector
       new DifferentialApplyPatchFieldSpecification(),
       new DifferentialRevisionIDFieldSpecification(),
       new DifferentialGitSVNIDFieldSpecification(),
+      new DifferentialConflictsFieldSpecification(),
       new DifferentialDateModifiedFieldSpecification(),
       new DifferentialDateCreatedFieldSpecification(),
       new DifferentialAuditorsFieldSpecification(),

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

@@ -0,0 +1,34 @@
+<?php
+
+final class DifferentialConflictsFieldSpecification
+  extends DifferentialFieldSpecification {
+
+  public function shouldAppearOnCommitMessage() {
+    return true;
+  }
+
+  public function shouldAppearOnCommitMessageTemplate() {
+    return false;
+  }
+
+  public function getCommitMessageKey() {
+    return 'conflicts';
+  }
+
+  public function setValueFromParsedCommitMessage($value) {
+    return $this;
+  }
+
+  public function renderLabelForCommitMessage() {
+    return 'Conflicts';
+  }
+
+  public function renderValueForCommitMessage($is_edit) {
+    return null;
+  }
+
+  public function parseValueFromCommitMessage($value) {
+    return $value;
+  }
+
+}