add support for using Arcanist with git's log.decorate setting enabled

Summary:
Arcanist fails to find git's 'commit <hash>' header when log.decorate is
set in one of git's config files. git adds the named refs that point to
the commit in parentheses following the hash. This changes the regex
used by arcanist to match git commit headers to optionally match the
branch names in parentheses following the hash.

Test Plan:
Run `git config --global log.decorate short` and check that `arc diff`
runs successfully.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Koolvin

Differential Revision: https://secure.phabricator.com/D2344

src/parser/diff/ArcanistDiffParser.php

@@ -215,7 +215,7 @@ final class ArcanistDiffParser {
         // This is an SVN property change, probably from "svn diff".
         '(?P<type>Property changes on): (?P<cur>.+)',
         // This is a git commit message, probably from "git show".
-        '(?P<type>commit) (?P<hash>[a-f0-9]+)',
+        '(?P<type>commit) (?P<hash>[a-f0-9]+)(?: \(.*\))?',
         // This is a git diff, probably from "git show" or "git diff".
         // Note that the filenames may appear quoted.
         '(?P<type>diff --git) '.

src/parser/diff/__tests__/ArcanistDiffParserTestCase.php

@@ -428,6 +428,7 @@ EOTEXT
         $this->assertEqual(1, count(reset($changes)->getHunks()));
         break;
       case 'git-commit.gitdiff':
+      case 'git-commit-logdecorate.gitdiff':
         $this->assertEqual(1, count($changes));
         $change = reset($changes);
         $this->assertEqual(

src/parser/diff/__tests__/data/git-commit-logdecorate.gitdiff

@@ -0,0 +1,31 @@
+commit 76e2f1339c298c748aa0b52030799ed202a6537b (HEAD, refs/heads/master)
+Author: ngao <ngao@2c7ba8d8-a2f7-0310-a573-de162e16dcc7>
+Date:   Wed Mar 3 20:39:39 2010 +0000
+
+    Deprecating UIActionButton (Part 1)
+
+    Summary: Replaces calls to UIActionButton with <ui:button>.  I tested most
+             of these calls, but there were some that I didn't know how to
+             reach, so if you are one of the owners of this code, please test
+             your feature in my sandbox: www.ngao.devrs013.facebook.com
+
+             @brosenthal, I removed some logic that was setting a disabled state
+             on a UIActionButton, which is actually a no-op.
+
+    Reviewed By: brosenthal
+
+    Other Commenters: sparker, egiovanola
+
+    Test Plan: www.ngao.devrs013.facebook.com
+
+               Explicitly tested:
+               * ads creation flow (add keyword)
+               * ads manager (conversion tracking)
+               * help center (create a discussion)
+               * new user wizard (next step button)
+
+    Revert: OK
+
+    DiffCamp Revision: 94064
+
+    git-svn-id: svn+ssh://tubbs/svnroot/tfb/trunk/www@223593 2c7ba8d8

src/repository/api/git/ArcanistGitAPI.php

@@ -281,11 +281,12 @@ final class ArcanistGitAPI extends ArcanistRepositoryAPI {
       return '';
     } else if ($relative == self::GIT_MAGIC_ROOT_COMMIT) {
       // First commit.
-      list($stdout) = $this->execxLocal('log --format=medium HEAD');
+      list($stdout) = $this->execxLocal(
+        'log --no-decorate --format=medium HEAD');
     } else {
       // 2..N commits.
       list($stdout) = $this->execxLocal(
-        'log --first-parent --format=medium %s..HEAD',
+        'log --no-decorate --first-parent --format=medium %s..HEAD',
         $this->getRelativeCommit());
     }
     return $stdout;