From 763a049f74990655982eb781b60577769f8f0b12 Mon Sep 17 00:00:00 2001
From: epriestley <git@epriestley.com>
Date: Mon, 24 Feb 2014 14:39:44 -0800
Subject: [PATCH] Possibly fix issue where refs engine finds empty refs?

Summary:
@mbishopim3 reported an issue in IRC:

> mbishopim3: epriestley: "Error updating working copy: Commit "" has not been discovered yet! Run discovery before updating refs." any ideas?

I can't reproduce it and it went away for him, but one theory is that we're getting here and git/hg are spitting out nothing, which we incorrectly parse as `array("")` when we intend `array()`.

Test Plan:
Pushed some new commits, ran `bin/repositoy refs X`, got expected results.

I can't actually reproduce the bug, but this might fix it and appears to make the code more correct.

Reviewers: btrahan

Reviewed By: btrahan

CC: mbishopim3, aran

Differential Revision: https://secure.phabricator.com/D8326
---
 .../engine/PhabricatorRepositoryRefEngine.php          | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/applications/repository/engine/PhabricatorRepositoryRefEngine.php b/src/applications/repository/engine/PhabricatorRepositoryRefEngine.php
index 41092c1030..56826186a1 100644
--- a/src/applications/repository/engine/PhabricatorRepositoryRefEngine.php
+++ b/src/applications/repository/engine/PhabricatorRepositoryRefEngine.php
@@ -247,6 +247,11 @@ final class PhabricatorRepositoryRefEngine
             '{node}\n',
             hgsprintf('%s', $new_head));
         }
+
+        $stdout = trim($stdout);
+        if (!strlen($stdout)) {
+          return array();
+        }
         return phutil_split_lines($stdout, $retain_newlines = false);
       case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
         if ($all_closing_heads) {
@@ -261,6 +266,11 @@ final class PhabricatorRepositoryRefEngine
             '%H',
             $new_head);
         }
+
+        $stdout = trim($stdout);
+        if (!strlen($stdout)) {
+          return array();
+        }
         return phutil_split_lines($stdout, $retain_newlines = false);
       default:
         throw new Exception(pht('Unsupported VCS "%s"!', $vcs));