Merge branch 'more_descriptive_git_shell_messages' into 'master'

Handle custom Git hook result in GitLab UI

## What does this MR do?

This MR fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/19190
It allows to show messages from git custom hooks

## Screenshots (if relevant)

![joxi_screenshot_1467651998090](/uploads/7f814523c96712c07b4f4b52c843aab3/joxi_screenshot_1467651998090.png)

See merge request !5073

1 files changed, 7 insertions, 2 deletions

diff --git a/lib/gitlab/git/hook.rb b/lib/gitlab/git/hook.rb
index 5415f4844d3..420c6883c45 100644
--- a/lib/gitlab/git/hook.rb
+++ b/lib/gitlab/git/hook.rb
@@ -41,7 +41,7 @@ module Gitlab
           chdir: repo_path
         }
 
-        Open3.popen3(vars, path, options) do |stdin, _, stderr, wait_thr|
+        Open3.popen3(vars, path, options) do |stdin, stdout, stderr, wait_thr|
           exit_status = true
           stdin.sync = true
 
@@ -60,7 +60,7 @@ module Gitlab
 
           unless wait_thr.value == 0
             exit_status = false
-            exit_message = stderr.gets
+            exit_message = retrieve_error_message(stderr, stdout)
           end
         end
 
@@ -76,6 +76,11 @@ module Gitlab
 
         [status, nil]
       end
+
+      def retrieve_error_message(stderr, stdout)
+        err_message = stderr.gets
+        err_message.blank? ? stdout.gets : err_message
+      end
     end
   end
 end