MR: Handle broken diff ex. in case its too huge

app/models/merge_request.rb

@@ -3,6 +3,8 @@ require File.join(Rails.root, "app/models/commit")
 class MergeRequest < ActiveRecord::Base
   include Upvote
 
+  BROKEN_DIFF = "--broken-diff"
+
   UNCHECKED = 1
   CAN_BE_MERGED = 2
   CANNOT_BE_MERGED = 3
@@ -108,14 +110,25 @@ class MergeRequest < ActiveRecord::Base
   def reloaded_diffs
     if open? && unmerged_diffs.any?
       self.st_diffs = unmerged_diffs
-      save
+      self.save
     end
-    diffs
+
+  rescue Grit::Git::GitTimeout
+    self.st_diffs = [BROKEN_DIFF]
+    self.save
+  end
+
+  def broken_diffs?
+    diffs == [BROKEN_DIFF]
+  end
+
+  def valid_diffs?
+    !broken_diffs?
   end
 
   def unmerged_diffs
     commits = project.repo.commits_between(target_branch, source_branch).map {|c| Commit.new(c)}
-    diffs = project.repo.diff(commits.first.prev_commit.id, commits.last.id) rescue []
+    diffs = project.repo.diff(commits.first.prev_commit.id, commits.last.id)
   end
 
   def last_commit

app/views/layouts/_project_menu.html.haml

@@ -19,6 +19,7 @@
         Issues
         %span.count= @project.issues.opened.count
 
+  - if @project.repo_exists?
     - if @project.merge_requests_enabled
       %li{:class => tab_class(:merge_requests)}
         = link_to project_merge_requests_path(@project) do

app/views/merge_requests/show/_diffs.html.haml

@@ -1,3 +1,8 @@
-= render "commits/diffs", :diffs => @diffs
-- if @diffs.empty?
-  %p.cgray Nothing to merge
+- if @merge_request.valid_diffs?
+  = render "commits/diffs", :diffs => @diffs
+- elsif @merge_request.broken_diffs?
+  %h4.nothing_here_message 
+    Can't load diff.
+    You can #{link_to "download MR patch", raw_project_merge_request_path(@project, @merge_request), :class => "vlink"} instead.
+- else
+  %h4.nothing_here_message Nothing to merge