Merge branch 'fix-new-mr-502' into 'master'

Fix 502 error on new merge request page

When diff is huge we try to render it that cause 502 error often.
After this patch we apply soft limits to diffs. So if diff is huge - we doing show it

Fixes #1323

app/controllers/projects/merge_requests_controller.rb

@@ -90,6 +90,9 @@ class Projects::MergeRequestsController < Projects::ApplicationController
       @merge_request.title = @merge_request.source_branch.titleize.humanize
       @target_project = @merge_request.target_project
       @target_repo = @target_project.repository
+
+      diff_line_count = Commit::diff_line_count(@diffs)
+      @suppress_diff = Commit::diff_suppress?(@diffs, diff_line_count)
     end
   end

app/views/projects/commits/_diffs.html.haml

@@ -6,12 +6,13 @@
     %p
       To preserve performance the diff is not shown.
       - if current_controller?(:commit) or current_controller?(:merge_requests)
-        Please, download the diff as
         - if current_controller?(:commit)
+          Please, download the diff as
           = link_to "plain diff", project_commit_path(@project, @commit, format: :diff), class: "underlined-link"
           or
           = link_to "email patch", project_commit_path(@project, @commit, format: :patch), class: "underlined-link"
-        - else
+        - elsif @merge_request && @merge_request.persisted?
+          Please, download the diff as
           = link_to "plain diff", project_merge_request_path(@project, @merge_request, format: :diff), class: "underlined-link"
           or
           = link_to "email patch", project_merge_request_path(@project, @merge_request, format: :patch), class: "underlined-link"