Use MergeRequestDiff::COMMITS_SAFE_SIZE for Compare diff limit.

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/projects/compare_controller.rb

@@ -8,7 +8,7 @@ class Projects::CompareController < Projects::ApplicationController
   end
 
   def show
-    compare = Gitlab::Git::Compare.new(@repository.raw_repository, params[:from], params[:to])
+    compare = Gitlab::Git::Compare.new(@repository.raw_repository, params[:from], params[:to], MergeRequestDiff::COMMITS_SAFE_SIZE)
 
     @commits       = compare.commits
     @commit        = compare.commit

app/views/projects/compare/_form.html.haml

@@ -14,7 +14,7 @@
      
     = submit_tag "Compare", class: "btn btn-create commits-compare-btn"
     - if compare_to_mr_button?
-      = link_to compare_mr_path, class: 'prepend-left-10' do
+      = link_to compare_mr_path, class: 'prepend-left-10 btn' do
         %strong Make a merge request
 
 

app/views/projects/compare/show.html.haml

@@ -5,12 +5,6 @@
 
 = render "form"
 
-- if @commits.size > 100
-  .alert.alert-warning
-    %p
-      %strong Warning! This comparison includes more than 100 commits.
-    %p To preserve performance the line diff is not shown.
-
 - if @commits.present?
   %div.ui-box
     .title
@@ -24,9 +18,15 @@
     - else
       %ul.well-list= render Commit.decorate(@commits), project: @project
 
-  - unless @diffs.empty?
-    %h4 Diff
+  %h4 Diff
+  - if @diffs.present?
     = render "projects/commits/diffs", diffs: @diffs, project: @project
+  - elsif @commits.size > MergeRequestDiff::COMMITS_SAFE_SIZE
+    .alert.alert-warning
+      %p
+        %strong Warning! This comparison includes more than #{MergeRequestDiff::COMMITS_SAFE_SIZE} commits.
+      %p To preserve performance the line diff is not shown.
+
 - else
   .light-well
     %center