Fix Error 500 when creating a merge request that contains an image that was deleted and addedstanhu/gitlab-ce-fix-error-500-with-mr-images

Steps to reproduce:

1. Start with a repo with an image
2. Add a commit to delete the image
3. Add another commit to replace the image with another image

In a diff comparison, we really just compare about what the image was before the diff, not
the direct parent of the last commit. This MR fixes that.

Closes #3893, gitlab-org/gitlab-ee#678

Signed-off-by: Rémy Coutable <remy@rymai.me>

1 files changed, 10 insertions, 0 deletions

diff --git a/spec/features/merge_requests/create_new_mr_spec.rb b/spec/features/merge_requests/create_new_mr_spec.rb
index c68e1ea4af9..584574cc91a 100644
--- a/spec/features/merge_requests/create_new_mr_spec.rb
+++ b/spec/features/merge_requests/create_new_mr_spec.rb
@@ -67,4 +67,14 @@ feature 'Create New Merge Request', feature: true, js: true do
     expect(page).to have_content('Source branch "non-exist-source" does not exist')
     expect(page).to have_content('Target branch "non-exist-target" does not exist')
   end
+
+  context 'when a branch contains commits that both delete and add the same image' do
+    it 'renders the diff successfully' do
+      visit new_namespace_project_merge_request_path(project.namespace, project, merge_request: { target_branch: 'master', source_branch: 'deleted-image-test' })
+
+      click_link "Changes"
+
+      expect(page).to have_content "6049019_460s.jpg"
+    end
+  end
 end