Merge branch 'sh-handle-null-bytes-in-merge-request-diffs' into 'master'

Fix error creating a merge request when diff includes a null byte

Closes #57710

See merge request gitlab-org/gitlab-ce!26190

(cherry picked from commit a885e2d0a63b25411995fce2057067348f1bad9b)

6552197e Fix error creating a merge request when diff includes a null byte

2 files changed, 35 insertions, 0 deletions

diff --git a/spec/models/merge_request_diff_spec.rb b/spec/models/merge_request_diff_spec.rb
index e530e0302f5..53f5307ea0b 100644
--- a/spec/models/merge_request_diff_spec.rb
+++ b/spec/models/merge_request_diff_spec.rb
@@ -1,6 +1,8 @@
 require 'spec_helper'
 
 describe MergeRequestDiff do
+  include RepoHelpers
+
   let(:diff_with_commits) { create(:merge_request).merge_request_diff }
 
   describe 'validations' do
@@ -194,6 +196,25 @@ describe MergeRequestDiff do
         expect(diff_file).to be_binary
         expect(diff_file.diff).to eq(mr_diff.compare.diffs(paths: [path]).to_a.first.diff)
       end
+
+      context 'with diffs that contain a null byte' do
+        let(:filename) { 'test-null.txt' }
+        let(:content) { "a" * 10000 + "\x00" }
+        let(:project) { create(:project, :repository) }
+        let(:branch) { 'null-data' }
+        let(:target_branch) { 'master' }
+
+        it 'saves diffs correctly' do
+          create_file_in_repo(project, target_branch, branch, filename, content)
+
+          mr_diff = create(:merge_request, target_project: project, source_project: project, source_branch: branch, target_branch: target_branch).merge_request_diff
+          diff_file = mr_diff.merge_request_diff_files.find_by(new_path: filename)
+
+          expect(diff_file).to be_binary
+          expect(diff_file.diff).to eq(mr_diff.compare.diffs(paths: [filename]).to_a.first.diff)
+          expect(diff_file.diff).to include(content)
+        end
+      end
     end
   end
 
diff --git a/spec/support/helpers/repo_helpers.rb b/spec/support/helpers/repo_helpers.rb
index 3c6956cf5e0..4af90f4af79 100644
--- a/spec/support/helpers/repo_helpers.rb
+++ b/spec/support/helpers/repo_helpers.rb
@@ -115,4 +115,18 @@ eos
       commits: commits
     )
   end
+
+  def create_file_in_repo(
+        project, start_branch, branch_name, filename, content,
+        commit_message: 'Add new content')
+    Files::CreateService.new(
+      project,
+      project.owner,
+      commit_message: commit_message,
+      start_branch: start_branch,
+      branch_name: branch_name,
+      file_path: filename,
+      file_content: content
+    ).execute
+  end
 end