fix MR source project assignment

CHANGELOG

@@ -82,6 +82,7 @@ v 8.11.0 (unreleased)
   - Adds support for pending invitation project members importing projects
   - Update devise initializer to turn on changed password notification emails. !5648 (tombell)
   - Avoid to show the original password field when password is automatically set. !5712 (duduribeiro)
+  - Fix importing GitLab projects with an invalid MR source project
 v 8.10.5 (unreleased)

lib/gitlab/import_export/relation_factory.rb

@@ -102,17 +102,19 @@ module Gitlab
       def update_project_references
         project_id = @relation_hash.delete('project_id')
+        # If source and target are the same, populate them with the new project ID.
+        if @relation_hash['source_project_id']
+          @relation_hash['source_project_id'] = same_source_and_target? ? project_id : -1
+        end
+
         # project_id may not be part of the export, but we always need to populate it if required.
         @relation_hash['project_id'] = project_id
         @relation_hash['gl_project_id'] = project_id if @relation_hash['gl_project_id']
         @relation_hash['target_project_id'] = project_id if @relation_hash['target_project_id']
-        @relation_hash['source_project_id'] = -1 if @relation_hash['source_project_id']
-        # If source and target are the same, populate them with the new project ID.
-        if @relation_hash['source_project_id'] && @relation_hash['target_project_id'] &&
-          @relation_hash['target_project_id'] == @relation_hash['source_project_id']
-          @relation_hash['source_project_id'] = project_id
-        end
+      end
+      def same_source_and_target?
+        @relation_hash['target_project_id'] && @relation_hash['target_project_id'] == @relation_hash['source_project_id']
       end
       def reset_ci_tokens

spec/lib/gitlab/import_export/project.json

@@ -2393,7 +2393,7 @@
       "source_project_id": 5,
       "author_id": 1,
       "assignee_id": null,
-      "title": "Cannot be automatically merged",
+      "title": "MR1",
       "created_at": "2016-06-14T15:02:36.568Z",
       "updated_at": "2016-06-14T15:02:56.815Z",
       "state": "opened",
@@ -2827,10 +2827,10 @@
       "id": 26,
       "target_branch": "master",
       "source_branch": "feature",
-      "source_project_id": 5,
+      "source_project_id": 4,
       "author_id": 1,
       "assignee_id": null,
-      "title": "Can be automatically merged",
+      "title": "MR2",
       "created_at": "2016-06-14T15:02:36.418Z",
       "updated_at": "2016-06-14T15:02:57.013Z",
       "state": "opened",

spec/lib/gitlab/import_export/project_tree_restorer_spec.rb

@@ -71,6 +71,28 @@ describe Gitlab::ImportExport::ProjectTreeRestorer, services: true do
         expect(Milestone.find_by_description('test milestone').issues).not_to be_empty
       end
+
+      context 'Merge requests' do
+        before do
+          restored_project_json
+        end
+
+        it 'always has the new project as a target' do
+          expect(MergeRequest.find_by_title('MR1').target_project).to eq(project)
+        end
+
+        it 'has the same source project as originally if source/target are the same' do
+          expect(MergeRequest.find_by_title('MR1').source_project).to eq(project)
+        end
+
+        it 'has the new project as target if source/target differ' do
+          expect(MergeRequest.find_by_title('MR2').target_project).to eq(project)
+        end
+
+        it 'has no source if source/target differ' do
+          expect(MergeRequest.find_by_title('MR2').source_project_id).to eq(-1)
+        end
+      end
     end
   end
 end