Fetch and map refs/pull to refs/merge-requests in the GH import

update MR diff

2 files changed, 11 insertions, 28 deletions

diff --git a/lib/github/import.rb b/lib/github/import.rb
index c0cd8382875..47ed9acadc4 100644
--- a/lib/github/import.rb
+++ b/lib/github/import.rb
@@ -56,7 +56,7 @@ module Github
       begin
         project.ensure_repository
         project.repository.add_remote('github', repo_url)
-        project.repository.set_remote_as_mirror('github')
+        project.repository.set_import_remote_as_mirror('github')
         project.repository.fetch_remote('github', forced: true)
       rescue Gitlab::Git::Repository::NoRepository, Gitlab::Shell::Error => e
         error(:project, repo_url, e.message)
@@ -140,7 +140,7 @@ module Github
         response.body.each do |raw|
           pull_request  = Github::Representation::PullRequest.new(raw, options.merge(project: project))
           merge_request = MergeRequest.find_or_initialize_by(iid: pull_request.iid, source_project_id: project.id)
-          next unless merge_request.new_record? && pull_request.valid?
+          next unless merge_request.new_record? && pull_request.valid? && merge_request.source_branch_head
 
           begin
             pull_request.restore_branches!
@@ -173,8 +173,6 @@ module Github
             fetch_comments(merge_request, :review_comment, review_comments_url, LegacyDiffNote)
           rescue => e
             error(:pull_request, pull_request.url, e.message)
-          ensure
-            pull_request.remove_restored_branches!
           end
         end
 
diff --git a/lib/github/representation/pull_request.rb b/lib/github/representation/pull_request.rb
index 55461097e8a..ec030ade38a 100644
--- a/lib/github/representation/pull_request.rb
+++ b/lib/github/representation/pull_request.rb
@@ -10,7 +10,9 @@ module Github
 
       def source_branch_name
         @source_branch_name ||=
-          if cross_project? || !source_branch_exists?
+          if opened? && project.repository.branch_exists?(source_branch.ref)
+            source_branch.ref
+          elsif cross_project? && opened?
             source_branch_name_prefixed
           else
             source_branch_ref
@@ -20,7 +22,7 @@ module Github
       def source_branch_exists?
         return @source_branch_exists if defined?(@source_branch_exists)
 
-        @source_branch_exists = !cross_project? && source_branch.exists?
+        @source_branch_exists = project.repository.branch_exists?(source_branch_name)
       end
 
       def target_project
@@ -55,13 +57,6 @@ module Github
         restore_target_branch!
       end
 
-      def remove_restored_branches!
-        return if opened?
-
-        remove_source_branch!
-        remove_target_branch!
-      end
-
       private
 
       def project
@@ -72,8 +67,12 @@ module Github
         @source_branch ||= Representation::Branch.new(raw['head'], repository: project.repository)
       end
 
+      def source_branch_ref
+        "refs/merge-requests/#{iid}/head"
+      end
+
       def source_branch_name_prefixed
-        "gh-#{target_branch_short_sha}/#{iid}/#{source_branch_user}/#{source_branch_ref}"
+        "gh-#{target_branch_short_sha}/#{iid}/#{source_branch_user}/#{source_branch.ref}"
       end
 
       def target_branch
@@ -101,20 +100,6 @@ module Github
 
         target_branch.restore!(target_branch_name)
       end
-
-      def remove_source_branch!
-        # We should remove the source/target branches only if they were
-        # restored. Otherwise, we'll remove branches like 'master' that
-        # target_branch_exists? returns true. In other words, we need
-        # to clean up only the restored branches that (source|target)_branch_exists?
-        # returns false for the first time it has been called, because of
-        # this that is important to memoize these values.
-        source_branch.remove!(source_branch_name) unless source_branch_exists?
-      end
-
-      def remove_target_branch!
-        target_branch.remove!(target_branch_name) unless target_branch_exists?
-      end
     end
   end
 end