Remove temporal fix for import/export

lib/gitlab/import_export/base_relation_factory.rb

@@ -43,12 +43,11 @@ module Gitlab
         relation_name.to_s.constantize
       end
 
-      def initialize(relation_sym:, relation_hash:, members_mapper:, object_builder:, merge_requests_mapping: nil, user:, importable:, excluded_keys: [])
+      def initialize(relation_sym:, relation_hash:, members_mapper:, object_builder:, user:, importable:, excluded_keys: [])
         @relation_name = self.class.overrides[relation_sym]&.to_sym || relation_sym
         @relation_hash = relation_hash.except('noteable_id')
         @members_mapper = members_mapper
         @object_builder = object_builder
-        @merge_requests_mapping = merge_requests_mapping
         @user = user
         @importable = importable
         @imported_object_retries = 0

lib/gitlab/import_export/project_relation_factory.rb

@@ -111,28 +111,6 @@ module Gitlab
         @relation_hash['group_id'] = @importable.namespace_id
       end
 
-      # This code is a workaround for broken project exports that don't
-      # export merge requests with CI pipelines (i.e. exports that were
-      # generated from
-      # https://gitlab.com/gitlab-org/gitlab/merge_requests/17844).
-      # This method can be removed in GitLab 12.6.
-      def update_merge_request_references
-        # If a merge request was properly created, we don't need to fix
-        # up this export.
-        return if @relation_hash['merge_request']
-
-        merge_request_id = @relation_hash['merge_request_id']
-
-        return unless merge_request_id
-
-        new_merge_request_id = @merge_requests_mapping[merge_request_id]
-
-        return unless new_merge_request_id
-
-        @relation_hash['merge_request_id'] = new_merge_request_id
-        parsed_relation_hash['merge_request_id'] = new_merge_request_id
-      end
-
       def setup_build
         @relation_hash.delete('trace') # old export files have trace
         @relation_hash.delete('token')
@@ -147,8 +125,6 @@ module Gitlab
       end
 
       def setup_pipeline
-        update_merge_request_references
-
         @relation_hash.fetch('stages', []).each do |stage|
           stage.statuses.each do |status|
             status.pipeline = imported_object

lib/gitlab/import_export/relation_tree_restorer.rb

@@ -76,8 +76,6 @@ module Gitlab
         import_failure_service.with_retry(action: 'relation_object.save!', relation_key: relation_key, relation_index: relation_index) do
           relation_object.save!
         end
-
-        save_id_mapping(relation_key, data_hash, relation_object)
       rescue => e
         import_failure_service.log_import_failure(
           source: 'process_relation_item!',
@@ -90,17 +88,6 @@ module Gitlab
         @import_failure_service ||= ImportFailureService.new(@importable)
       end
 
-      # Older, serialized CI pipeline exports may only have a
-      # merge_request_id and not the full hash of the merge request. To
-      # import these pipelines, we need to preserve the mapping between
-      # the old and new the merge request ID.
-      def save_id_mapping(relation_key, data_hash, relation_object)
-        return unless importable_class == Project
-        return unless relation_key == 'merge_requests'
-
-        merge_requests_mapping[data_hash['id']] = relation_object.id
-      end
-
       def relations
         @relations ||=
           @reader
@@ -219,13 +206,8 @@ module Gitlab
         importable_class.to_s.downcase.to_sym
       end
 
-      # A Hash of the imported merge request ID -> imported ID.
-      def merge_requests_mapping
-        @merge_requests_mapping ||= {}
-      end
-
       def relation_factory_params(relation_key, data_hash)
-        base_params = {
+        {
           relation_sym: relation_key.to_sym,
           relation_hash: data_hash,
           importable: @importable,
@@ -234,9 +216,6 @@ module Gitlab
           user: @user,
           excluded_keys: excluded_keys_for_relation(relation_key)
         }
-
-        base_params[:merge_requests_mapping] = merge_requests_mapping if importable_class == Project
-        base_params
       end
     end
   end

spec/lib/gitlab/import_export/base_relation_factory_spec.rb

@@ -7,7 +7,6 @@ describe Gitlab::ImportExport::BaseRelationFactory do
   let(:project) { create(:project) }
   let(:members_mapper) { double('members_mapper').as_null_object }
   let(:relation_sym) { :project_snippets }
-  let(:merge_requests_mapping) { {} }
   let(:relation_hash) { {} }
   let(:excluded_keys) { [] }
 
@@ -16,7 +15,6 @@ describe Gitlab::ImportExport::BaseRelationFactory do
                            relation_hash: relation_hash,
                            object_builder: Gitlab::ImportExport::GroupProjectObjectBuilder,
                            members_mapper: members_mapper,
-                           merge_requests_mapping: merge_requests_mapping,
                            user: user,
                            importable: project,
                            excluded_keys: excluded_keys)

spec/lib/gitlab/import_export/project_relation_factory_spec.rb

@@ -6,7 +6,6 @@ describe Gitlab::ImportExport::ProjectRelationFactory do
   let(:group)   { create(:group) }
   let(:project) { create(:project, :repository, group: group) }
   let(:members_mapper) { double('members_mapper').as_null_object }
-  let(:merge_requests_mapping) { {} }
   let(:user) { create(:admin) }
   let(:excluded_keys) { [] }
   let(:created_object) do
@@ -14,7 +13,6 @@ describe Gitlab::ImportExport::ProjectRelationFactory do
                            relation_hash: relation_hash,
                            object_builder: Gitlab::ImportExport::GroupProjectObjectBuilder,
                            members_mapper: members_mapper,
-                           merge_requests_mapping: merge_requests_mapping,
                            user: user,
                            importable: project,
                            excluded_keys: excluded_keys)