Bitbucket Server importer: Eliminate most idle-in-transaction issues

Just like with the GitHub importer, the Bitbucket Server importer can hit the
default 60 s idle-in-transaction timeouts if it takes too long to create the
merge request. We solve this by using the same approach as the GitHub importer:

1. Bypass all validation and hooks in creating a merge request
2. Insert the Git data in a separate transaction

Part of #50021

1 files changed, 40 insertions, 0 deletions

diff --git a/lib/gitlab/import/merge_request_creator.rb b/lib/gitlab/import/merge_request_creator.rb
new file mode 100644
index 00000000000..a01951b0762
--- /dev/null
+++ b/lib/gitlab/import/merge_request_creator.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+# This module is designed for importers that need to create many merge
+# requests quickly.  When creating merge requests there are a lot of hooks
+# that may run, for many different reasons. Many of these hooks (e.g. the ones
+# used for rendering Markdown) are completely unnecessary and may even lead to
+# transaction timeouts.
+#
+# To ensure importing merge requests requests has a minimal impact and can
+# complete in a reasonable time we bypass all the hooks by inserting the row
+# and then retrieving it. We then only perform the additional work that is
+# strictly necessary.
+module Gitlab
+  module Import
+    class MergeRequestCreator
+      include ::Gitlab::Import::DatabaseHelpers
+      include ::Gitlab::Import::MergeRequestHelpers
+
+      attr_accessor :project
+
+      def initialize(project)
+        @project = project
+      end
+
+      def execute(attributes)
+        source_branch_sha = attributes.delete(:source_branch_sha)
+        target_branch_sha = attributes.delete(:target_branch_sha)
+        iid = attributes[:iid]
+
+        merge_request, already_exists = create_merge_request_without_hooks(project, attributes, iid)
+
+        if merge_request
+          insert_or_replace_git_data(merge_request, source_branch_sha, target_branch_sha, already_exists)
+        end
+
+        merge_request
+      end
+    end
+  end
+end