Fix argument type for background migration

Follow up to https://gitlab.com/gitlab-org/gitlab/-/issues/277327 where
we got the argument type to `migrate_in` wrong (it uses splat instead of
a named argument).

changelogs/unreleased/277327-fix-background-migration-argument-type.yml

+---
+title: Fix argument type for background migration
+merge_request: 55097
+author:
+type: fixed

db/post_migrate/20210111075105_schedule_uuid_population_for_security_findings.rb

@@ -11,13 +11,7 @@ class ScheduleUuidPopulationForSecurityFindings < ActiveRecord::Migration[6.0]
   disable_ddl_transaction!
 
   def up
-    Gitlab::BackgroundMigration::PopulateUuidsForSecurityFindings.security_findings.each_batch(column: :scan_id, of: BATCH_SIZE) do |batch, index|
-      migrate_in(
-        DELAY_INTERVAL * index,
-        MIGRATION_CLASS,
-        batch.pluck(:scan_id)
-      )
-    end
+    # no-op, replaced by 20210111075206_schedule_uuid_population_for_security_findings2.rb
   end
 
   def down

db/post_migrate/20210111075206_schedule_uuid_population_for_security_findings2.rb

+# frozen_string_literal: true
+
+# This replaces the previous post-deployment migration 20210111075105_schedule_uuid_population_for_security_findings.rb,
+# we have to run this again due to a bug in how we were receiving the arguments in the background migration.
+class ScheduleUuidPopulationForSecurityFindings2 < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  MIGRATION_CLASS = 'PopulateUuidsForSecurityFindings'
+  DELAY_INTERVAL = 2.minutes
+  BATCH_SIZE = 25
+
+  disable_ddl_transaction!
+
+  def up
+    ::Gitlab::BackgroundMigration.steal(MIGRATION_CLASS) do |job|
+      job.delete
+
+      false
+    end
+
+    Gitlab::BackgroundMigration::PopulateUuidsForSecurityFindings.security_findings.each_batch(column: :scan_id, of: BATCH_SIZE) do |batch, index|
+      migrate_in(
+        DELAY_INTERVAL * index,
+        MIGRATION_CLASS,
+        batch.pluck(:scan_id)
+      )
+    end
+  end
+
+  def down
+    # no-op
+  end
+end

db/schema_migrations/20210111075206

+9da5955d9f71d671a41e6d03f76f87370d6e67b6853707adb164f7ffa8c75082
\ No newline at end of file

ee/lib/ee/gitlab/background_migration/populate_uuids_for_security_findings.rb

@@ -228,7 +228,7 @@ module EE
         end
 
         override :perform
-        def perform(scan_ids)
+        def perform(*scan_ids)
           SecurityScan.where(id: scan_ids).includes(:pipeline, :artifacts).each(&:recover_findings)
 
           log_info(scan_ids.count)

ee/spec/lib/ee/gitlab/background_migration/populate_uuids_for_security_findings_spec.rb

@@ -54,7 +54,7 @@ RSpec.describe ::Gitlab::BackgroundMigration::PopulateUuidsForSecurityFindings d
   end
 
   describe '#perform' do
-    subject(:populate_uuids) { described_class.new.perform([security_scan_1.id, security_scan_2.id, security_scan_3.id]) }
+    subject(:populate_uuids) { described_class.new.perform(security_scan_1.id, security_scan_2.id, security_scan_3.id) }
 
     it 'sets the `uuid` of findings' do
       expect { populate_uuids }.to change { finding_1.reload.uuid }.from(nil)

ee/spec/migrations/schedule_uuid_population_for_security_findings_spec.rb → ee/spec/migrations/schedule_uuid_population_for_security_findings2_spec.rb

@@ -3,7 +3,7 @@
 require 'spec_helper'
 require_migration!
 
-RSpec.describe ScheduleUuidPopulationForSecurityFindings do
+RSpec.describe ScheduleUuidPopulationForSecurityFindings2 do
   let(:namespaces) { table(:namespaces) }
   let(:projects) { table(:projects) }
   let(:ci_pipelines) { table(:ci_pipelines) }

lib/gitlab/background_migration/populate_uuids_for_security_findings.rb

@@ -10,7 +10,7 @@ module Gitlab
         NOP_RELATION.new
       end
 
-      def perform(_scan_ids); end
+      def perform(*_scan_ids); end
     end
   end
 end