Prevent ForeignKeyConstraintViolation during migration

- Reproduced reported issue by enhancing the unit test.
- Fixed ForeignKeyConstraintViolation by re-ordering migration
  statements.

Fixes issue #3803.

Author: philippthun

db/migrations/20240115163000_add_delete_cascade_to_foreign_keys.rb

@@ -8,8 +8,8 @@
     ForeignKey.new(:build_labels, :fk_build_labels_resource_guid, :resource_guid, :builds, :guid),
     ForeignKey.new(:build_annotations, :fk_build_annotations_resource_guid, :resource_guid, :builds, :guid),
     ForeignKey.new(:kpack_lifecycle_data, :fk_kpack_lifecycle_build_guid, :build_guid, :builds, :guid),
-    ForeignKey.new(:buildpack_lifecycle_data, :fk_buildpack_lifecycle_build_guid, :build_guid, :builds, :guid, new_constraint: true),
     ForeignKey.new(:buildpack_lifecycle_buildpacks, :fk_blbuildpack_bldata_guid, :buildpack_lifecycle_data_guid, :buildpack_lifecycle_data, :guid),
+    ForeignKey.new(:buildpack_lifecycle_data, :fk_buildpack_lifecycle_build_guid, :build_guid, :builds, :guid, new_constraint: true),
     ForeignKey.new(:task_labels, :fk_task_labels_resource_guid, :resource_guid, :tasks, :guid),
     ForeignKey.new(:task_annotations, :fk_task_annotations_resource_guid, :resource_guid, :tasks, :guid),
     ForeignKey.new(:revision_labels, :fk_revision_labels_resource_guid, :resource_guid, :revisions, :guid),

spec/migrations/20240115163000_add_delete_cascade_to_foreign_keys_spec.rb

@@ -28,12 +28,16 @@
       it 'deleted orphaned buildpack_lifecycle_data entries but kept valid ones' do
         db[:builds].insert(guid: 'build_guid')
         db[:buildpack_lifecycle_data].insert(guid: 'bld_guid', build_guid: 'build_guid')
+        db[:buildpack_lifecycle_buildpacks].insert(guid: 'blb_guid', buildpack_lifecycle_data_guid: 'bld_guid')
         db[:buildpack_lifecycle_data].insert(guid: 'another_bld_guid', build_guid: 'not_exists')
+        db[:buildpack_lifecycle_buildpacks].insert(guid: 'another_blb_guid', buildpack_lifecycle_data_guid: 'another_bld_guid')
 
         Sequel::Migrator.run(db, migrations_path, target: current_migration_index, allow_missing_migration_files: true)
 
         expect(db[:buildpack_lifecycle_data].where(guid: 'bld_guid').count).to eq(1)
+        expect(db[:buildpack_lifecycle_buildpacks].where(guid: 'blb_guid').count).to eq(1)
         expect(db[:buildpack_lifecycle_data].where(guid: 'another_bld_guid').count).to eq(0)
+        expect(db[:buildpack_lifecycle_buildpacks].where(guid: 'another_blb_guid').count).to eq(0)
       end
     end
   end