Remove orphaned builds without project / pipeline reference

db/migrate/20180420010016_add_pipeline_build_foreign_key.rb

@@ -6,13 +6,16 @@ class AddPipelineBuildForeignKey < ActiveRecord::Migration
   disable_ddl_transaction!
 
   def up
+    execute <<~SQL
+      DELETE FROM ci_builds WHERE project_id IS NULL OR commit_id IS NULL
+    SQL
+
     execute <<~SQL
       DELETE FROM ci_builds WHERE NOT EXISTS
         (SELECT true FROM ci_pipelines WHERE ci_pipelines.id = ci_builds.commit_id)
+        AND commit_id IS NOT NULL
     SQL
 
-    return if foreign_key_exists?(:ci_builds, :ci_pipelines, column: :commit_id)
-
     add_concurrent_foreign_key(:ci_builds, :ci_pipelines, column: :commit_id)
   end
 

spec/migrations/add_pipeline_build_foreign_key_spec.rb

@@ -16,10 +16,12 @@ describe AddPipelineBuildForeignKey, :migration do
     builds.create!(id: 102, commit_id: 222, project_id: 11)
     builds.create!(id: 103, commit_id: 333, project_id: 11)
     builds.create!(id: 104, commit_id: 12, project_id: 11)
+    builds.create!(id: 106, commit_id: nil, project_id: 11)
+    builds.create!(id: 107, commit_id: 12, project_id: nil)
   end
 
   it 'adds foreign key after removing orphans' do
-    expect(builds.all.count).to eq 4
+    expect(builds.all.count).to eq 6
     expect(foreign_key_exists?(:ci_builds, :ci_pipelines, column: :commit_id)).to be_falsey
 
     migrate!