Cleanup draft column data

In a prior, now reverted migration, we attempted to populate the draft
column based on the "draft" or "WIP" nature of the title, mirroring what
is used in `MergeRequest#draft?`. However, an error in the SQL regexp
caused us to grab an additional number of MRs and label them as "draft".

Changelog:other

db/post_migrate/20220315171027_add_tmp_index_to_support_leaky_regex_cleanup.rb

+# frozen_string_literal: true
+
+class AddTmpIndexToSupportLeakyRegexCleanup < Gitlab::Database::Migration[1.0]
+  INDEX_NAME = "tmp_index_merge_requests_draft_and_status_leaky_regex"
+  LEAKY_REGEXP_STR = "^\\[draft\\]|\\(draft\\)|draft:|draft|\\[WIP\\]|WIP:|WIP"
+  CORRECTED_REGEXP_STR = "^(\\[draft\\]|\\(draft\\)|draft:|draft|\\[WIP\\]|WIP:|WIP)"
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :merge_requests, :id,
+      where: "draft = true AND state_id = 1 AND ((title)::text ~* '#{LEAKY_REGEXP_STR}'::text) AND ((title)::text !~* '#{CORRECTED_REGEXP_STR}'::text)",
+      name: INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index_by_name :merge_requests, INDEX_NAME
+  end
+end

db/post_migrate/20220315171129_cleanup_draft_data_from_faulty_regex.rb

+# frozen_string_literal: true
+
+class CleanupDraftDataFromFaultyRegex < Gitlab::Database::Migration[1.0]
+  MIGRATION       = 'CleanupDraftDataFromFaultyRegex'
+  DELAY_INTERVAL  = 5.minutes
+  BATCH_SIZE      = 20
+
+  disable_ddl_transaction!
+
+  class MergeRequest < ActiveRecord::Base
+    LEAKY_REGEXP_STR     = "^\\[draft\\]|\\(draft\\)|draft:|draft|\\[WIP\\]|WIP:|WIP"
+    CORRECTED_REGEXP_STR = "^(\\[draft\\]|\\(draft\\)|draft:|draft|\\[WIP\\]|WIP:|WIP)"
+
+    self.table_name = 'merge_requests'
+
+    include ::EachBatch
+
+    def self.eligible
+      where(state_id: 1)
+        .where(draft: true)
+        .where("title ~* ?", LEAKY_REGEXP_STR)
+        .where("title !~* ?", CORRECTED_REGEXP_STR)
+    end
+  end
+
+  def up
+    return unless Gitlab.com?
+
+    queue_background_migration_jobs_by_range_at_intervals(
+      MergeRequest.eligible,
+      MIGRATION,
+      DELAY_INTERVAL,
+      batch_size: BATCH_SIZE,
+      track_jobs: true
+    )
+  end
+
+  def down
+    # noop
+    #
+  end
+end

db/schema_migrations/20220315171027

+4c329622299c76ca753381f1ccc0686714d07eeee8acfc834e576d5a5addaafc
\ No newline at end of file

db/schema_migrations/20220315171129

+7ca832e710026c0721ecdcd50b477073aeaf7cb795c50acd604897f85707b163
\ No newline at end of file

db/structure.sql

@@ -29617,6 +29617,8 @@ CREATE INDEX tmp_index_issues_on_issue_type_and_id ON issues USING btree (issue_
 
 CREATE INDEX tmp_index_members_on_state ON members USING btree (state) WHERE (state = 2);
 
+CREATE INDEX tmp_index_merge_requests_draft_and_status_leaky_regex ON merge_requests USING btree (id) WHERE ((draft = true) AND (state_id = 1) AND ((title)::text ~* '^\[draft\]|\(draft\)|draft:|draft|\[WIP\]|WIP:|WIP'::text) AND ((title)::text !~* '^(\[draft\]|\(draft\)|draft:|draft|\[WIP\]|WIP:|WIP)'::text));
+
 CREATE INDEX tmp_index_namespaces_empty_traversal_ids_with_child_namespaces ON namespaces USING btree (id) WHERE ((parent_id IS NOT NULL) AND (traversal_ids = '{}'::integer[]));
 
 CREATE INDEX tmp_index_namespaces_empty_traversal_ids_with_root_namespaces ON namespaces USING btree (id) WHERE ((parent_id IS NULL) AND (traversal_ids = '{}'::integer[]));

lib/gitlab/background_migration/cleanup_draft_data_from_faulty_regex.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # Cleanup draft column data inserted by a faulty regex
+    #
+    class CleanupDraftDataFromFaultyRegex
+      # Migration only version of MergeRequest table
+      ##
+      class MergeRequest < ActiveRecord::Base
+        LEAKY_REGEXP_STR     = "^\\[draft\\]|\\(draft\\)|draft:|draft|\\[WIP\\]|WIP:|WIP"
+        CORRECTED_REGEXP_STR = "^(\\[draft\\]|\\(draft\\)|draft:|draft|\\[WIP\\]|WIP:|WIP)"
+
+        include EachBatch
+
+        self.table_name = 'merge_requests'
+
+        def self.eligible
+          where(state_id: 1)
+            .where(draft: true)
+            .where("title ~* ?", LEAKY_REGEXP_STR)
+            .where("title !~* ?", CORRECTED_REGEXP_STR)
+        end
+      end
+
+      def perform(start_id, end_id)
+        eligible_mrs = MergeRequest.eligible.where(id: start_id..end_id).pluck(:id)
+
+        return if eligible_mrs.empty?
+
+        eligible_mrs.each_slice(10) do |slice|
+          MergeRequest.where(id: slice).update_all(draft: false)
+        end
+
+        mark_job_as_succeeded(start_id, end_id)
+      end
+
+      private
+
+      def mark_job_as_succeeded(*arguments)
+        Gitlab::Database::BackgroundMigrationJob.mark_all_as_succeeded(
+          'CleanupDraftDataFromFaultyRegex',
+          arguments
+        )
+      end
+    end
+  end
+end

spec/lib/gitlab/background_migration/cleanup_draft_data_from_faulty_regex_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::BackgroundMigration::CleanupDraftDataFromFaultyRegex do
+  let(:namespaces)     { table(:namespaces) }
+  let(:projects)       { table(:projects) }
+  let(:merge_requests) { table(:merge_requests) }
+
+  let(:group)   { namespaces.create!(name: 'gitlab', path: 'gitlab') }
+  let(:project) { projects.create!(namespace_id: group.id) }
+
+  let(:draft_prefixes) { ["[Draft]", "(Draft)", "Draft:", "Draft", "[WIP]", "WIP:", "WIP"] }
+
+  def create_merge_request(params)
+    common_params = {
+      target_project_id: project.id,
+      target_branch: 'feature1',
+      source_branch: 'master'
+    }
+
+    merge_requests.create!(common_params.merge(params))
+  end
+
+  context "mr.draft == true, and title matches the leaky regex and not the corrected regex" do
+    let(:mr_ids) { merge_requests.all.collect(&:id) }
+
+    before do
+      draft_prefixes.each do |prefix|
+        (1..4).each do |n|
+          create_merge_request(
+            title: "#{prefix} This is a title",
+            draft: true,
+            state_id: 1
+          )
+        end
+      end
+
+      create_merge_request(title: "This has draft in the title", draft: true, state_id: 1)
+    end
+
+    it "updates all open draft merge request's draft field to true" do
+      expect { subject.perform(mr_ids.first, mr_ids.last) }
+        .to change { MergeRequest.where(draft: true).count }
+        .by(-1)
+    end
+
+    it "marks successful slices as completed" do
+      expect(subject).to receive(:mark_job_as_succeeded).with(mr_ids.first, mr_ids.last)
+
+      subject.perform(mr_ids.first, mr_ids.last)
+    end
+  end
+end

spec/migrations/20220315171129_cleanup_draft_data_from_faulty_regex_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require_migration!
+
+RSpec.describe CleanupDraftDataFromFaultyRegex do
+  let(:merge_requests) { table(:merge_requests) }
+
+  let!(:namespace) { table(:namespaces).create!(name: 'namespace', path: 'namespace') }
+  let!(:project) { table(:projects).create!(namespace_id: namespace.id) }
+
+  let(:default_mr_values) do
+    {
+      target_project_id: project.id,
+      draft: true,
+      source_branch: 'master',
+      target_branch: 'feature'
+    }
+  end
+
+  let!(:known_good_1) { merge_requests.create!(default_mr_values.merge(title: "Draft: Test Title")) }
+  let!(:known_good_2) { merge_requests.create!(default_mr_values.merge(title: "WIP: Test Title")) }
+  let!(:known_bad_1) { merge_requests.create!(default_mr_values.merge(title: "Known bad title drafts")) }
+  let!(:known_bad_2) { merge_requests.create!(default_mr_values.merge(title: "Known bad title wip")) }
+
+  describe '#up' do
+    it 'schedules CleanupDraftDataFromFaultyRegex background jobs filtering for eligble MRs' do
+      stub_const("#{described_class}::BATCH_SIZE", 2)
+      allow(Gitlab).to receive(:com?).and_return(true)
+
+      freeze_time do
+        migrate!
+
+        expect(described_class::MIGRATION).to be_scheduled_delayed_migration(5.minutes, known_bad_1.id, known_bad_2.id)
+
+        expect(BackgroundMigrationWorker.jobs.size).to eq(1)
+      end
+    end
+  end
+end