Ignore and drop MergeRequest#assignee_idid-ignore-assignee-id

5 files changed, 19 insertions, 66 deletions

diff --git a/app/models/concerns/deprecated_assignee.rb b/app/models/concerns/deprecated_assignee.rb
index 7f12ce39c96..1128f87ea2c 100644
--- a/app/models/concerns/deprecated_assignee.rb
+++ b/app/models/concerns/deprecated_assignee.rb
@@ -7,16 +7,6 @@
 module DeprecatedAssignee
   extend ActiveSupport::Concern
 
-  def assignee_ids=(ids)
-    nullify_deprecated_assignee
-    super
-  end
-
-  def assignees=(users)
-    nullify_deprecated_assignee
-    super
-  end
-
   def assignee_id=(id)
     self.assignee_ids = Array(id)
   end
@@ -32,55 +22,4 @@ module DeprecatedAssignee
   def assignee_id
     assignee_ids.first
   end
-
-  def assignee_ids
-    if Gitlab::Database.read_only? && pending_assignees_population?
-      return Array(deprecated_assignee_id)
-    end
-
-    update_assignees_relation
-    super
-  end
-
-  def assignees
-    if Gitlab::Database.read_only? && pending_assignees_population?
-      return User.where(id: deprecated_assignee_id)
-    end
-
-    update_assignees_relation
-    super
-  end
-
-  private
-
-  # This will make the background migration process quicker (#26496) as it'll have less
-  # assignee_id rows to look through.
-  def nullify_deprecated_assignee
-    return unless persisted? && Gitlab::Database.read_only?
-
-    update_column(:assignee_id, nil)
-  end
-
-  # This code should be removed in the clean-up phase of the
-  # background migration (#59457).
-  def pending_assignees_population?
-    persisted? && deprecated_assignee_id && merge_request_assignees.empty?
-  end
-
-  # If there's an assignee_id and no relation, it means the background
-  # migration at #26496 didn't reach this merge request yet.
-  # This code should be removed in the clean-up phase of the
-  # background migration (#59457).
-  def update_assignees_relation
-    if pending_assignees_population?
-      transaction do
-        merge_request_assignees.create!(user_id: deprecated_assignee_id, merge_request_id: id)
-        update_column(:assignee_id, nil)
-      end
-    end
-  end
-
-  def deprecated_assignee_id
-    read_attribute(:assignee_id)
-  end
 end
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 8ade91933a4..113eeeefa5b 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -16,6 +16,9 @@ class MergeRequest < ApplicationRecord
   include ReactiveCaching
   include FromUnion
   include DeprecatedAssignee
+  include IgnorableColumn
+
+  ignore_column :assignee_id
 
   self.reactive_cache_key = ->(model) { [model.project.id, model.iid] }
   self.reactive_cache_refresh_interval = 10.minutes
diff --git a/app/models/user.rb b/app/models/user.rb
index b439d1c0c16..0e211276bfa 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -146,7 +146,7 @@ class User < ApplicationRecord
 
   has_many :issue_assignees
   has_many :assigned_issues, class_name: "Issue", through: :issue_assignees, source: :issue
-  has_many :assigned_merge_requests, dependent: :nullify, foreign_key: :assignee_id, class_name: "MergeRequest" # rubocop:disable Cop/ActiveRecordDependent
+  has_many :assigned_merge_requests, dependent: :destroy, class_name: "MergeRequestAssignee" # rubocop:disable Cop/ActiveRecordDependent
 
   has_many :custom_attributes, class_name: 'UserCustomAttribute'
   has_many :callouts, class_name: 'UserCallout'
diff --git a/db/post_migrate/20190730152006_remove_assignee_id_from_merge_requests.rb b/db/post_migrate/20190730152006_remove_assignee_id_from_merge_requests.rb
new file mode 100644
index 00000000000..f444f5623fe
--- /dev/null
+++ b/db/post_migrate/20190730152006_remove_assignee_id_from_merge_requests.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RemoveAssigneeIdFromMergeRequests < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def change
+    remove_reference :merge_requests, :assignee, index: true, foreign_key: { to_table: :users }
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index f6b7e22fe09..d2a40a4bac7 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2019_07_29_090456) do
+ActiveRecord::Schema.define(version: 2019_07_30_152006) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
@@ -1983,7 +1983,6 @@ ActiveRecord::Schema.define(version: 2019_07_29_090456) do
     t.string "source_branch", null: false
     t.integer "source_project_id"
     t.integer "author_id"
-    t.integer "assignee_id"
     t.string "title"
     t.datetime "created_at"
     t.datetime "updated_at"
@@ -2017,7 +2016,6 @@ ActiveRecord::Schema.define(version: 2019_07_29_090456) do
     t.integer "state_id", limit: 2
     t.integer "approvals_before_merge"
     t.string "rebase_jid"
-    t.index ["assignee_id"], name: "index_merge_requests_on_assignee_id"
     t.index ["author_id"], name: "index_merge_requests_on_author_id"
     t.index ["created_at"], name: "index_merge_requests_on_created_at"
     t.index ["description"], name: "index_merge_requests_on_description_trigram", opclass: :gin_trgm_ops, using: :gin
@@ -3808,7 +3806,6 @@ ActiveRecord::Schema.define(version: 2019_07_29_090456) do
   add_foreign_key "merge_requests", "milestones", name: "fk_6a5165a692", on_delete: :nullify
   add_foreign_key "merge_requests", "projects", column: "source_project_id", name: "fk_3308fe130c", on_delete: :nullify
   add_foreign_key "merge_requests", "projects", column: "target_project_id", name: "fk_a6963e8447", on_delete: :cascade
-  add_foreign_key "merge_requests", "users", column: "assignee_id", name: "fk_6149611a04", on_delete: :nullify
   add_foreign_key "merge_requests", "users", column: "author_id", name: "fk_e719a85f8a", on_delete: :nullify
   add_foreign_key "merge_requests", "users", column: "merge_user_id", name: "fk_ad525e1f87", on_delete: :nullify
   add_foreign_key "merge_requests", "users", column: "updated_by_id", name: "fk_641731faff", on_delete: :nullify