Merge pull request #498 from gocardless/sorbet-compatible-queries

Sorbet compatible queries

README.md

@@ -611,6 +611,30 @@ describe "some callback" do
 end
 ```
 
+## Compatibility with type checkers
+
+Including ActiveRecordQueries to your model can cause issues with type checkers
+such as Sorbet, this is because this technically is using a dynamic include,
+which is not supported by Sorbet.
+
+To avoid these issues you can instead include the TypeSafeActiveRecordQueries
+module and pass in configuration.
+
+```ruby
+class Order < ActiveRecord::Base
+  has_many :order_transitions, autosave: false
+
+  include Statesman::Adapters::TypeSafeActiveRecordQueries
+
+  configure_state_machine transition_class: OrderTransition,
+                          initial_state: :pending
+
+  def state_machine
+    @state_machine ||= OrderStateMachine.new(self, transition_class: OrderTransition)
+  end
+end
+```
+
 # Third-party extensions
 
 [statesman-sequel](https://github.com/badosu/statesman-sequel) - An adapter to make Statesman work with [Sequel](https://github.com/jeremyevans/sequel)

lib/statesman.rb

@@ -14,6 +14,8 @@ module Adapters
              "statesman/adapters/active_record_transition"
     autoload :ActiveRecordQueries,
              "statesman/adapters/active_record_queries"
+    autoload :TypeSafeActiveRecordQueries,
+             "statesman/adapters/type_safe_active_record_queries"
   end
   require "statesman/railtie" if defined?(::Rails::Railtie)
 

lib/statesman/adapters/type_safe_active_record_queries.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Statesman
+  module Adapters
+    module TypeSafeActiveRecordQueries
+      def configure_state_machine(args = {})
+        transition_class = args.fetch(:transition_class)
+        initial_state = args.fetch(:initial_state)
+
+        include(
+          ActiveRecordQueries::ClassMethods.new(
+            transition_class: transition_class,
+            initial_state: initial_state,
+            most_recent_transition_alias: try(:most_recent_transition_alias),
+            transition_name: try(:transition_name),
+          ),
+        )
+      end
+    end
+  end
+end

spec/statesman/adapters/type_safe_active_record_queries_spec.rb

@@ -0,0 +1,208 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+describe Statesman::Adapters::TypeSafeActiveRecordQueries, active_record: true do
+  def configure(klass, transition_class)
+    klass.send(:extend, described_class)
+    klass.configure_state_machine(
+      transition_class: transition_class,
+      initial_state: :initial,
+    )
+  end
+
+  before do
+    prepare_model_table
+    prepare_transitions_table
+    prepare_other_model_table
+    prepare_other_transitions_table
+
+    Statesman.configure do
+      storage_adapter(Statesman::Adapters::ActiveRecord)
+    end
+  end
+
+  after { Statesman.configure { storage_adapter(Statesman::Adapters::Memory) } }
+
+  let!(:model) do
+    model = MyActiveRecordModel.create
+    model.state_machine.transition_to(:succeeded)
+    model
+  end
+
+  let!(:other_model) do
+    model = MyActiveRecordModel.create
+    model.state_machine.transition_to(:failed)
+    model
+  end
+
+  let!(:initial_state_model) { MyActiveRecordModel.create }
+
+  let!(:returned_to_initial_model) do
+    model = MyActiveRecordModel.create
+    model.state_machine.transition_to(:failed)
+    model.state_machine.transition_to(:initial)
+    model
+  end
+
+  shared_examples "testing methods" do
+    before do
+      configure(MyActiveRecordModel, MyActiveRecordModelTransition)
+      configure(OtherActiveRecordModel, OtherActiveRecordModelTransition)
+
+      MyActiveRecordModel.send(:has_one, :other_active_record_model)
+      OtherActiveRecordModel.send(:belongs_to, :my_active_record_model)
+    end
+
+    describe ".in_state" do
+      context "given a single state" do
+        subject { MyActiveRecordModel.in_state(:succeeded) }
+
+        it { is_expected.to include model }
+        it { is_expected.to_not include other_model }
+      end
+
+      context "given multiple states" do
+        subject { MyActiveRecordModel.in_state(:succeeded, :failed) }
+
+        it { is_expected.to include model }
+        it { is_expected.to include other_model }
+      end
+
+      context "given the initial state" do
+        subject { MyActiveRecordModel.in_state(:initial) }
+
+        it { is_expected.to include initial_state_model }
+        it { is_expected.to include returned_to_initial_model }
+      end
+
+      context "given an array of states" do
+        subject { MyActiveRecordModel.in_state(%i[succeeded failed]) }
+
+        it { is_expected.to include model }
+        it { is_expected.to include other_model }
+      end
+
+      context "merging two queries" do
+        subject do
+          MyActiveRecordModel.in_state(:succeeded).
+            joins(:other_active_record_model).
+            merge(OtherActiveRecordModel.in_state(:initial))
+        end
+
+        it { is_expected.to be_empty }
+      end
+    end
+
+    describe ".not_in_state" do
+      context "given a single state" do
+        subject { MyActiveRecordModel.not_in_state(:failed) }
+
+        it { is_expected.to include model }
+        it { is_expected.to_not include other_model }
+      end
+
+      context "given multiple states" do
+        subject(:not_in_state) { MyActiveRecordModel.not_in_state(:succeeded, :failed) }
+
+        it do
+          expect(not_in_state).to contain_exactly(initial_state_model,
+                                                  returned_to_initial_model)
+        end
+      end
+
+      context "given an array of states" do
+        subject(:not_in_state) { MyActiveRecordModel.not_in_state(%i[succeeded failed]) }
+
+        it do
+          expect(not_in_state).to contain_exactly(initial_state_model,
+                                                  returned_to_initial_model)
+        end
+      end
+    end
+
+    context "with a custom name for the transition association" do
+      before do
+        # Switch to using OtherActiveRecordModelTransition, so the existing
+        # relation with MyActiveRecordModelTransition doesn't interfere with
+        # this spec.
+        MyActiveRecordModel.send(:has_many,
+                                 :custom_name,
+                                 class_name: "OtherActiveRecordModelTransition")
+
+        MyActiveRecordModel.class_eval do
+          def self.transition_class
+            OtherActiveRecordModelTransition
+          end
+        end
+      end
+
+      describe ".in_state" do
+        subject(:query) { MyActiveRecordModel.in_state(:succeeded) }
+
+        specify { expect { query }.to_not raise_error }
+      end
+    end
+
+    context "with a custom primary key for the model" do
+      before do
+        # Switch to using OtherActiveRecordModelTransition, so the existing
+        # relation with MyActiveRecordModelTransition doesn't interfere with
+        # this spec.
+        # Configure the relationship to use a different primary key,
+        MyActiveRecordModel.send(:has_many,
+                                 :custom_name,
+                                 class_name: "OtherActiveRecordModelTransition",
+                                 primary_key: :external_id)
+
+        MyActiveRecordModel.class_eval do
+          def self.transition_class
+            OtherActiveRecordModelTransition
+          end
+        end
+      end
+
+      describe ".in_state" do
+        subject(:query) { MyActiveRecordModel.in_state(:succeeded) }
+
+        specify { expect { query }.to_not raise_error }
+      end
+    end
+
+    context "after_commit transactional integrity" do
+      before do
+        MyStateMachine.class_eval do
+          cattr_accessor(:after_commit_callback_executed) { false }
+
+          after_transition(from: :initial, to: :succeeded, after_commit: true) do
+            # This leaks state in a testable way if transactional integrity is broken.
+            MyStateMachine.after_commit_callback_executed = true
+          end
+        end
+      end
+
+      after do
+        MyStateMachine.class_eval do
+          callbacks[:after_commit] = []
+        end
+      end
+
+      let!(:model) do
+        MyActiveRecordModel.create
+      end
+
+      it do
+        expect do
+          ActiveRecord::Base.transaction do
+            model.state_machine.transition_to!(:succeeded)
+            raise ActiveRecord::Rollback
+          end
+        end.to_not change(MyStateMachine, :after_commit_callback_executed)
+      end
+    end
+  end
+
+  context "using configuration method" do
+    include_examples "testing methods"
+  end
+end