Exclude stubbed classes from subclasses after teardown

lib/rspec/mocks.rb

@@ -113,10 +113,11 @@ class << self
 
     # To speed up boot time a bit, delay loading optional or rarely
     # used features until their first use.
-    autoload :AnyInstance,      "rspec/mocks/any_instance"
-    autoload :ExpectChain,      "rspec/mocks/message_chain"
-    autoload :StubChain,        "rspec/mocks/message_chain"
-    autoload :MarshalExtension, "rspec/mocks/marshal_extension"
+    autoload :AnyInstance,                          "rspec/mocks/any_instance"
+    autoload :ExpectChain,                          "rspec/mocks/message_chain"
+    autoload :StubChain,                            "rspec/mocks/message_chain"
+    autoload :MarshalExtension,                     "rspec/mocks/marshal_extension"
+    autoload :ExcludeStubbedClassesFromSubclasses,  "rspec/mocks/exclude_stubbed_classes_from_subclasses"
 
     # Namespace for mock-related matchers.
     module Matchers

lib/rspec/mocks/configuration.rb

@@ -10,6 +10,7 @@ def initialize
         @verify_partial_doubles = false
         @temporarily_suppress_partial_double_verification = false
         @color = false
+        @exclude_stubbed_classes_from_subclasses = false
       end
 
       # Sets whether RSpec will warn, ignore, or fail a test when
@@ -178,6 +179,22 @@ def color?
         end
       end
 
+      def exclude_stubbed_classes_from_subclasses?
+        @exclude_stubbed_classes_from_subclasses
+      end
+
+      # When this is set to true, stubbed classes are excluded from the list of
+      # subclasses of the parent class after each spec.
+      def exclude_stubbed_classes_from_subclasses=(val)
+        @exclude_stubbed_classes_from_subclasses = !!val
+
+        if val
+          RSpec::Mocks::ExcludeStubbedClassesFromSubclasses.enable!
+        else
+          RSpec::Mocks::ExcludeStubbedClassesFromSubclasses.disable!
+        end
+      end
+
       # Monkey-patch `Marshal.dump` to enable dumping of mocked or stubbed
       # objects. By default this will not work since RSpec mocks works by
       # adding singleton methods that cannot be serialized. This patch removes

lib/rspec/mocks/exclude_stubbed_classes_from_subclasses.rb

@@ -0,0 +1,50 @@
+module RSpec
+  module Mocks
+    # Support for `exclude_stubbed_classes_from_subclasses` configuration.
+    #
+    # @private
+    class ExcludeStubbedClassesFromSubclasses
+      def self.enable!
+        return if Class.respond_to?(:subclasses_with_rspec_mocks)
+
+        require 'weakref'
+
+        mod_something = Module.new do
+          def excluded_subclasses
+            @excluded_subclasses ||= []
+            @excluded_subclasses.select(&:weakref_alive?).map do |ref|
+              ref.__getobj__
+            rescue RefError
+              nil
+            end.compact
+          end
+
+          def exclude_subclass(constant)
+            @excluded_subclasses ||= []
+            @excluded_subclasses << WeakRef.new(constant)
+          end
+        end
+        RSpec::Mocks.extend(mod_something)
+
+        Class.class_eval do
+          def subclasses_with_rspec_mocks
+            subclasses_without_rspec_mocks - RSpec::Mocks.excluded_subclasses
+          end
+
+          alias subclasses_without_rspec_mocks subclasses
+          alias subclasses subclasses_with_rspec_mocks
+        end
+      end
+
+      def self.disable!
+        return unless Class.respond_to?(:subclasses_with_rspec_mocks)
+
+        Class.class_eval do
+          undef subclasses_with_rspec_mocks
+          alias subclasses subclasses_without_rspec_mocks
+          undef subclasses_without_rspec_mocks
+        end
+      end
+    end
+  end
+end

lib/rspec/mocks/mutate_const.rb

@@ -221,6 +221,7 @@ def to_constant
         end
 
         def reset
+          RSpec::Mocks.exclude_subclass(@mutated_value) if RSpec::Mocks.configuration.exclude_stubbed_classes_from_subclasses?
           @constants_to_transfer.each do |const|
             @mutated_value.__send__(:remove_const, const)
           end
@@ -297,6 +298,7 @@ def to_constant
         end
 
         def reset
+          RSpec::Mocks.exclude_subclass(@mutated_value) if RSpec::Mocks.configuration.exclude_stubbed_classes_from_subclasses?
           @parent.__send__(:remove_const, @const_name)
         end
 

spec/rspec/mocks/exclude_stubbed_classes_from_subclasses_spec.rb

@@ -0,0 +1,66 @@
+class TestClass
+end
+
+module RSpec
+  module Mocks
+    RSpec.describe ExcludeStubbedClassesFromSubclasses do
+      after do
+        described_class.disable!
+      end
+
+      describe '.enable!' do
+        it 'does not extends Class when it has been enabled' do
+          described_class.enable!
+
+          expect {
+            described_class.enable!
+          }.not_to(change { Class.respond_to?(:subclasses_with_rspec_mocks) })
+        end
+
+        it 'extends RSpec::Mocks with methods' do
+          described_class.enable!
+          expect(RSpec::Mocks).to respond_to(:excluded_subclasses)
+        end
+
+        it 'extends Class with methods' do
+          expect {
+            described_class.enable!
+          }.to change { Class.respond_to?(:subclasses_with_rspec_mocks) }.from(false).to(true)
+        end
+
+        it 'excludes stubbed classes from subclasses' do
+          ::RSpec::Mocks.space.reset_all
+          RSpec::Mocks.configuration.exclude_stubbed_classes_from_subclasses = true
+
+          subclass = Class.new(TestClass)
+          stub_const('TestSubClass', subclass)
+
+          ::RSpec::Mocks.space.reset_all
+          expect(TestClass.subclasses.map(&:object_id)).not_to include(subclass.object_id)
+        end
+      end
+
+      describe '.disable!' do
+        it 'does nothing when it has not been enabled' do
+          expect { described_class.disable! }.not_to raise_error
+        end
+
+        it 'removes methods when it has been enabled' do
+          described_class.enable!
+          expect {
+            described_class.disable!
+          }.to change { Class.respond_to?(:subclasses_with_rspec_mocks) }.from(true).to(false)
+        end
+
+        it 'does not exclude stubbed classes from subclasses' do
+          subclass = Class.new(TestClass)
+
+          stub_const('TestSubClass', subclass)
+
+          ::RSpec::Mocks.space.reset_all
+          expect(TestClass.subclasses).to include(subclass)
+        end
+      end
+    end
+  end
+end

spec/rspec/mocks/mutate_const_spec.rb

@@ -145,6 +145,21 @@ def change_const_value_to(value)
         it 'returns nil' do
           expect(hide_const(const_name)).to be_nil
         end
+
+        describe 'with global exclude_stubbed_classes_from_subclasses option set' do
+          include_context "with isolated configuration"
+
+          before do
+            RSpec::Mocks.configuration.exclude_stubbed_classes_from_subclasses = true
+          end
+
+          it 'gives the same subclasses after rspec clears its mocks' do
+            original_subclasses = TestClass.subclasses
+            stub_const(const_name, Class.new(TestClass))
+            reset_rspec_mocks
+            expect(TestClass.subclasses).to eq(original_subclasses)
+          end
+        end
       end
 
       describe "#hide_const" do
@@ -351,6 +366,21 @@ def change_const_value_to(value)
               end
             end
           end
+
+          describe 'with global exclude_stubbed_classes_from_subclasses option set' do
+            include_context "with isolated configuration"
+
+            before do
+              RSpec::Mocks.configuration.exclude_stubbed_classes_from_subclasses = true
+            end
+
+            it 'gives the same subclasses after rspec clears its mocks' do
+              original_subclasses = TestClass::Nested.subclasses
+              stub_const('TestClass', Class.new(TestClass::Nested))
+              reset_rspec_mocks
+              expect(TestClass::Nested.subclasses).to eq(original_subclasses)
+            end
+          end
         end
 
         context 'for a loaded nested constant' do