Fixed a bug that overwrote existing self.extended method definitions.

There is a hack that dynamically defines self.extended when memo_wise is called, but there was a bug that did not consider the case where an existing self.extended existed, so this has been fixed.

CHANGELOG.md

@@ -11,7 +11,9 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 _No breaking changes!_
 
-**Project enhancements:** none
+**Project enhancements:**
+
+- Fixed a bug that overwrote existing self.extended method definitions. [[#324]](https://github.com/panorama-ed/memo_wise/pull/314)
 
 ## [v1.8.0](https://github.com/panorama-ed/memo_wise/compare/v1.7.0...v1.8.0) - 2023-10-25
 

README.md

@@ -118,15 +118,15 @@ Results using Ruby 3.2.2:
 
 |Method arguments|`Dry::Core`\* (1.0.1)|`Memery` (1.5.0)|
 |--|--|--|
-|`()` (none)|0.54x|3.62x|
-|`(a)`|1.54x|7.74x|
-|`(a, b)`|1.29x|5.58x|
-|`(a:)`|1.55x|12.37x|
-|`(a:, b:)`|1.15x|8.76x|
-|`(a, b:)`|1.15x|8.75x|
-|`(a, *args)`|0.84x|1.54x|
-|`(a:, **kwargs)`|0.79x|2.13x|
-|`(a, *args, b:, **kwargs)`|0.69x|1.38x|
+|`()` (none)|0.59x|3.65x|
+|`(a)`|1.49x|8.38x|
+|`(a, b)`|1.21x|6.55x|
+|`(a:)`|1.43x|13.14x|
+|`(a:, b:)`|1.20x|10.32x|
+|`(a, b:)`|1.18x|10.10x|
+|`(a, *args)`|0.79x|1.61x|
+|`(a:, **kwargs)`|0.75x|1.97x|
+|`(a, *args, b:, **kwargs)`|0.67x|1.37x|
 
 \* `Dry::Core`
 [may cause incorrect behavior caused by hash collisions](https://github.com/dry-rb/dry-core/issues/63).
@@ -135,15 +135,15 @@ Results using Ruby 2.7.8 (because these gems raise errors in Ruby 3.x):
 
 |Method arguments|`DDMemoize` (1.0.0)|`Memoist` (0.16.2)|`Memoized` (1.1.1)|`Memoizer` (1.0.3)|
 |--|--|--|--|--|
-|`()` (none)|24.22x|2.42x|26.43x|2.70x|
-|`(a)`|22.08x|15.19x|22.03x|13.67x|
-|`(a, b)`|19.12x|14.01x|18.60x|12.80x|
-|`(a:)`|30.21x|24.29x|26.43x|23.11x|
-|`(a:, b:)`|27.73x|22.97x|25.11x|21.89x|
-|`(a, b:)`|26.87x|22.76x|23.71x|21.26x|
-|`(a, *args)`|3.15x|2.30x|3.18x|2.11x|
-|`(a:, **kwargs)`|2.89x|2.40x|2.69x|2.28x|
-|`(a, *args, b:, **kwargs)`|2.12x|1.82x|1.96x|1.74x|
+|`()` (none)|23.10x|2.28x|23.77x|2.69x|
+|`(a)`|21.57x|14.28x|20.61x|12.05x|
+|`(a, b)`|19.05x|13.55x|17.83x|11.68x|
+|`(a:)`|30.29x|23.54x|25.22x|21.69x|
+|`(a:, b:)`|27.79x|22.83x|23.78x|21.08x|
+|`(a, b:)`|26.61x|21.40x|21.63x|19.81x|
+|`(a, *args)`|3.16x|2.26x|3.08x|1.97x|
+|`(a:, **kwargs)`|2.74x|2.25x|2.47x|2.10x|
+|`(a, *args, b:, **kwargs)`|2.18x|1.84x|1.93x|1.73x|
 
 You can run benchmarks yourself with:
 

lib/memo_wise.rb

@@ -78,6 +78,14 @@ def initialize(#{all_args})
     end
   HEREDOC
 
+  module CreateMemoWiseStateOnExtended
+    def extended(base)
+      MemoWise::InternalAPI.create_memo_wise_state!(base)
+      super
+    end
+  end
+  private_constant(:CreateMemoWiseStateOnExtended)
+
   # @private
   #
   # Private setup method, called automatically by `prepend MemoWise` in a class.
@@ -136,9 +144,7 @@ def memo_wise(method_name_or_hash)
             #
             # On method call `@_memo_wise` would still be `nil`
             # causing error when fetching cache from `@_memo_wise`
-            def klass.extended(base)
-              MemoWise::InternalAPI.create_memo_wise_state!(base)
-            end
+            klass.singleton_class.prepend(CreateMemoWiseStateOnExtended)
           end
         when Hash
           unless method_name_or_hash.keys == [:self]

spec/memo_wise_spec.rb

@@ -819,5 +819,37 @@ def test_method
         end
       end
     end
+
+    context "with module defined self.extended" do
+      let(:module_with_memo) do
+        Module.new do
+          prepend MemoWise
+
+          def self.extended(base)
+            base.instance_variable_set(:@extended_called, true)
+          end
+
+          def no_args
+            @no_args_counter = no_args_counter + 1
+          end
+          memo_wise :no_args
+
+          def no_args_counter
+            @no_args_counter ||= 0
+          end
+        end
+      end
+
+      it "calls defined self.extended" do
+        klass = Class.new
+        instance = klass.new
+        instance.extend(module_with_memo)
+
+        expect(instance.instance_variable_get(:@extended_called)).to be(true)
+
+        expect(Array.new(4) { instance.no_args }).to all(eq(1))
+        expect(instance.no_args_counter).to eq(1)
+      end
+    end
   end
 end