Add ChangeObserver.unregister

lib/bootsnap/load_path_cache/cache.rb

@@ -114,7 +114,7 @@ def push_paths(sender, *paths)
       def reinitialize(path_obj = @path_obj)
         @mutex.synchronize do
           @path_obj = path_obj
-          ChangeObserver.register(self, @path_obj)
+          ChangeObserver.register(@path_obj, self)
           @index = {}
           @dirs = {}
           @generated_at = now

lib/bootsnap/load_path_cache/change_observer.rb

@@ -56,11 +56,22 @@ def uniq!(*args)
         end
       end
 
-      def self.register(observer, arr)
+      def self.register(arr, observer)
         return if arr.frozen? # can't register observer, but no need to.
 
         arr.instance_variable_set(:@lpc_observer, observer)
-        arr.extend(ArrayMixin)
+        ArrayMixin.instance_methods.each do |method_name|
+          arr.singleton_class.send(:define_method, method_name, ArrayMixin.instance_method(method_name))
+        end
+      end
+
+      def self.unregister(arr)
+        return unless arr.instance_variable_get(:@lpc_observer)
+
+        ArrayMixin.instance_methods.each do |method_name|
+          arr.singleton_class.send(:remove_method, method_name)
+        end
+        arr.instance_variable_set(:@lpc_observer, nil)
       end
     end
   end

test/load_path_cache/change_observer_test.rb

@@ -8,7 +8,7 @@ class ChangeObserverTest < MiniTest::Test
       def setup
         @observer = Object.new
         @arr = []
-        ChangeObserver.register(@observer, @arr)
+        ChangeObserver.register(@arr, @observer)
       end
 
       def test_observes_changes
@@ -31,6 +31,25 @@ def test_observes_changes
         @arr.prepend("j", "k")
       end
 
+      def test_unregister
+        @observer.expects(:push_paths).never
+        @observer.expects(:unshift_paths).never
+        @observer.expects(:reinitialize).never
+
+        ChangeObserver.unregister(@arr)
+
+        @arr << "a"
+        @arr.push("b", "c")
+        @arr.append("d", "e")
+        @arr.unshift("f", "g")
+        @arr.concat(%w(h i))
+        @arr.prepend("j", "k")
+        @arr.delete(3)
+        @arr.compact!
+        @arr.map!(&:upcase)
+        assert_equal %w(J K F G A B C D E H I), @arr
+      end
+
       def test_reinitializes_on_aggressive_modifications
         @observer.expects(:push_paths).with(@arr, "a", "b", "c")
         @arr.push("a", "b", "c")
@@ -45,11 +64,11 @@ def test_reinitializes_on_aggressive_modifications
 
       def test_register_frozen
         # just assert no crash
-        ChangeObserver.register(@observer, @arr.dup.freeze)
+        ChangeObserver.register(@arr.dup.freeze, @observer)
       end
 
       def test_register_twice_observes_once
-        ChangeObserver.register(@observer, @arr)
+        ChangeObserver.register(@arr, @observer)
 
         @observer.expects(:push_paths).with(@arr, "a").once
         @arr << "a"