Merge pull request #1276 from glimmerjs/bugfix/do-not-eagerly-consume…

…-args-during-destruction

packages/@glimmer/integration-tests/test/managers/modifier-manager-test.ts

@@ -234,6 +234,52 @@ abstract class ModifierManagerTest extends RenderTest {
       /You attempted to update `foo` on `.*`, but it had already been used previously in the same computation/
     );
   }
+
+  @test
+  'does not eagerly access arguments during destruction'(assert: Assert) {
+    class Foo extends CustomModifier {}
+
+    let foo = this.defineModifier(Foo);
+
+    let Main = defineComponent(
+      { foo },
+      '{{#if @state.show}}<h1 {{foo @state.bar [email protected]}}>hello world</h1>{{/if}}'
+    );
+
+    let barCount = 0;
+    let bazCount = 0;
+
+    class State {
+      @tracked show = true;
+
+      get bar() {
+        if (this.show === false) {
+          barCount++;
+        }
+
+        return;
+      }
+
+      get baz() {
+        if (this.show === false) {
+          bazCount++;
+        }
+
+        return;
+      }
+    }
+
+    let state = new State();
+
+    this.renderComponent(Main, { state });
+
+    state.show = false;
+
+    this.rerender();
+
+    assert.equal(barCount, 0, 'bar was not accessed during detruction');
+    assert.equal(bazCount, 0, 'baz was not accessed during detruction');
+  }
 }
 
 class ModifierManagerTest313 extends ModifierManagerTest {

packages/@glimmer/manager/lib/public/modifier.ts

@@ -112,7 +112,8 @@ export class CustomModifierManager<O extends Owner, ModifierInstance>
 
     let { useArgsProxy, passFactoryToCreate } = delegate.capabilities;
 
-    let args = useArgsProxy ? argsProxyFor(capturedArgs, 'modifier') : reifyArgs(capturedArgs);
+    let argsProxy = argsProxyFor(capturedArgs, 'modifier');
+    let args = useArgsProxy ? argsProxy : reifyArgs(capturedArgs);
 
     let instance: ModifierInstance;
 
@@ -168,7 +169,7 @@ export class CustomModifierManager<O extends Owner, ModifierInstance>
       state.debugName = typeof definition === 'function' ? definition.name : definition.toString();
     }
 
-    registerDestructor(state, () => delegate.destroyModifier(instance, state.args));
+    registerDestructor(state, () => delegate.destroyModifier(instance, argsProxy));
 
     return state;
   }