fix(ivy): detect frozen flyweight objects in definitions and unfreeze

packages/core/src/render3/definition.ts

@@ -17,8 +17,8 @@ import {Type} from '../type';
 import {BaseDef, ComponentDefFeature, ComponentDefInternal, ComponentQuery, ComponentTemplate, ComponentType, DirectiveDefFeature, DirectiveDefInternal, DirectiveType, DirectiveTypesOrFactory, PipeDefInternal, PipeType, PipeTypesOrFactory} from './interfaces/definition';
 import {CssSelectorList, SelectorFlags} from './interfaces/projection';
 
-const EMPTY: {} = {};
-const EMPTY_ARRAY: any[] = [];
+export const EMPTY: {} = {};
+export const EMPTY_ARRAY: any[] = [];
 if (typeof ngDevMode !== 'undefined' && ngDevMode) {
   Object.freeze(EMPTY);
   Object.freeze(EMPTY_ARRAY);

packages/core/src/render3/features/inherit_definition_feature.ts

@@ -8,6 +8,7 @@
 
 import {Type} from '../../type';
 import {fillProperties} from '../../util/property';
+import {EMPTY, EMPTY_ARRAY} from '../definition';
 import {ComponentDefInternal, ComponentTemplate, DirectiveDefFeature, DirectiveDefInternal, RenderFlags} from '../interfaces/definition';
 
 
@@ -47,6 +48,16 @@ export function InheritDefinitionFeature(
     }
 
     const baseDef = (superType as any).ngBaseDef;
+
+    // Some fields in the definition may be empty, if there were no values to put in them that
+    // would've justified object creation. Unwrap them if necessary.
+    if (baseDef || superDef) {
+      const writeableDef = definition as any;
+      writeableDef.inputs = maybeUnwrapEmpty(definition.inputs);
+      writeableDef.declaredInputs = maybeUnwrapEmpty(definition.declaredInputs);
+      writeableDef.outputs = maybeUnwrapEmpty(definition.outputs);
+    }
+
     if (baseDef) {
       // Merge inputs and outputs
       fillProperties(definition.inputs, baseDef.inputs);
@@ -162,3 +173,15 @@ export function InheritDefinitionFeature(
     superType = Object.getPrototypeOf(superType);
   }
 }
+
+function maybeUnwrapEmpty<T>(value: T[]): T[];
+function maybeUnwrapEmpty<T>(value: T): T;
+function maybeUnwrapEmpty(value: any): any {
+  if (value === EMPTY) {
+    return {};
+  } else if (Array.isArray(value) && value === EMPTY_ARRAY) {
+    return [];
+  } else {
+    return value;
+  }
+}

packages/core/test/render3/Inherit_definition_feature_spec.ts

@@ -7,6 +7,7 @@
  */
 
 import {EventEmitter, Output} from '../../src/core';
+import {EMPTY} from '../../src/render3/definition';
 import {InheritDefinitionFeature} from '../../src/render3/features/inherit_definition_feature';
 import {ComponentDefInternal, DirectiveDefInternal, RenderFlags, defineBase, defineComponent, defineDirective} from '../../src/render3/index';
 
@@ -127,6 +128,40 @@ describe('InheritDefinitionFeature', () => {
     });
   });
 
+  it('should detect EMPTY inputs and outputs', () => {
+    class SuperDirective {
+      static ngDirectiveDef = defineDirective({
+        inputs: {
+          testIn: 'testIn',
+        },
+        outputs: {
+          testOut: 'testOut',
+        },
+        type: SuperDirective,
+        selectors: [['', 'superDir', '']],
+        factory: () => new SuperDirective(),
+      });
+    }
+
+    class SubDirective extends SuperDirective {
+      static ngDirectiveDef = defineDirective({
+        type: SubDirective,
+        selectors: [['', 'subDir', '']],
+        factory: () => new SubDirective(),
+        features: [InheritDefinitionFeature]
+      });
+    }
+
+    const subDef = SubDirective.ngDirectiveDef as DirectiveDefInternal<any>;
+
+    expect(subDef.inputs).toEqual({
+      testIn: 'testIn',
+    });
+    expect(subDef.outputs).toEqual({
+      testOut: 'testOut',
+    });
+  });
+
   it('should inherit inputs from ngBaseDefs along the way', () => {
 
     class Class5 {