From 82e3f546dbedbab273bf66536a36f7add837b166 Mon Sep 17 00:00:00 2001
From: Eduardo Speroni <edusperoni@gmail.com>
Date: Wed, 25 Nov 2020 19:52:53 -0300
Subject: [PATCH] fix(zone.js): patch child method that overrides an already
 patched method (#39850)

Fix a case where, if the parent class had already been patched, it would
not patch the child class. In addition to checking if the method is
defined in the prototype, and not inherited, it also does the same for
the unpatched method.

PR Close #39850
---
 packages/zone.js/lib/common/utils.ts      |   2 +-
 packages/zone.js/test/common/util.spec.ts | 120 ++++++++++++++++++++++
 2 files changed, 121 insertions(+), 1 deletion(-)

diff --git a/packages/zone.js/lib/common/utils.ts b/packages/zone.js/lib/common/utils.ts
index f319b4bdc8..28a58f0ff1 100644
--- a/packages/zone.js/lib/common/utils.ts
+++ b/packages/zone.js/lib/common/utils.ts
@@ -402,7 +402,7 @@ export function patchMethod(
 
   const delegateName = zoneSymbol(name);
   let delegate: Function|null = null;
-  if (proto && !(delegate = proto[delegateName])) {
+  if (proto && (!(delegate = proto[delegateName]) || !proto.hasOwnProperty(delegateName))) {
     delegate = proto[delegateName] = proto[name];
     // check whether proto[name] is writable
     // some property is readonly in safari, such as HtmlCanvasElement.prototype.toBlob
diff --git a/packages/zone.js/test/common/util.spec.ts b/packages/zone.js/test/common/util.spec.ts
index 65c138a33b..c790f360ef 100644
--- a/packages/zone.js/test/common/util.spec.ts
+++ b/packages/zone.js/test/common/util.spec.ts
@@ -77,6 +77,126 @@ describe('utils', function() {
       expect(desc!.writable).toBeTruthy();
       expect(!desc!.get).toBeTruthy();
     });
+
+    it('should patch target if it overrides a patched method', () => {
+      let args: any[]|undefined;
+      let childArgs: any[]|undefined;
+      let self: any;
+      let childSelf: any;
+      class Type {
+        method(..._args: any[]) {
+          args = _args;
+          self = this;
+          return 'OK';
+        }
+      }
+      class ChildType extends Type {
+        method(..._args: any[]) {
+          childArgs = _args;
+          childSelf = this;
+          return 'ChildOK';
+        }
+      }
+
+      const method = Type.prototype.method;
+      const childMethod = ChildType.prototype.method;
+      let delegateMethod: Function;
+      let delegateSymbol: string;
+      let childDelegateMethod: Function;
+      let childDelegateSymbol: string;
+
+      const typeInstance = new Type();
+      const childTypeInstance = new ChildType();
+      expect(patchMethod(
+                 Type.prototype, 'method',
+                 (delegate: Function, symbol: string, name: string) => {
+                   expect(name).toEqual('method');
+                   delegateMethod = delegate;
+                   delegateSymbol = symbol;
+                   return function(self, args) {
+                     return delegate.apply(self, ['patch', args[0]]);
+                   };
+                 }))
+          .toBe(delegateMethod!);
+
+      expect(patchMethod(
+                 ChildType.prototype, 'method',
+                 (delegate: Function, symbol: string, name: string) => {
+                   expect(name).toEqual('method');
+                   childDelegateMethod = delegate;
+                   childDelegateSymbol = symbol;
+                   return function(self, args) {
+                     return delegate.apply(self, ['child patch', args[0]]);
+                   };
+                 }))
+          .toBe(childDelegateMethod!);
+
+      expect(typeInstance.method('a0')).toEqual('OK');
+      expect(childTypeInstance.method('a0')).toEqual('ChildOK');
+      expect(args).toEqual(['patch', 'a0']);
+      expect(childArgs).toEqual(['child patch', 'a0']);
+      expect(self).toBe(typeInstance);
+      expect(childSelf).toBe(childTypeInstance);
+      expect(delegateMethod!).toBe(method);
+      expect(childDelegateMethod!).toBe(childMethod);
+      expect(delegateSymbol!).toEqual(zoneSymbol('method'));
+      expect(childDelegateSymbol!).toEqual(zoneSymbol('method'));
+      expect((Type.prototype as any)[delegateSymbol!]).toBe(method);
+      expect((ChildType.prototype as any)[delegateSymbol!]).toBe(childMethod);
+    });
+
+    it('should not patch target if does not override a patched method', () => {
+      let args: any[]|undefined;
+      let self: any;
+      class Type {
+        method(..._args: any[]) {
+          args = _args;
+          self = this;
+          return 'OK';
+        }
+      }
+      class ChildType extends Type {}
+      const method = Type.prototype.method;
+      let delegateMethod: Function;
+      let delegateSymbol: string;
+      let childPatched = false;
+
+      const typeInstance = new Type();
+      const childTypeInstance = new ChildType();
+      expect(patchMethod(
+                 Type.prototype, 'method',
+                 (delegate: Function, symbol: string, name: string) => {
+                   expect(name).toEqual('method');
+                   delegateMethod = delegate;
+                   delegateSymbol = symbol;
+                   return function(self, args) {
+                     return delegate.apply(self, ['patch', args[0]]);
+                   };
+                 }))
+          .toBe(delegateMethod!);
+
+      expect(patchMethod(
+                 ChildType.prototype, 'method',
+                 (delegate: Function, symbol: string, name: string) => {
+                   childPatched = true;
+                   return function(self, args) {
+                     return delegate.apply(self, ['child patch', args[0]]);
+                   };
+                 }))
+          .toBe(delegateMethod!);
+
+      expect(childPatched).toBe(false);
+      expect(typeInstance.method('a0')).toEqual('OK');
+      expect(args).toEqual(['patch', 'a0']);
+      expect(self).toBe(typeInstance);
+      expect(delegateMethod!).toBe(method);
+      expect(delegateSymbol!).toEqual(zoneSymbol('method'));
+      expect((Type.prototype as any)[delegateSymbol!]).toBe(method);
+      expect(childTypeInstance.method('a0')).toEqual('OK');
+      expect(args).toEqual(['patch', 'a0']);
+      expect(self).toBe(childTypeInstance);
+      expect((ChildType.prototype as any)[delegateSymbol!]).toBe(method);
+    });
   });
 
   describe('patchPrototype', () => {