From f83dfd6f5aabdfc1c5363fa8a7f7b8145c8fad92 Mon Sep 17 00:00:00 2001
From: Alan <alan.agius4@gmail.com>
Date: Fri, 28 Jun 2019 13:14:47 +0200
Subject: [PATCH] fix(core): handle `undefined` meta in `injectArgs` (#31333)

In the recent versions of the CLI we introduced a ctor downleveler tranformer for VE JIT builds based on the one found in tsickle, to fix the TDZ issue of `forwardRef`.

However this caused a regression as the injector is not handling that a position `paramType` can be undefined. Which is bubbled down to https://github.com/angular/angular/blob/c6b29f4c6d23b1510db3434cb030203d5bdea119/packages/core/src/di/injector_compatibility.ts#L162 and will crash https://github.com/angular/angular/blob/c6b29f4c6d23b1510db3434cb030203d5bdea119/packages/core/src/di/injector_compatibility.ts#L174-L186

Fixes https://github.com/angular/angular-cli/issues/14888

PR Close #31333
---
 .../core/src/reflection/reflection_capabilities.ts     |  2 +-
 packages/core/test/reflection/reflector_spec.ts        | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/packages/core/src/reflection/reflection_capabilities.ts b/packages/core/src/reflection/reflection_capabilities.ts
index 799d4a4ecd..baadf9a404 100644
--- a/packages/core/src/reflection/reflection_capabilities.ts
+++ b/packages/core/src/reflection/reflection_capabilities.ts
@@ -64,7 +64,7 @@ export class ReflectionCapabilities implements PlatformReflectionCapabilities {
       // migration, but this can be revisited.
       if (typeof paramTypes === 'undefined') {
         result[i] = [];
-      } else if (paramTypes[i] != Object) {
+      } else if (paramTypes[i] && paramTypes[i] != Object) {
         result[i] = [paramTypes[i]];
       } else {
         result[i] = [];
diff --git a/packages/core/test/reflection/reflector_spec.ts b/packages/core/test/reflection/reflector_spec.ts
index 25cb3d0725..ff07f8b1f6 100644
--- a/packages/core/test/reflection/reflector_spec.ts
+++ b/packages/core/test/reflection/reflector_spec.ts
@@ -109,6 +109,16 @@ class TestObj {
         class ForwardDep {}
         expect(reflector.parameters(Forward)).toEqual([[ForwardDep]]);
       });
+
+      it('should not return undefined types for downleveled types', () => {
+        class Dep {}
+
+        class TestService {
+          constructor() {}
+          static ctorParameters = () => [{type: undefined, decorators: []}, {type: Dep}];
+        }
+        expect(reflector.parameters(TestService)).toEqual([[], [Dep]]);
+      });
     });
 
     describe('propMetadata', () => {