fix(cloudfront): EdgeFunction fails with newStyleStackSynthesis (#12356)

The `EdgeFunction` construct copied some patterns from CodePipelines to enable
cross-environment interaction. One key difference is that for Lambda@Edge,
CDK assets are created in the cross-environment support stack. This isn't
supported by the BootstraplessSynthesizer, so this custom logic (copied from
CodePipelines) needs to be removed.

The EdgeFunction support stack will now use whatever synthesizer is default for
the current stack.

fixes #12172


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-cloudfront/README.md

@@ -275,6 +275,8 @@ new cloudfront.Distribution(this, 'myDist', {
 > To make it easier to request functions for Lambda@Edge, the `EdgeFunction` construct can be used.
 > The `EdgeFunction` construct will automatically request a function in `us-east-1`, regardless of the region of the current stack.
 > `EdgeFunction` has the same interface as `Function` and can be created and used interchangably.
+> Please note that using `EdgeFunction` requires that the `us-east-1` region has been bootstrapped.
+> See https://docs.aws.amazon.com/cdk/latest/guide/bootstrapping.html for more about bootstrapping regions.
 
 If the stack is in `us-east-1`, a "normal" `lambda.Function` can be used instead of an `EdgeFunction`.
 

packages/@aws-cdk/aws-cloudfront/lib/experimental/edge-function.ts

@@ -6,9 +6,9 @@ import * as iam from '@aws-cdk/aws-iam';
 import * as lambda from '@aws-cdk/aws-lambda';
 import * as ssm from '@aws-cdk/aws-ssm';
 import {
-  BootstraplessSynthesizer, CfnResource, ConstructNode,
+  CfnResource, ConstructNode,
   CustomResource, CustomResourceProvider, CustomResourceProviderRuntime,
-  DefaultStackSynthesizer, IStackSynthesizer, Resource, Stack, Stage, Token,
+  Resource, Stack, Stage, Token,
 } from '@aws-cdk/core';
 import { Construct } from 'constructs';
 
@@ -31,6 +31,9 @@ export interface EdgeFunctionProps extends lambda.FunctionProps {
  * Convenience resource for requesting a Lambda function in the 'us-east-1' region for use with Lambda@Edge.
  * Implements several restrictions enforced by Lambda@Edge.
  *
+ * Note that this construct requires that the 'us-east-1' region has been bootstrapped.
+ * See https://docs.aws.amazon.com/cdk/latest/guide/bootstrapping.html or 'cdk bootstrap --help' for options.
+ *
  * @resource AWS::Lambda::Function
  * @experimental
  */
@@ -214,7 +217,6 @@ export class EdgeFunction extends Resource implements lambda.IVersion {
     let edgeStack = stage.node.tryFindChild(edgeStackId) as Stack;
     if (!edgeStack) {
       edgeStack = new Stack(stage, edgeStackId, {
-        synthesizer: crossRegionSupportSynthesizer(this.stack),
         env: { region: EdgeFunction.EDGE_REGION },
       });
     }
@@ -230,21 +232,6 @@ interface FunctionConfig {
   readonly functionStack: Stack;
 }
 
-// Stolen (and modified) from `@aws-cdk/aws-codepipeline`'s `Pipeline`.
-function crossRegionSupportSynthesizer(stack: Stack): IStackSynthesizer | undefined {
-  // If we have the new synthesizer we need a bootstrapless copy of it,
-  // because we don't want to require bootstrapping the environment
-  // of the account in this replication region.
-  // Otherwise, return undefined to use the default.
-  const scopeStackSynthesizer = stack.synthesizer;
-  return (scopeStackSynthesizer instanceof DefaultStackSynthesizer)
-    ? new BootstraplessSynthesizer({
-      deployRoleArn: scopeStackSynthesizer.deployRoleArn,
-      cloudFormationExecutionRoleArn: scopeStackSynthesizer.cloudFormationExecutionRoleArn,
-    })
-    : undefined;
-}
-
 function addEdgeLambdaToRoleTrustStatement(role: iam.IRole) {
   if (role instanceof iam.Role && role.assumeRolePolicy) {
     const statement = new iam.PolicyStatement();

packages/@aws-cdk/aws-cloudfront/test/experimental/edge-function.test.ts

@@ -1,3 +1,4 @@
+import * as path from 'path';
 import '@aws-cdk/assert/jest';
 import * as cloudwatch from '@aws-cdk/aws-cloudwatch';
 import * as iam from '@aws-cdk/aws-iam';
@@ -227,6 +228,23 @@ test('metric methods', () => {
   }
 });
 
+test('cross-region stack supports new-style synthesis with assets', () => {
+  app = new cdk.App({
+    context: { '@aws-cdk/core:newStyleStackSynthesis': true },
+  });
+  stack = new cdk.Stack(app, 'Stack', {
+    env: { account: '111111111111', region: 'testregion' },
+  });
+
+  new cloudfront.experimental.EdgeFunction(stack, 'MyFn', {
+    code: lambda.Code.fromAsset(path.join(__dirname, 'my-lambda-handler')),
+    handler: 'index.handler',
+    runtime: lambda.Runtime.PYTHON_3_8,
+  });
+
+  expect(() => app.synth()).not.toThrow();
+});
+
 function defaultEdgeFunctionProps(stackId?: string) {
   return {
     code: lambda.Code.fromInline('foo'),

packages/@aws-cdk/aws-cloudfront/test/experimental/my-lambda-handler/index.py

@@ -0,0 +1,4 @@
+def main(event, context):
+    return {
+        'message': 'Hello, world!'
+    }