From 22681b1bc29ee48b3092d60cfc22726912ae607a Mon Sep 17 00:00:00 2001
From: Jonathan Goldwasser <jogold@users.noreply.github.com>
Date: Tue, 5 Jul 2022 22:04:13 +0200
Subject: [PATCH] fix(route53): cannot delete existing alias record (#20858)

For an alias record, the `ListResourceRecordSets` call returns an empty array
that the `ChangeResourceRecordSets` call doesn't accept.

Remove undefined and empty arrays when calling `ChangeResourceRecordSets`.

See https://github.com/aws/aws-sdk-js/issues/3411

Closes #20847


----

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### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [ ] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/main/INTEGRATION_TESTS.md)?
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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*
---
 .../index.ts                                  | 26 ++++++++---
 ...delete-existing-record-set-handler.test.ts | 46 +++++++++++++++++++
 2 files changed, 65 insertions(+), 7 deletions(-)

diff --git a/packages/@aws-cdk/aws-route53/lib/delete-existing-record-set-handler/index.ts b/packages/@aws-cdk/aws-route53/lib/delete-existing-record-set-handler/index.ts
index e04eb9e6a46b6..1abf667a5ff6e 100644
--- a/packages/@aws-cdk/aws-route53/lib/delete-existing-record-set-handler/index.ts
+++ b/packages/@aws-cdk/aws-route53/lib/delete-existing-record-set-handler/index.ts
@@ -35,15 +35,13 @@ export async function handler(event: AWSLambda.CloudFormationCustomResourceEvent
     ChangeBatch: {
       Changes: [{
         Action: 'DELETE',
-        ResourceRecordSet: {
+        ResourceRecordSet: removeUndefinedAndEmpty({
           Name: existingRecord.Name,
           Type: existingRecord.Type,
-          // changeResourceRecordSets does not correctly handle undefined values
-          // https://github.com/aws/aws-sdk-js/issues/3506
-          ...existingRecord.TTL ? { TTL: existingRecord.TTL } : {},
-          ...existingRecord.AliasTarget ? { AliasTarget: existingRecord.AliasTarget } : {},
-          ...existingRecord.ResourceRecords ? { ResourceRecords: existingRecord.ResourceRecords } : {},
-        },
+          TTL: existingRecord.TTL,
+          AliasTarget: existingRecord.AliasTarget,
+          ResourceRecords: existingRecord.ResourceRecords,
+        }),
       }],
     },
   }).promise();
@@ -54,3 +52,17 @@ export async function handler(event: AWSLambda.CloudFormationCustomResourceEvent
     PhysicalResourceId: `${existingRecord.Name}-${existingRecord.Type}`,
   };
 }
+
+// https://github.com/aws/aws-sdk-js/issues/3411
+// https://github.com/aws/aws-sdk-js/issues/3506
+function removeUndefinedAndEmpty<T>(obj: T): T {
+  const ret: { [key: string]: any } = {};
+
+  for (const [k, v] of Object.entries(obj)) {
+    if (v && (!Array.isArray(v) || v.length !== 0)) {
+      ret[k] = v;
+    }
+  }
+
+  return ret as T;
+}
diff --git a/packages/@aws-cdk/aws-route53/test/delete-existing-record-set-handler.test.ts b/packages/@aws-cdk/aws-route53/test/delete-existing-record-set-handler.test.ts
index 26e8519eb97c5..77d0de4b1b439 100644
--- a/packages/@aws-cdk/aws-route53/test/delete-existing-record-set-handler.test.ts
+++ b/packages/@aws-cdk/aws-route53/test/delete-existing-record-set-handler.test.ts
@@ -133,3 +133,49 @@ test('delete request', async () => {
 
   expect(mockRoute53.changeResourceRecordSets).not.toHaveBeenCalled();
 });
+
+test('with alias target', async () => {
+  mockListResourceRecordSetsResponse.mockResolvedValueOnce({
+    ResourceRecordSets: [
+      {
+        Name: 'dev.cdk.aws.',
+        Type: 'A',
+        TTL: undefined,
+        ResourceRecords: [],
+        AliasTarget: {
+          HostedZoneId: 'hosted-zone-id',
+          DNSName: 'dns-name',
+          EvaluateTargetHealth: false,
+        },
+      },
+    ],
+  });
+
+  mockChangeResourceRecordSetsResponse.mockResolvedValueOnce({
+    ChangeInfo: {
+      Id: 'change-id',
+    },
+  });
+
+  await handler(event);
+
+  expect(mockRoute53.changeResourceRecordSets).toHaveBeenCalledWith({
+    HostedZoneId: 'hosted-zone-id',
+    ChangeBatch: {
+      Changes: [
+        {
+          Action: 'DELETE',
+          ResourceRecordSet: {
+            Name: 'dev.cdk.aws.',
+            Type: 'A',
+            AliasTarget: {
+              HostedZoneId: 'hosted-zone-id',
+              DNSName: 'dns-name',
+              EvaluateTargetHealth: false,
+            },
+          },
+        },
+      ],
+    },
+  });
+});