redrivePolicy with deadLetterTargetArn for SNS events failed to create AWS::SQS::QueuePolicy

[5up3r20e]

redrivePolicy with deadLetterTargetArn for SNS events failed to create AWS::SQS::QueuePolicy

i found an existent issue but it's already closed #7745

• linked code, refer to https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-join.html aws cloudformation document, you can see the usage here is a bug
  

  serverless/lib/plugins/aws/package/compile/events/sns/index.js

  Lines 119 to 125 in e1ca63c

  	'Fn::Join': [
  	'',
  	`https://sqs.${deRegion}.`,
  	{ Ref: 'AWS::URLSuffix' },
  	`/${deAccount}/${deQueueName}`,
  	],
  	};

serverless.yml

functions:
 handleUserAuthenticated:
    handler: handler.handleUserAuthenticated
    events:
      - sns:
          arn: <snsTopicArn>
          redrivePolicy:
            deadLetterTargetArn: arn:aws:sqs:ap-southeast-2:<accountid>:myDLQ

sls deploy output

Error: The CloudFormation template is invalid: Template error: every Fn::Join object requires two parameters, (1) a string delimiter and (2) a list of strings to be joined or a function that returns a list of strings (such as Fn::GetAZs) to be joined.

Installed version

Framework Core: 2.1.1 (local)
Plugin: 4.0.4
SDK: 2.3.2
Components: 3.1.3

[5up3r20e]

created a pr to fix it #8268

[medikoo]

Thanks @5up3r20e for properly coining that! We will look into PR shortly