E3031 'string' does not match '^.*$'

[dr3]

CloudFormation Lint Version

1.17.2

What operating system are you using?

Mac

Describe the bug

(Introduced In 1.17.0, works in 1.16.1)

String does not match '^.*$' (which is regex for "anything")

E3031 '#if($context.identity.claims.account_type == "ADMIN") \n  #return\n#else\n  $util.error("MUST BE ADMIN")\n#end\n' does not match '^.*$'
testing2.yaml:29:7

Expected behavior

It passes

Reproduction template

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Example

Resources:
  GraphQLApi:
    Type: AWS::AppSync::GraphQLApi
    Properties:
      Name: !Ref APIName
      AuthenticationType: OPENID_CONNECT
      OpenIDConnectConfig:
        Issuer: https://securetoken.google.com/foobar

  NoneDataSource:
    Type: AWS::AppSync::DataSource
    Properties:
      ApiId: !GetAtt GraphQLApi.ApiId
      Name: "NoneSource"
      Type: NONE

  AdminOnlyAuthFunction:
    Type: AWS::AppSync::FunctionConfiguration
    Properties:
      ApiId: !GetAtt GraphQLApi.ApiId
      Name: auth_admin_logic
      Description: Must be admin user
      DataSourceName: !GetAtt NoneDataSource.Name
      FunctionVersion: "2018-05-29"
      RequestMappingTemplate: >
        #if($context.identity.claims.account_type == "ADMIN") 
          #return
        #else
          $util.error("MUST BE ADMIN")
        #end
      ResponseMappingTemplate: >
        #return

Parameters:
  APIName:
    Type: String

[kddejong]

Looks like the re.search doesn't do multiline pattern matching so the newlines are throwing it off. Instead of spending resources validating that its a string it just makes sense to remove it. This field is related to some boto automation in which we are taking patterns from botocore. We had an exception for "." so added one for "^.$" as well.