Cloudformation circular dependency confusion - amazon-web-services

Question

I'm totally lost on this circular dependency issue with Cloudformation. I wrote this template, and it works great with run from the CLI, but when I try to launch it from the browser as a Stack, I get this circular dependency issue.
Can someone tell me where the dependency is coming from ?
This is the Error I get
Circular dependency between resources: [VehiclesLambda, HelloAPI, AuthorizerFuncPerm]
Here is my template
AWSTemplateFormatVersion: '2010-09-09'
Description: Yes you can use SAM to create an Authorizer
Parameters:
Environment:
Type: String
Default: dev
Outputs:
ExampleAPIUrl:
Value: !Sub "https://${HelloAPI}.execute-api.${AWS::Region}.amazonaws.com/${Environment}/"
Resources:
HelloAPI:
Type: AWS::Serverless::Api
Properties:
StageName: !Sub ${Environment}
DefinitionBody:
swagger: 2.0
info:
title:
Ref: AWS::StackName
securityDefinitions:
test-authorizer:
type: apiKey
name: Authorization
in: header
x-amazon-apigateway-authtype: custom
x-amazon-apigateway-authorizer:
type: token
authorizerUri:
Fn::Sub: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${AuthorizerFunc.Arn}/invocations
authorizerResultTtlInSeconds: 5
paths:
/vehicles:
get:
x-amazon-apigateway-integration:
httpMethod: POST
type: aws_proxy
uri:
!Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${VehiclesLambda.Arn}/invocations
responses: {}
security:
- test-authorizer: []
VehiclesLambda:
Type: AWS::Serverless::Function
Properties:
Handler: index.handler
Runtime: nodejs4.3
CodeUri: 's3://companyrentalaws/vehicles.zip'
MemorySize: 128
Timeout: 30
Policies:
- AWSLambdaBasicExecutionRole
Events:
MyEndpoint:
Type: Api
Properties:
Path: /vehicles
Method: GET
RestApiId:
Ref: HelloAPI
AuthorizerFunc:
Type: AWS::Serverless::Function
Properties:
Handler: authorizer.authorizer
Runtime: nodejs4.3
CodeUri: 's3://companyrentalaws/authorizer.zip'
AuthorizerFuncPerm:
Type: AWS::Lambda::Permission
DependsOn:
- HelloAPI
- AuthorizerFunc
Properties:
Action: lambda:InvokeFunction
FunctionName:
Ref: AuthorizerFunc
Principal: apigateway.amazonaws.com
Sorry for posting so much code, but didn't want to leave anything out.

Answer 1

VehiclesLambda has a property RestApiId which refs HelloAPI.
RestApiId:
Ref: HelloAPI
HelloAPI Fn:GetAttr's VehiclesLambda's Arn
!Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${VehiclesLambda.Arn}/invocations
There is your circular dependency.