Can't update deployed API if missing lambda_arn from config

I am setting up Chalice deployment using CodeBuild and I have problem that first deployment works but on second one I get _An error occurred (BadRequestException) when calling the PutIntegration operation: Invalid lambda function_ if Lambda deployed in first time exists.

So if I belive Chalice fails to deploy if it is missing lambda_arn in config file, and because our build always starts from fresh and don't want to put environment specific lambda_arn into repository it will fail.

I think I could add environment dependant configuration files into git and have CodeBuild copy correct one into right place. But would prefer if Chalice could update deployed lambda even without this info, either automatically or by requiring some separate command to load this information from environment it is deploying into. Or have some parameter where you can cleanly give environment config to use.

Start by reproducing the second deployment from a fresh checkout without lambda_arn, then trace the configuration used for the PutIntegration call. Done means an existing deployed Lambda can be updated without storing an environment-specific ARN in the repository, or the supported way to supply that value is clearly defined.

Written by the indexing model from the issue text.