aws-sam-cli Bug: sam validate does not support language extension

Description:

sam validate command does not support AWS Language Extensions although it was mentioned to be patched in version 1.56.1.

Also mentioned here

Steps to reproduce:

Create a new project with Poetry: poetry new sam-validate-test
Install aws-sam-cli: poetry add aws-sam-cli
Create a new SAM template with AWS Language Extensions support:

such as:

AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::LanguageExtensions'

Parameters:
...

Resources:
  TestBucket:
  Type: AWS::S3::Bucket
  Properties:
  ... 
    UpdateReplacePolicy: !If [IsDevDeployment, "Delete", "Retain"]
    DeletionPolicy: !If [IsDevDeployment, "Delete", "Retain"]

Validate the SAM template with SAM CLI: sam validate -t template.yaml

Observed result:

The command fails with the following error message:

Error: [InvalidTemplateException('Every DeletionPolicy member must be a string.')] Every DeletionPolicy member must be a string.

Expected result:

There should be no error message

Additional environment details (Ex: Windows, Mac, Amazon Linux etc)

SAM CLI, version 1.76.0

❯ sam --info
{
  "version": "1.76.0",
  "system": {
    "python": "3.9.5",
    "os": "Linux-5.10.16.3-microsoft-standard-WSL2-x86_64-with-glibc2.31"
  },
  "additional_dependencies": {
    "docker_engine": "Not available",
    "aws_cdk": "2.53.0 (build 7690f43)",
    "terraform": "Not available"
  }
}

Mar 08 '23 15:03 napso

Hi @napso, thanks for raising this issue!

SAM CLI doesn't support language extensions with sam validate command as of now, other commands should be working as expected. I will flag this feature request and take it to our PMs.

Mar 08 '23 22:03 mndeveci

Hi @napso, thanks for raising this issue!

SAM CLI doesn't support language extensions with sam validate command as of now, other commands should be working as expected. I will flag this feature request and take it to our PMs.

I see, thank you.

Mar 09 '23 08:03 napso