Feature request: `sam validate` should validate nested application templates

[davidjb]

Describe your idea/feature/enhancement

It would be helpful that if a SAM template contained AWS::Serverless::Application resources with location Location files that SAM would automatically check these referenced files at the same time. Otherwise, running sam validate or sam validate --lint succeeds, provided the top-level template is valid, giving the false impression that these nested applications' templates are also valid and able to be deployed.

Proposal

Each referenced file could be checked and the console output indicate the specific file(s) that are problematic; cfn-lint supports checking multiple templates in one invocation.

Additional Details

Currently it's possible to specify multiple templates inside .cflintrc but these are ignored by SAM.

[mildaniel]

Thanks @davidjb for the suggestion. I will bring it to the team for prioritization.

[dothomson]

I have also encountered this issue.

I have been led astray by the documentation which states the .cfnlintrc configurations will be used for sam validate --lint.

Since SAM is pre-installed on the github action runners this would save me having to install cfn-lint directly to run the lint to my specifications.

[ribtoks]

This is still a problem

[grayburnd]

Is this in scope for addressing at some point in the near future?