Strict mode

[aidanheerdegen]

Currently failures to set attributes and expand template variables emit warnings, but are skipped.

This was a conscious design choice so post-processing pipelines are robust and don't fail with small errors.

However, there is a use-case for stricter policing, and failing on these cases when testing a post-processing workflow.

This use-case could be accommodated with a command line argument that upgrades warn to error.

This can be done in-code

# Convert all UserWarnings into errors
warnings.simplefilter("error", UserWarning)

But it is also possible by passing the -W flag to the python interpreter, but that is a bit fiddly with a CLI tool.