Support for parameter expansion in --override

[jschwartzentruber]

What's the problem this feature will solve?

Configuration values cannot be overridden (via -x/--override or TOX_OVERRIDE) without losing the ability to use positional arguments in the value.

For example: tox -x "testenv.commands=poetry run pylint {posargs}" --

Describe the solution you'd like

Value substitution should be performed after overrides have been applied to the configuration.

Alternative Solutions

Positional arguments can be put into the override value directly, but only if they are known in advance. An example of a tool that cannot interpolate arguments into the override value is pre-commit.

Bash could also be used to create the override value, but this requires more setup for Windows development.

[gaborbernat]

I do not follow from your examples and description what you're trying to achieve and what's the problem. Please refresh the description with clearer explanation.

[jschwartzentruber]

I do not follow from your examples and description what you're trying to achieve and what's the problem. Please refresh the description with clearer explanation.

Sorry, my example was too convoluted. The motivation is wanting to reuse a testenv by overriding commands so a single testenv can be used for multiple linters. There are other solutions, but I was surprised that {posargs} isn't expanded in -x, so I thought I'd open a request.

[gaborbernat]

The motivation is wanting to reuse a testenv by overriding commands so a single testenv can be used for multiple linters.

That's not supported on purpose. You could create a plugin for adding that support but we don't do that in core.