Missing auto-generated environment variables in help screen & case-sensitivity

[kdeldycke]

Here is a simple CLI that mixes auto-generated and multiple environment variables:

from click import command, echo, option, pass_context

@command(context_settings={"auto_envvar_prefix": "yo", "show_default": True})
@option("--flag/--no-flag", envvar=["FlAg", "sUper"], show_envvar=True)
@pass_context
def my_cli(ctx, flag):
    echo(f"Flag value: {flag}")

if __name__ == "__main__":
    my_cli()

This produces the following help screen:

$ python ./multiple_envvars.py --help
Usage: multiple_envvars.py [OPTIONS]

Options:
  --flag / --no-flag  [env var: FlAg, sUper; default: no-flag]
  --help              Show this message and exit.

Now let's try a couple of different envvars:

$ FlAg=1 python ./multiple_envvars.py
Flag value: True

$ FlAg=0 python ./multiple_envvars.py
Flag value: False

$ sUper=1 python ./multiple_envvars.py
Flag value: True

$ sUper=0 python ./multiple_envvars.py
Flag value: False

$ yo_FLAG=1 python ./multiple_envvars.py
Flag value: False

$ YO_FLAG=1 python ./multiple_envvars.py
Flag value: True

$ YO_FLAG=0 python ./multiple_envvars.py
Flag value: False

The surprise here is the discovery process of the auto-generated YO_FLAG. I expected it to respect the case-sensitivity of others. but everything auto-generated is uppercased.

So I wonder if we should enforce upper-casing all env vars, whatever their source.

And additionally, shouldn't we add the auto-generated YO_FLAG to the help screen to improve discoverability?

For reference, I ran these test on macOS / zsh, and with the latest click 8.3.1.

[kdeldycke]

Things are a little bit messier than I initially expected.

For instance, if I register explicitly the yo_FLAG as an environment variable on the option, it is properly recognised with its own particular mixed-case. Which highlight the difference of treatment between registered envvar and auto-generated envvar.

I currently mapped all these cases and mismatches on a test case here: https://github.com/kdeldycke/click-extra/blob/48f980b0d6fb1e7ddb914fe03f34d3460c8ef0ca/click_extra/tests/test_parameters.py#L62-L98

I'll continue experimenting with this in my Click Extra project and try to fix this over there.

[davidism]

Environment variables are case sensistive except on Windows. Traditionally, variables are all uppercase, lowercase is usually only seen inside shell scripts. I feel like you're overthinking something here, there's nothing to fix regarding case.