[3.0.0] multiparameter is broken

[TakWolf]

The following code cannot pass in 3.0.0

from typing import Literal

from cyclopts import App

app = App()


@app.default
def main(
        font_sizes: set[Literal[10, 12, 16]] | None = None,
):
    print(font_sizes)


if __name__ == '__main__':
    app()

(.venv) takwolf@TakWolf-MacBook-Pro-2 ark-pixel-font % python -m tools.cli --font-sizes 10 
{10}
(.venv) takwolf@TakWolf-MacBook-Pro-2 ark-pixel-font % python -m tools.cli --font-sizes 10 --font-sizes 12    
{10, 12}
(.venv) takwolf@TakWolf-MacBook-Pro-2 ark-pixel-font % python -m tools.cli --font-sizes 10 12 16
╭─ Error ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ Unused Tokens: ['12', '16'].                                                                                                                                                      │
╰───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

[BrianPugh]

Hi @TakWolf!

This change is intentional; from the v3.0.0 changelog:

When an iterable-like datatype is specified by keyword, only a single element's worth of tokens will be consumed. To restore the old behavior where tokens are consumed until an option-like argument is reached, set Parameter.consume_multiple = True.

This change was made because it led to ambiguous/unintuitive CLIs when the user specifies keyword arguments first. Lets expand your example to the following:

from typing import Literal
from cyclopts import App

app = App()

@app.default
def main(
    font_name: Literal["opensans", "helvetica", "roboto"],
    font_sizes: set[Literal[10, 12, 16]] | None = None,
):
    print(f"{font_name=} {font_sizes=}")

if __name__ == '__main__':
    app()

And this works as expected:

$ python issue-247.py roboto 12 16
font_name='roboto' font_sizes={16, 12}

In cyclopts v2.9.9, if you specify the --font-sizes first, then the positionally supplied font_name will get consumed.

# cyclopts v2.9.9
$ python issue-247.py --font-sizes 12 16 roboto
╭─ Error ───────────────────────────────────────────────────────╮
│ Error converting value "roboto" to Literal[10, 12, 16] for    │
│ "--font-sizes,--empty-font-sizes".                            │
╰───────────────────────────────────────────────────────────────╯

So, in v3, cyclopts does the same as other CLI libraries and only consumes one element worth of tokens at a time when specified by keyword:

# cyclopts v3.0.0
# same command as before
$ python issue-247.py --font-sizes 12 16 roboto
╭─ Error ───────────────────────────────────────────────────────╮
│ Invalid value for "FONT-NAME": unable to convert "16" into    │
│ one of {'opensans', 'helvetica', 'roboto'}.                   │
╰───────────────────────────────────────────────────────────────╯

# specifying it "correctly" now:
$ python issue-247.py --font-sizes 12 --font-sizes 16 roboto
font_name='roboto' font_sizes={16, 12}

If you do not like this new behavior, we can either set Parameter.consume_multiple directly for the parameter, or at an app-level via default_parameter. Updating the original script with default_parameter so that the parsing is more in-line with what you were seeing in cyclopts v2.9.9:

from typing import Literal
from cyclopts import App, Parameter

app = App(
    default_parameter=Parameter(consume_multiple=True),
)

@app.default
def main(
    font_name: Literal["opensans", "helvetica", "roboto"],
    font_sizes: set[Literal[10, 12, 16]] | None = None,
):
    print(f"{font_name=} {font_sizes=}")

if __name__ == '__main__':
    app()

EDIT: removed stuff about things not working as expected; it was a local problem to my setup 🙈