Option with string-splitting *and* specifying option multiple times

[sbellon]

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Example Code

#!/usr/bin/env -S uv run -s
# /// script
# requires-python = ">=3.13"
# dependencies = ['typer']
# ///
 
import enum
import typing
 
import typer
 
app = typer.Typer()
 
 
ALL_CHECKS: typing.Final[dict[str, typing.Callable]] = {
    "one": lambda: ...,
    "two": lambda: ...,
    "three": lambda: ...,
}
 
Checks = enum.StrEnum('Checks', {key.upper(): key for key in ALL_CHECKS})
 
 
def parse_checks(
    ctx: typer.Context, param: typer.CallbackParam, value: str | list[str]
) -> list[Checks]:
    current_checks = ctx.params.get(param.name, [])
    checks = value.split(',') if isinstance(value, str) else value
    return current_checks + list(checks)
 
 
@app.command()
def main(
    checks: typing.Annotated[
        list[Checks],
        typer.Option(
            metavar='CHECK,CHECK,...',
            case_sensitive=False,
            show_default=True,
            help='Checks to execute.',
            callback=parse_checks,
        ),
    ] = list(Checks),
):
    typer.echo(f"Selected checks: {checks}")
 
 
if __name__ == "__main__":
    app()

Description

What works:

$ ./script.py 
Selected checks: [<Checks.ONE: 'one'>, <Checks.TWO: 'two'>, <Checks.THREE: 'three'>]
$ ./script.py --checks one --checks three
Selected checks: [<Checks.ONE: 'one'>, <Checks.THREE: 'three'>]

What does not work:

$ ./script.py --checks one,three --checks two
Usage: script.py [OPTIONS]
Try 'script.py --help' for help.
╭─ Error ──────────────────────────────────────────────────────────────────────────────╮
│ Invalid value for '--checks': 'one,three' is not one of 'one', 'two', 'three'.       │
╰──────────────────────────────────────────────────────────────────────────────────────╯

How can I create an option which I can specify multiple times and each single occurrence splits the given string at a given separator (in this case the comma , character) and in the end I have the list of all given values?

Operating System

Linux, Windows

Operating System Details

No response

Typer Version

0.15.2

Python Version

3.13

Additional Context

No response

[kinuax]

You can achieve it using a parser.

Solution:

def parse_checks(checks: str) -> list[Checks]:
    check_objs = []
    for check in checks.split(","):
        try:
            check_obj = Checks(check)
        except ValueError:
            raise typer.BadParameter(f"{check} should be a valid check.")
        check_objs.append(check_obj)
    return check_objs

def flatten_checks(
    ctx: typer.Context, param: typer.CallbackParam, checks: list[list[Checks]]
) -> list[Checks]:
    return [check for subchecks in checks for check in subchecks]
 
@app.command()
def main(
    checks: typing.Annotated[
        list[list],
        typer.Option(
            metavar='CHECK,CHECK,...',
            case_sensitive=False,
            show_default=True,
            help='Checks to execute.',
            parser=parse_checks,
            callback=flatten_checks,
        ),
    ] = list(Checks),
):
    typer.echo(f"Selected checks: {checks}")

Then it works as expected:

$ ./script.py --checks one,three --checks two
Selected checks: [<Checks.ONE: 'one'>, <Checks.THREE: 'three'>, <Checks.TWO: 'two'>]