Using Annotated on Lists leads to crash

[secretrobotron]

First Check

• I added a very descriptive title here.
• I used the GitHub search to find a similar question and didn't find it.
• I searched the Typer documentation, with the integrated search.
• I already searched in Google "How to X in Typer" and didn't find any information.
• I already read and followed all the tutorials in the docs and didn't find an answer.
• I already checked if it is not related to Typer but to Click.

Commit to Help

• I commit to help with one of those options 👆

Example Code

import typer
from typing import List
from typing_extensions import Annotated

app = typer.Typer()

@app.command()
def test1(test_list: List[int] = typer.Option(default=[1, 2, 3, 4])) -> None:
    for i in test_list:
        print(i)

@app.command()
def test2(test_list: Annotated[List[int], typer.Option(default=[1, 2, 3, 4])]) -> None:
     for i in test_list:
         print(i)

app()

Description

While trying to work around this problem, I ran into a new one. I have (I think) used Annotated correctly, but when I run the example code, I get this error:

AttributeError: 'list' object has no attribute 'isidentifier'

If I comment out test2, it works fine.

The traceback suggests the problem might be within Click, but I'm unsure:

 site-packages/click/core.py:2651 in _parse_decls  

Operating System

macOS

Operating System Details

No response

Typer Version

0.9.4

Python Version

3.11.7

Additional Context

Similar issues:

• TypeError - <argument/option name> is defined twice #834
• Weird behavior when wrongly combining `Annotated` with `List` #713

[svlandeg]

Hi!

You have to declare the default value slightly differently with Annotated. This should work as expected:

import typer
from typing import List
from typing_extensions import Annotated

app = typer.Typer()


@app.command()
def test2(test_list: Annotated[List[int], typer.Option()] = [1, 2, 3, 4]) -> None:
    for i in test_list:
        print(i)


if __name__ == "__main__":
    typer.run(test2)

[ShihaoXu]

Hi, the line

def test2(test_list: Annotated[List[int], typer.Option()] = [1, 2, 3, 4]) -> None:

isn't a perfect solution for the question.
I have two follow up questions:

1. [1, 2, 3, 4] is only initialized once and the same list would be used whenever test2 is called. How can we defined a default_factory for the annotated function parameter?
2. It seems that var: Annotated[X, typer.Option(default=Y)] behaves differently than var: Annotated[X, typer.Option()] = Y in some situations. Is it a desired behavior?

[thht]

I think I have a similar situation here. The following code runs fine when using typer 0.16 and pinning click to <8.2 but fails with TypeError: Secondary flag is not valid for non-boolean flag. on click >=8.2. I hunted it down a bit: Apparently, typer just forwards the default_factory as the default value so the type for click ends up being STRING, which then leads to the confusion.

def get_hashed_default() -> bool:
    config = Config.from_cmdargs()  # This needs typer initialized to work. So we need the default to be a callable.
    return config.hash_subject_ids

@app.command
def foo(hash_subject_ids: Annotated[bool, typer.Option(
        help='Whether to hash the subject IDs. Overrides the `hash_subject_ids` setting.',
        default_factory=get_hashed_default,
        show_default=False,
        ),
    ]
)