Version 0.19.1 breaks default_factory that returns empty list #1353
Description
Fixed in #1350, adding the issue for future reference.
Discussed in #1349
Originally posted by KiSchnelle September 22, 2025
First Check
- I added a very descriptive title here.
- I used the GitHub search to find a similar question and didn't find it.
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Example Code
from dataclasses import dataclass
from typing import Annotated
import typer
app = typer.Typer()
def default_classes() -> list[str]:
return []
@app.command()
@dataclass
class TestCommandd:
classes: Annotated[
list[str],
typer.Option(
default_factory=default_classes,
help="List of classes.",
rich_help_panel="Options",
show_default=False,
),
]
def __post_init__(self) -> None:
print(self.classes)
if __name__ == "__main__":
app()Description
Hi,
I found a for me quite breaking change, probably cause I use it a bit unconventional:D
Probably this pull was the reason.
#1018
In typer version 0.19.0 this returns [] as wanted. In version 0.19.1 this returns the function instead.
I know it's probably not the best way to use like this but I would say it's kind of a breaking change. Anyway if the new way is wanted it should be documented in release notes maybe.
cheers
Kilian
Operating System
Linux
Operating System Details
No response
Typer Version
0.19.0 and 0.19.1
Python Version
3.13.5
Additional Context
No response