Type hinting for traces_sampler

[Ogaday]

I'm finding the the type declaration of the traces_sampler argument to the sentry_sdk.init constructor a bit problematic.

Environment

• Sentry SaaS (sentry.io)
• Python: sentry-sdk[flask]==0.19.4
• mypy==0.812
• mypy-extensions==0.4.3

Steps to Reproduce

I can't get any variations of the following code to appease mypy:

from typing import Any, Dict, Union
import sentry_sdk


def sampler(context: Dict[str, Any]) -> Union[float, bool]:
    return 1.0


sentry_sdk.init(dsn='', traces_sampler=sampler)

I think think the type declaration (... -> Union[float, bool]) here is sensible. However, because of the declaration here, mypy complains as follows:

sentry.py:9: error: Argument "traces_sampler" to "init" has incompatible type "Callable[[Dict[str, Any]], Union[float, bool]]"; expected "Optional[Callable[[Dict[str, Any]], Union[Real, bool]]]"

If I try something like this instead:

from numbers import Real
from typing import Any, Dict, Union
import sentry_sdk


def sampler(context: Dict[str, Any]) -> Union[Real, bool]:
    return 1.0


sentry_sdk.init(dsn='', traces_sampler=sampler)

I get a different error:

sentry.py:7: error: Incompatible return value type (got "float", expected "Union[Real, bool]")

Which makes sense to me. I also can't delare my return type as Real:

    proba: Real = 1.0
    return proba

gives

sentry.py:7: error: Incompatible types in assignment (expression has type "float", variable has type "Real")

So what is the solution here? Is there a reason Real was chosen as the return type instead of float?

Thanks in advance.

[untitaker]

Yeah that type hint is just plain wrong. Can you file a PR for using a union of float, int and bool instead?

…

On Fri, Apr 16, 2021 at 6:03 PM Ogaday ***@***.***> wrote: I'm finding the the type declaration of the traces_sampler argument to the sentry_sdk.init constructor a bit problematic. Environment - Sentry SaaS (sentry.io) - Python: sentry-sdk[flask]==0.19.4 - mypy==0.812 - mypy-extensions==0.4.3 Steps to Reproduce I can't get any variations of the following code to appease mypy: from typing import Any, Dict, Unionimport sentry_sdk def sampler(context: Dict[str, Any]) -> Union[float, bool]: return 1.0 sentry_sdk.init(dsn='', traces_sampler=sampler) I think think the type declaration (... -> Union[float, bool]) here is sensible. However, because of the declaration here <https://github.com/getsentry/sentry-python/blob/4c09f3203d6d19789c6fa729a2e46557ad4ea913/sentry_sdk/_types.py#L35>, mypy complains as follows: sentry.py:9: error: Argument "traces_sampler" to "init" has incompatible type "Callable[[Dict[str, Any]], Union[float, bool]]"; expected "Optional[Callable[[Dict[str, Any]], Union[Real, bool]]]" If I try something like this instead: from numbers import Realfrom typing import Any, Dict, Unionimport sentry_sdk def sampler(context: Dict[str, Any]) -> Union[Real, bool]: return 1.0 sentry_sdk.init(dsn='', traces_sampler=sampler) I get a different error: sentry.py:7: error: Incompatible return value type (got "float", expected "Union[Real, bool]") Which makes sense to me. I also can't delare my return type as Real: proba: Real = 1.0 return proba gives sentry.py:7: error: Incompatible types in assignment (expression has type "float", variable has type "Real") So what is the solution here? Is there a reason Real was chosen as the return type instead of float? Thanks in advance. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1090>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAGMPROJ53YNSAGYSFD7TB3TJBNUPANCNFSM43BZVFBA> .

[Ogaday]

Done, please let me know if I need to change anything.

In the mean time, I found a workaround for typing a custom traces_sampler as follows:

def traces_sampler(context: Dict[str, Any]) -> Any:
    ...

Which isn't ideal but at least mypy doesn't complain.