GeezerVison

sorry, I forgot how python was compiled then :( but I'm pretty sure I compiled it with gcc last time

so I reran the test with the following config args '--enable-optimizations' '--with-lto' 'CC=/usr/bin/clang-18' and got a new result for my bench:

Old version (re.sub): 0.982520s
New version (.replace()): 0.701049s
Difference: 1.40x # sometimes it's 1.35x

and if we rewrite old version of benchmark as you suggested:

_pattern = re.compile(r"[\w\.]+")

def _repl(match):
    text = match.group()
    return text.removeprefix("typing.")

def old_format_annotation(annotation):
    if getattr(annotation, "__module__", None) == "typing":
        return re.sub(_pattern, _repl, repr(annotation))
    return repr(annotation)

we will get a bigger difference:

Old version (re.sub): 1.027774s
New version (.replace()): 0.698902s
Difference: 1.47x # the result can drop to 1.40

P.S.: another reason i like the PR version is because we get rid of the re import that is used once here

Out of curiosity, why use the little replace dance in the refactored code instead of just return repr(annotation).removeprefix("typing.")?

Out of curiosity, why use the little replace dance in the refactored code instead of just return repr(annotation).removeprefix("typing.")?

- Union[typing.List[str], typing.Dict[str, typing.Any]]
+ Union[List[str], Dict[str, Any]]

The replace dance is pretty messy, though, and doesn’t preserve behaviour for footyping.Bar – not that applying a regex to repr output is perfectly reliable to begin with (def foo() -> Literal["typing."]: ...).

For what it’s worth:

pat = re.compile(r"\b(?<!\.)typing\.")
pat.sub("", repr(annotation))

This PR is stale because it has been open for 30 days with no activity.

The PR is stale and has some issues, so I am closing it.

@charmander (or others) Your suggestion looks good (I tested it locally, performance gain is good). Would you like to open a PR?