8000 help() appears confused about the module of typing.Annotated · Issue #89543 · python/cpython · GitHub
[go: up one dir, main page]
Skip to content

help() appears confused about the module of typing.Annotated #89543

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Open
AlexWaygood opened this issue Oct 5, 2021 · 7 comments
Open

help() appears confused about the module of typing.Annotated #89543

AlexWaygood opened this issue Oct 5, 2021 · 7 comments
Labels
3.9 only security fixes 3.10 only security fixes 3.11 only security fixes docs Documentation in the Doc dir stdlib Python modules in the Lib dir topic-typing type-bug An unexpected behavior, bug, or error

Comments

@AlexWaygood
Copy link
Member
BPO 45380
Nosy @gvanrossum, @jack1142, @Fidget-Spinner, @AlexWaygood

Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

Show more details

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-10-05.18:29:03.194>
labels = ['type-bug', '3.9', '3.10', '3.11', 'library', 'docs']
title = 'help() appears confused about the module of typing.Annotated'
updated_at = <Date 2022-02-03.23:18:38.705>
user = 'https://github.com/AlexWaygood'

bugs.python.org fields:

activity = <Date 2022-02-03.23:18:38.705>
actor = 'gvanrossum'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation', 'Library (Lib)']
creation = <Date 2021-10-05.18:29:03.194>
creator = 'AlexWaygood'
dependencies = []
files = []
hgrepos = []
issue_num = 45380
keywords = []
message_count = 3.0
messages = ['403258', '403602', '412485']
nosy_count = 5.0
nosy_names = ['gvanrossum', 'docs@python', 'jack1142', 'kj', 'AlexWaygood']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue45380'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']
@AlexWaygood
Copy link
Member Author

help() appears confused about the module of typing.Annotated. If you call help() on a parameterised "instance" of typing.Annotated, it will claim that Annotated belongs to whatever module the annotated type is from. Additionally, help() appears not to know about the __metadata__ attribute of typing.Annotated.

>>> from typing import Annotated, Callable
>>> t = Annotated[int | str, "Some metadata"]
>>> help(t)
Help on _AnnotatedAlias in module types:

Annotated = int | str
>>> u = Annotated[Callable[[int], str], "Some metadata"]
>>> help(u)
Help on _AnnotatedAlias in module typing:

Annotated = typing.Callable[[int], str]
>>> s = Annotated[int, "Some metadata"]
Help on _AnnotatedAlias in module builtins:

Annotated = class int(object)
 |  int([x]) -> integer
 |  int(x, base=10) -> integer

# (etc., giving the entire output of help() for `int`)

@AlexWaygood AlexWaygood added 3.10 only security fixes 3.9 only security fixes labels Oct 5, 2021
@AlexWaygood AlexWaygood added docs Documentation in the Doc dir stdlib Python modules in the Lib dir type-bug An unexpected behavior, bug, or error 3.10 only security fixes 3.9 only security fixes labels Oct 5, 2021
@AlexWaygood AlexWaygood added docs Documentation in the Doc dir stdlib Python modules in the Lib dir type-bug An unexpected behavior, bug, or error labels Oct 5, 2021
@AlexWaygood
Copy link
Member Author

It actually appears as though there is no documented way to retrieve the metadata from an annotated alias. Is this intentional?

The metadata is stored in a __metadata__ attribute of a typing._AnnotatedAlias instance. But the __metadata__ attribute is undocumented -- there is no mention of it in the docstring for _AnnotatedAlias, in the documentation for typing.Annotated (https://docs.python.org/3.11/library/typing.html#typing.Annotated), or PEP-593, which introduced typing.Annotated (https://www.python.org/dev/peps/pep-0593/).

The documentation says: "Passing include_extras=True to get_type_hints() lets one access the extra annotations at runtime." However, this is misleading. Calling get_type_hints on a function/class where an argument/attribute is annotated with an _AnnotatedAlias instance is a way of retrieving the type hints for the function/class with the _AnnotatedAlias instance unresolved. However, if you call get_type_hints on the _AnnotatedAlias instance directly, this fails.

@AlexWaygood AlexWaygood added 3.11 only security fixes labels Oct 10, 2021
@gvanrossum
Copy link
Member

It looks like __metadata__ was *meant* to be a public attribute, but somehow overseen when the PEP and docs were written. :-(

I don't know anything about this class, really.

@ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
@martindemello
Copy link
Contributor

looks like #96080 fixed this

@Jackenmen
Copy link
Contributor

__metadata__ attribute appears to still not be documented so if it's not tracked elsewhere, it would make sense to make an issue for tracking the documentation about runtime inspection of Annotated.

@martindemello
Copy link
Contributor

also for x = Annotated[int | str, "some metadata"], help(x) returns

Help on _AnnotatedAlias in module typing:

Annotated = int | str

which is less than ideal.

90D3

This was referenced Oct 3, 2022
Open
Closed
@AlexWaygood
Copy link
Member Author

__metadata__ attribute appears to still not be documented so if it's not tracked elsewhere, it would make sense to make an issue for tracking the documentation about runtime inspection of Annotated.

(To update on this: the __metadata__ field is now documented; see the PRs attached to #97797.)

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
3.9 only security fixes 3.10 only security fixes 3.11 only security fixes docs Documentation in the Doc dir stdlib Python modules in the Lib dir topic-typing type-bug An unexpected behavior, bug, or error
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
4 participants
@martindemello @gvanrossum @Jackenmen @AlexWaygood
0