Missing Signature Info for Builtin Exceptions in help() and Docs

[ericsnowcurrently]

Bug report

Bug description:

(I've tagged this as a "docs" issue because help() is arguably a part of the documentation. Also, some of the docs entries have a similar lack of details. I suppose that could be dealt with separately.)

The help() text for (at least some) builtin exceptions doesn't show the type-specific signature for __init__() (or __new__()), instead showing a generic one with (self, /, *args, **kwargs).

Here's an example (in the REPL) ¹:

>>> help(ExceptionGroup)
 | ...
 |  __init__(self, /, *args, **kwargs)
 |      Initialize self.  See help(type(self)) for accurate signature.
 | ...

(The help() entry for __new__() is likewise unhelpful.)

There is a similar lack of information in the docs, though a handful of entries have at least some signature information.

All builtin exceptions (best effort catalog):

exception type	expected* (approximately) (incl. additional forms)	docs have sig
Exception BaseException	__init__(self, /, *args)
ExceptionGroup BaseExceptionGroup	__init__(self, msg, excs, /)	X†
StopIteration	__init__(self, value=None, /, *args)
SystemExit	__init__(self, code=None, /, *args)
ImportError	__init__(self, /, name=None, path=None, name_from=None)
OSError	__init__(self, errno, strerror, filename=None, winerror=None, filename2=None, /)	X†
^^^^^	__init__(self, arg=None, /)	X†
^^^^^	__init__(self, /, *args)	‡
NameError	__init__(self, /, *args, name=None)
AttributeError	__init__(self, /, *args, name=None, obj=None)
SyntaxError	__init__(self, msg, details, /)	X†
^^^^^	__init__(self, msg=None, /, *args)	‡
UnicodeEncodeError	__init__(self, encoding, obj, start, end, reason, /)
UnicodeDecodeError	__init__(self, encoding, obj, start, end, reason, /)
UnicodeTranslateError	__init__(self, obj, start, end, reason, /)
-- all others (?) --	-- same as Exception/BaseException --

* I derived expected signatures from the content of Objects/exceptions.c.
† The doc entries for OSError, ExceptionGroup, and SyntaxError imply that they each take keyword arguments but they do not.
‡ The doc entries for OSError and SyntaxError do not include the alternate signature.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Footnotes

1. FYI, I don't mean to pick on ExceptionGroup. It happened to be the one for which I first noticed the problem. ↩

[brian030128]

Hi I would like to work on this!