inspect.formatargspec fails for keyword args without defaults, affects help and likely pydoc

[dariusp]

BPO	4959
Nosy	@benjaminp
Files	inspect_keyworded_no_default.diff: Patch inspect_keyworded_no_default

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

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GitHub fields:

assignee = None
closed_at = <Date 2009-01-17.04:15:16.827>
created_at = <Date 2009-01-16.05:53:19.652>
labels = ['library', 'type-crash']
title = 'inspect.formatargspec fails for keyword args without defaults, affects help and likely pydoc'
updated_at = <Date 2009-01-17.04:15:16.757>
user = 'https://bugs.python.org/dariusp'

bugs.python.org fields:

activity = <Date 2009-01-17.04:15:16.757>
actor = 'benjamin.peterson'
assignee = 'none'
closed = True
closed_date = <Date 2009-01-17.04:15:16.827>
closer = 'benjamin.peterson'
components = ['Library (Lib)']
creation = <Date 2009-01-16.05:53:19.652>
creator = 'dariusp'
dependencies = []
files = ['12760']
hgrepos = []
issue_num = 4959
keywords = ['patch']
message_count = 2.0
messages = ['79932', '80003']
nosy_count = 2.0
nosy_names = ['benjamin.peterson', 'dariusp']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue4959'
versions = ['Python 3.0', 'Python 3.1']

[dariusp]

Hi,

Suggested log message:
formatargspec now handles keyword only args that don't have defaults.
Previously it expected an empty dict but was being given None.

Patch:
The patch contains a suggested fix to inspect.py and a new test in
test_inspect.py and inspect_fodder2.py to demonstrate the issue.

Before:
>>> def foo(*, a):
...  print(a)
... 
>>> help(foo)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.0/site.py", line 427, in __call__
    return pydoc.help(*args, **kwds)
  File "/usr/local/lib/python3.0/pydoc.py", line 1672, in __call__
    self.help(request)
  File "/usr/local/lib/python3.0/pydoc.py", line 1716, in help
    else: doc(request, 'Help on %s:')
  File "/usr/local/lib/python3.0/pydoc.py", line 1504, in doc
    pager(render_doc(thing, title, forceload))
  File "/usr/local/lib/python3.0/pydoc.py", line 1499, in render_doc
    return title % desc + '\n\n' + text.document(object, name)
  File "/usr/local/lib/python3.0/pydoc.py", line 322, in document
    if inspect.isroutine(object): return self.docroutine(*args)
  File "/usr/local/lib/python3.0/pydoc.py", line 1263, in docroutine
    formatannotation=inspect.formatannotationrelativeto(object))
  File "/usr/local/lib/python3.0/inspect.py", line 895, in formatargspec
    if kwonlyarg in kwonlydefaults:
TypeError: argument of type 'NoneType' is not iterable


After:
>>> def foo(*, a):
...  print(a)
... 
>>> help(foo)

Help on function foo in module __main__:

foo(*, a)

[benjaminp]

Thanks for the patch! Fixed in r68647.