inspect.getcallargs()

[gsakkis]

BPO	3135
Nosy	@benjaminp
Files	getcallargs.patch getcallargs2.patch

^{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 2010-03-30.17:59:44.555>
created_at = <Date 2008-06-18.22:16:52.950>
labels = ['type-feature', 'library']
title = 'inspect.getcallargs()'
updated_at = <Date 2010-03-30.17:59:44.553>
user = 'https://bugs.python.org/gsakkis'

bugs.python.org fields:

activity = <Date 2010-03-30.17:59:44.553>
actor = 'benjamin.peterson'
assignee = 'none'
closed = True
closed_date = <Date 2010-03-30.17:59:44.555>
closer = 'benjamin.peterson'
components = ['Library (Lib)']
creation = <Date 2008-06-18.22:16:52.950>
creator = 'gsakkis'
dependencies = []
files = ['16587', '16591']
hgrepos = []
issue_num = 3135
keywords = ['patch']
message_count = 10.0
messages = ['68378', '87787', '87788', '101303', '101326', '101327', '101339', '101341', '101348', '101951']
nosy_count = 3.0
nosy_names = ['gsakkis', 'benjamin.peterson', 'Alexander.Belopolsky']
pr_nums = []
priority = 'normal'
resolution = 'accepted'
stage = None
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue3135'
versions = ['Python 2.7']

[gsakkis]

I'd like to propose a new function for inclusion to the inspect module
-- getcallargs(func, *args, **kwds) -- that returns a dict which maps
the formal arguments of a function (or other callable) to the values
passed as args and kwds, just as Python has to do when calling
func(*args, **kwds). For example:

>>> def func(a, b='foo', c=None, *x, **y):
...         pass
>>> sorted(getcallargs(func, 5, z=3, b=2).items())
 [('a', 5), ('b', 2), ('c', None), ('x', ()), ('y', {'z': 3})]

This is handy when writing decorators, or more generally when one would
want to do some minimal type checking without actually calling the function.

I have posted a recipe at
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/551779; I can
clean it up and submit a proper patch if it's deemed useful enough for
the stdlib.

[gsakkis]

I updated the recipe to also return a missing_args tuple - the tuple
of the formal parameters whose value was not provided. This is useful in
cases where one want to distinguish f() from f(None) given "def f(x=None)".

[gsakkis]

Also updated url: http://code.activestate.com/recipes/551779/

[gsakkis]

I reverted the function to the original API (return just the dict with the bindings), cleaned it up, wrote thorough unit tests and made a patch against Python 2.7a4.

[gsakkis]

Renamed the Testcase classes to conform with the rest in test_inspect.py, added a few more tests for tuple args and patched against the latest trunk (r79086).

[benjaminp]

The patch will also need docs in inspect.rst.

[gsakkis]

• Added docs in inspect.rst
• Fixed TypeError message for zero-arg functions ("takes no arguments" instead of "takes exactly 0 arguments") + added test.

[benjaminp]

Would you upload this patch to Rietveld for review?

[gsakkis]

Uploaded at http://codereview.appspot.com/659041/show

[benjaminp]

Applied in r79500. Note I removed the error checking that a bound method received an instance of the class as the first argument because that error checking is a function of the calling of the function, not the binding of the arguments.