Replacement for functools.wraps that preserves signature by embray · Pull Request #2849 · astropy/astropy

embray · 2014-08-11T23:54:41Z

Motivated by this comment I added the make_func_with_sig function to astropy.utils.misc. This enabled me to also write a replacement for functools.wraps that copies the wrapped function's argument signature. Turns out there aren't yet as many places where this is useful as I thought there might be. But it could be useful in the future.

embray · 2014-08-11T23:55:17Z

This could be used to fix #2367 as well.

<astropy#2835 (comment)> this adds the make_func_with_sig function to astropy.utils.misc. Taking advantage of this, a new astropy.utils.compat.misc.wraps function is provided as a replacement for functools.wraps, which provides the same functionality but while also preserving the original wrapped function's signature (so that it displays properly in help())

… thought. And most of them are in utilties/backwards compatibility features that aren't terribly important. But I found this one case where the new wraps implementation is useful. And there could be others in the future.

embray · 2014-08-13T16:31:08Z

Rebased.

embray · 2014-08-14T15:46:15Z

Looks like I might need to fuss with this a bit more. I found some ways in which this seems to break in some cases.

…_sig, rather than only allowing the name of the wrapped function to be used

…eplacement, such that the new function gets the same *name* as the function being wrapped as well

… number into the module make_func_with_sig was called from, and a test to prove that it works.

astrofrog · 2014-08-14T21:56:56Z

@embray - so I tried using functools.wraps from Python 3.4 in the following example:

from functools import wraps

def dec(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        return func(*args, **kwargs)
    return wrapper

@dec
def test(a, b=2):
    """
    Test function
    """
    pass

and when doing test?, the signature is wrong, but when using help(test), it is correct:

In [7]: test?
Type:        function
String form: <function test at 0x106961bf8>
File:        /Users/tom/tmp/test_wraps.py
Definition:  test(*args, **kwargs)
Docstring:   Test function

In [8]: help(test)
Help on function test in module __main__:

test(a, b=2)
    Test function

Is this true also for the workarounds you have here for earlier versions?

astrofrog · 2014-08-14T22:03:31Z

@embray - on the other hand, if I use the decorator package:

from decorator import decorator

@decorator
def dec(func, *args, **kwargs):
    return func(*args, **kwargs)

@dec
def test(a, b=2):
    """
    Test function
    """
    pass

the function signature is correct when doing test?:

In [2]: test?
Type:        function
String form: <function test at 0x1075b7268>
File:        /Users/tom/tmp/test_wraps.py
Definition:  test(a, b=2)
Docstring:   Test function

Maybe we can see what the decorator module does, or maybe even include it in extern and make use of it? What do you think?

(edited example above)

astrofrog · 2014-08-14T22:12:58Z

By the way, good timing, this will be useful for #2855 :)

embray · 2014-08-14T22:19:40Z

My code does a lot of the same stuff as the decorator module, but is a little simpler and IMO easier to understand.

The whole thing here was that on Python 3.4 I was not replacing functools.wraps because help() already works correctly there (as opposed to on previous versions). I didn't realize that the IPython ? syntax did anything special there--I assumed it was delegating to calling help through the underlying kernel. But maybe not?

I could just extend my version of wraps to work on Python 3.4 as well, in which case I might as well move it out of compat and just call it astropy.utils.wraps.

embray · 2014-08-14T22:24:23Z

FWIW if I extended my version of wraps to work on Python 3.4 the test? syntax produced the correct output with the faked signature:

In [5]: test?
Type:        function
String form: <function test at 0x7f426e67c048>
File:        /internal/1/root/src/astropy/astropy/<ipython-input-4-08ff0337b56d>
Definition:  test(a, b=2)
Docstring:   Test function

So it looks like however ? is implemented in IPython it doesn't know how to handle the __wrapped__ attribute added to functions by functools.wraps on Python 3.4. I'll see if I can figure out where to put that in IPython and send them a PR...?

embray · 2014-08-14T22:55:28Z

This fixes the ? issue on IPython: https://github.com/embray/ipython/compare/ipython:master...embray:help-signatures?expand=1 I'll submit a pull request later once I've had time to clean out the accidental whitespace changes

(though really IPython needs a whitespace cleanup in general)

astrofrog · 2014-08-15T05:33:47Z

@embray - great! so for now would it make sense to extend your version of wraps to Python 3.4 for now? Or we could just mark it as a known issue?

astrofrog · 2014-08-15T06:53:47Z

@embray - in any case, this works great on Python <3.4, so 👍 from me! I'd like to use this in #2855.

embray · 2014-08-15T15:44:41Z

I'm thinking for now of extending it for use in Python 3.4 as well, just for consistency's sake. I would also like to do a little performance testing of this, though I don't think its impact is going to be enormous in most areas since in most cases it's a brief one time cost.

…mplementation available on Python 3.4 as well. As such I moved it out of astropy.utils.compat since it's really providing a new function rather than some backward/forward compatibility.

….utils.misc was getting a bit cluttered, so this introduces a few new astropy.utils modules so that astropy.utils.misc could be broken up a bit.

Replacement for functools.wraps that preserves signature

…onger needs to include its own copy of the make_func_with_sig utility. I also renamed make_func_with_sig to make_function_with_signature as suggested here: astropy#2835 (comment) Previously I thought the unabbreviated name was a little on the long side. But on second thought I prefer the clarity here.

… astropy.utils.misc was getting a bit cluttered, so this introduces a few new astropy.utils modules so that astropy.utils.misc could be broken up a bit.

embray added the utils label Aug 11, 2014

embray added this to the v1.0.0 milestone Aug 11, 2014

embray added 2 commits August 13, 2014 12:30

astrofrog mentioned this pull request Aug 14, 2014

Decorator for functions that want to accept NDData #2855

Merged

3 tasks

embray added 4 commits August 14, 2014 16:22

Allow specifying the name of the function generated by make_func_with…

f5e57f6

…_sig, rather than only allowing the name of the wrapped function to be used

Take advantage of the new name-specification feature in the wraps() r…

744b62c

…eplacement, such that the new function gets the same *name* as the function being wrapped as well

Ensure that the filename for the code object is not a .pyc file

85074c0

Trick the compiled code object into also pointing to the correct line…

f845283

… number into the module make_func_with_sig was called from, and a test to prove that it works.

embray added the Affects-release label Aug 14, 2014

Following discussion in astropy#2849, decided to make the new wraps i…

c121150

…mplementation available on Python 3.4 as well. As such I moved it out of astropy.utils.compat since it's really providing a new function rather than some backward/forward compatibility.

embray mentioned this pull request Aug 15, 2014

Reorganize astropy.utils.misc a bit #2857

Merged

Added a changelog entry for astropy#2849 [skip ci]

ad46f7d

embray added a commit that referenced this pull request Aug 15, 2014

Merge pull request #2849 from embray/utils/wraps

196071b

Replacement for functools.wraps that preserves signature

embray merged commit 196071b into astropy:master Aug 15, 2014

embray deleted the utils/wraps branch August 15, 2014 17:43

embray mentioned this pull request Aug 26, 2014

Better support for wrapped function signatures in help ipython/ipython#6362

Closed

pllim mentioned this pull request Dec 21, 2017

Preserve call signature in @deprecated #2367

Closed

Uh oh!

Uh oh!

Conversation

embray commented Aug 11, 2014

Uh oh!

embray commented Aug 11, 2014

Uh oh!

embray commented Aug 13, 2014

Uh oh!

embray commented Aug 14, 2014

Uh oh!

astrofrog commented Aug 14, 2014

Uh oh!

astrofrog commented Aug 14, 2014

Uh oh!

astrofrog commented Aug 14, 2014

Uh oh!

embray commented Aug 14, 2014

Uh oh!

embray commented Aug 14, 2014

Uh oh!

embray commented Aug 14, 2014

Uh oh!

astrofrog commented Aug 15, 2014

Uh oh!

astrofrog commented Aug 15, 2014

Uh oh!

embray commented Aug 15, 2014

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants