There was an issue (#16299) that was caused by the get functions in numpy.compat._inspect not handling keyword-only arguments (PEP 3102 asterisk style). The functions would ignore the keyword-only arguments, which either lead to incomplete or incorrect output.

#16541 fixed this issue partially. However, I missed two issues:

1. verify_matching_signatures(lambda a, *, foo=1: 0, lambda a, foo=None: 0) will pass because it treats foo the same, regardless of whether it is kwonly. This is probably not the intended behaviour. As such, arguments that are keyword-only would need to be treated differently from those that are not, which would require changing the return of the function.

2. formatargspec and formatargvalues do not handle kwonly arguments, similar to above. As such, format(get(...)) would strip out the kwonly property of arguments. Since this method is used to establish signatures elsewhere, it is probably not the intended behaviour. Fixing this would require changing the arguments of the format functions to match the change discussed above.

Since this would require changing the signatures of these functions, I'd like some input on whether this should be done. The proposal would be to modify the functions as follows:

# Old returns
def getargs(co):
    # ...
    return args, varargs, varkw

# New returns
def getargs(co):
    # ...
    return args, kwonlyargs, varargs, varkw


# Old returns
def getargspec(func):
    # ...
    return args, varargs, varkw, func.__defaults__

# New returns
def getargspec(func):
    # ...
    return args, kwonlyargs, varargs, varkw, func.__defaults__, tuple(func.__kwdefaults__.values())

And similarly, the signatures of format:

# Old signature
def formatargspec(args, varargs=None, varkw=None, defaults=None,
                  formatarg=str,
                  formatvarargs=lambda name: '*' + name,
                  formatvarkw=lambda name: '**' + name,
                  formatvalue=lambda value: '=' + repr(value),
                  join=joinseq):
    # ...
# New signature
def formatargspec(args, kwonlyargs=None, varargs=None, varkw=None, defaults=None, kwdefaults=None,
                  formatarg=str,
                  formatvarargs=lambda name: '*' + name,
                  formatvarkw=lambda name: '**' + name,
                  formatvalue=lambda value: '=' + repr(value),
                  join=joinseq):
    # ...

# Old signature
def formatargvalues(args, varkw, varargs, locals,
                    formatarg=str,
                    formatvarargs=lambda name: '*' + name,
                    formatvarkw=lambda name: '**' + name,
                    formatvalue=lambda value: '=' + repr(value),
                    join=joinseq)
    # ...

# New signature
def formatargvalues(args, kwonlyargs, varargs, varkw, locals,
                    formatarg=str,
                    formatvarargs=lambda name: '*' + name,
                    formatvarkw=lambda name: '**' + name,
                    formatvalue=lambda value: '=' + repr(value),
                    join=joinseq)
    # ...

This should not interfere with anything, unless it was relying on incorrect behaviour by ignoring kwonly arguments. The usages that pycharm detects are:

formatargspec:

• numpy.ma.core.get_object_signature which is simply formatargspec(*getargspec(obj)) and will remain unaffected.

formatargvalues:

• No usage found

getargspec:

• numpy.core.overrides.verify_matching_signatures will be fixed as per issue BUG: numpy.core.overrides.verify_matching_signatures ignores keyword-only arguments #16299
• numpy.ma.core.get_object_signature unaffected as per the formatargspec usage.

getargs:

• numpy.compat._inspect.getargspec is being fixed, changing returns
• numpy.compat._inspect.getargvalues would probably also need to have returns changed, though I cannot see any usage

I'm not familiar enough with the project to know whether there are could be any usages that can't be detected.

If this seems like a reasonable change I will add it and create a PR.