[Python-Dev] SystemError: new style getargs format but argument is not a tuple

[Serhiy Storchaka]

On 05.01.17 06:43, Terry Reedy wrote:
> On 1/1/2017 6:40 PM, Serhiy Storchaka wrote:
>> On 02.01.17 01:23, Terry Reedy wrote:
>>> There are several recent question on Stackoverflow about
>>>
>>> SystemError: new style getargs format but argument is not a tuple
>
> [snip]
> Resulting from using 3rd party packages.
>
>>> No one commenting has a clue.  Is message from Victor's new calling
>>> code?  Was it backported to 2.7?  Could error be a result of running old
>>> 3rd party binary that needs to be recompiled?
>>
>> A system error "new style getargs format but argument is not a tuple" is
>> not new. It means that PyArg_ParseTuple() is called with not a tuple as
>> the first arguments. This is just a programmical error in third-party
>> extension.
>
> Should the advice in the doc entry for SystemError be changed to include
> this case?
>
> "    You should report this to the author or maintainer of your Python
> interpreter. Be sure to report the version of the Python interpreter
> (sys.version; it is also printed at the start of an interactive Python
> session), the exact error message (the exception’s associated value) and
> if possible the source of the program that triggered the error.
> "

Yes, third-party extensions should be mentioned as a source of 
SystemError. But note that nobody reported this error even on CPython 
bugtracker. I now found questions about this error (related to OpenCV or 
Pillow) asked many years ago on different forums.