Subject: bug#65797: 29.0.92; func-arity should not return (0 . many) with apply-partially

From: Joseph Turner <[email-masked]>
Date: Fri, 08 Sep 2023 09:37:18 -0700

On September 8, 2023 8:52:25 AM PDT, Stefan Monnier <[email-masked]> wrote:
>>> This isn't backwards compatible, is it?
>> Neither is what you propose, AFAIU.  We are in effect changing a
>> public API in incompatible ways.
>
>Yup, AFAICT there's no way to implement the Texinfo-documented
>behavior reliably.
>
>So some backward-incompatibility is inevitable, unless we decide to
>stick to the current code to be "bug compatible" 

IIUC, the patch breaks code that passes a CONDITION predicate that accepts only one argument and also passes an ARG argument.

Is there another case which would break?