Subject: Re: bug#57179: 29.0.50: 'wrong-number-of-arguments' for function of two arguments called from 'window-scroll-functions'

From: Michael Heerdegen <[email-masked]>
Date: Sat, 13 Aug 2022 22:50:47 +0200

Eli Zaretskii <[email-masked]> writes:

> The backtrace seems to show that a function that is called is
> different from the one you show as your hook function.  So I think you
> should look closer into how you set up window-scroll-functions.

I too have seen this problem just yesterday.  There must be something
going on, it is unlikely that this is a coincidence.

In the backtrace I saw that the function had been called by name with
zero arguments.  But on top of the backtrace the symbol-function had
been shown (a closure).  I also wondered about that.

I verified that the function was only accessible via
`window-scroll-functions'.  My code did not use the function in any
other place.

Some entries below in the backtrace was `redisplay' - so... somehow
`redisplay' is sometimes calling functions in `window-scroll-functions'
with zero arguments.  Maybe the buffer local binding of
`window-scroll-functions'.

Please tell whether this information suffices and you already have some
idea or if I should try to create a recipe.  I guess this must be
related to a recent change from within the last few days.

Michael.