Re: `min-margins' window parameter.

[Eli Zaretskii <eliz@gnu.org>]

> From: Joost Kremers <joostkremers@fastmail.fm>
> Date: Fri, 06 Nov 2020 13:37:24 +0100
> 
> In Emacs 25, the window parameter `min-margins' was added, after several
> discussions here and on bug-gnu-emacs about vertically splitting windows with
> wide margins.
> 
> I've now finally started converting my code to use this parameter,[1] but it
> doesn't seem to be working as expected.
> 
> When I invoke `C-x 3` (`split-window-right`) on a window with
> `visual-fill-column-mode` enabled, the split sometimes works as expected, but
> most of the time it doesn't. What I expect is for the window to be split in to
> side-by-side windows of equal size. What happens most of the time is that the
> window is split into two unevenly-sized windows, with the left window about as
> wide as the text area before the split and the right window taking up the rest
> of the original window.
> 
> Twice during my tests Emacs actually hung, driving one of the CPU cores to 100%.
> 
> I haven't been able to determine when the split works right and when it doesn't.
> It seems to be fairly random. Since all the relevant code runs during redisplay,
> Edebug doesn't seem to work. (At least ISTR that being the case.)

Please submit a full bug report with the details, using "M-x
report-emacs-bug".  Bonus points for showing a recipe for reproducing
the problems without loading visual-fill-column, if possible.

Thanks in advance.