bug#52163: 28.0.60; visual-line-mode breaks C-a and C-e in extreme case

[Phil Sainty <psainty@orcon.net.nz>]

You've convinced me that the existing behaviour isn't a bug, and as
I'm not likely to try to add an alternative this can probably be
closed again (if it was actually re-opened).

I did have one more idea on the matter, though...

On 2022-01-16 23:18, Eli Zaretskii wrote:
>> > IOW, before declaring that there is a problem, please be sure to
>> > consider any reasonable solutions.

I've just remembered `overflow-newline-into-fringe'.  AFAIK that only
has an effect on lines which are *exactly* the window-width characters
wide, but it occurs to me that this fringe behaviour/visualisation
could be used to create a more intuitive solution for the unbreakable
visual line situation, allowing C-e to visually position the cursor at
the end of the visual line (in the fringe) rather than the start of
the next line.

It might be quite a special-case approach -- the fringe position would
be the same position as the start of the next visual line, so Emacs
would need a way to decide which of those two visual places to render
the cursor; and in order for C-a to then move to the start of the same
visual line Emacs would need to know that it had previously been
rendering the cursor in the fringe, so probably the C-a and C-e
commands would be handling this explicitly.

It sounds kinda fiddly/complicated, and I'm not requesting that anyone
tackle this, but I wanted to describe the idea here in case anyone
else thinks it's worth looking into.


-Phil