Render the command line buffer only until the last line we can fit
on the screen.
If the cursor pushes the viewport such that neither the prompt nor
the first line of the command line buffer are visible, then we are
"scrolled". In this case we need to make sure to erase any leftover
prompt, so add a hack to disable the "shared_prefix" optimization
that tries to minimize redraws.
Down-arrow scrolls down only when on the last line, and up-arrow always
scrolls up as much as possible. This is somewhat unconventional;
probably we should change the up-arrow behavior but I guess it's a
good idea to show the prompt whenever possible. In future we could
solve that in a different way: we could keep the prompt visible even
if we're scrolled. This would work well because at least the left
prompt lives in a different column from the command line buffer.
However this assumption breaks when the first line in the command
line buffer is soft-wrapped, so keep this approach for now.
Note that we're still broken when complete-and-search or history-pager
try to draw a pager on top of an overfull screen. Will try to fix
this later.
Closes#7296
See the changelog additions for user-visible changes.
Since we enable/disable terminal protocols whenever we pass terminal ownership,
tests can no longer run in parallel on the same terminal.
For the same reason, readline shortcuts in the gdb REPL will not work anymore.
As a remedy, use gdbserver, or lobby for CSI u support in libreadline.
Add sleep to some tests, otherwise they fall (both in CI and locally).
There are two weird failures on FreeBSD remaining, disable them for now
https://github.com/fish-shell/fish-shell/pull/10359/checks?check_run_id=23330096362
Design and implementation borrows heavily from Kakoune.
In future, we should try to implement more of the kitty progressive
enhancements.
Closes#10359
