The [disambiguate flag](https://sw.kovidgoyal.net/kitty/keyboard-protocol/#disambiguate) means that:
> In particular, ctrl+c will no longer generate the SIGINT signal,
> but instead be delivered as a CSI u escape code.
so cancellation only works while we turn off disambiguation.
Today we turn it off while running external commands that want to
claim the TTY. Also we do it (only as a workaround for this issue)
while expanding wildcards or while running builtin wait.
However there are other cases where we don't have a workaround,
like in trivial infinite loops or when opening a fifo.
Before we run "while true; end", we put the terminal back in ICANON
mode. This means it's line-buffered, so we won't be able to detect
if the user pressed ctrl-c.
Commit 8164855b7 (Disable terminal protocols throughout evaluation,
2024-04-02) had the right solution: simply disable terminal protocols
whenever we do computations that might take a long time.
eval_node() covers most of that; there are a few others.
As pointed out in #10494, the logic was fairly unsophisticated then:
it toggled terminal protocols many times. The fix in 29f2da8d1
(Toggle terminal protocols lazily, 2024-05-16) went to the extreme
other end of only toggling protocols when absolutely necessary.
Back out part of that commit by toggling in eval_node() again,
fixing cancellation. Fortunately, we can keep most of the benefits
of the lazy approach from 29f2da8d1: we toggle only 2 times instead
of 8 times for an empty prompt.
There are only two places left where we call signal_check_cancel()
without necessarily disabling the disambiguate flag
1. open_cloexec() we assume that the files we open outside eval_node()
are never blocking fifos.
2. fire_delayed(). Judging by commit history, this check is not
relevant for interactive sessions; we'll soon end up calling
eval_node() anyway.
In future, we can leave bracketed paste, modifyOtherKeys and
application keypad mode turned on again, until we actually run an
external command. We really only want to turn off the disambiguate
flag.
Since this is approach is overly complex, I plan to go with either
of these two alternatives in future:
- extend the kitty keyboard protocol to optionally support VINTR,
VSTOP and friends. Then we can drop most of these changes.
- poll stdin for ctrl-c. This promises a great simplification,
because it implies that terminal ownership (term_steal/term_donate)
will be perfectly synced with us enabling kitty keyboard protocol.
This is because polling requires us to turn off ICANON.
I started working on this change; I'm convinced it must work,
but it's not finished yet. Note that this will also want to
add stdin polling to builtin wait.
Closes#10864
Prior to this change, signals.py attempted to generate Ctrl-C (SIGINT) by
sending \x03 to stdin. But with the change to use the CSI U sequence, Ctrl-C no
longer generates SIGINT.
Switch to sending SIGINT directly. Also switch up some of the sleep constants so
that a sleep command can't be confused with another one.
We sometimes leak ^[[I and ^[[O focus reporting events when run from VSCode's
"Run python file" button in the top right corner. To reproduce I installed
the ms-python extension set the VSCode default shell to fish and repeatedly
ran a script that does "time.sleep(1)". I believe VSCode synthesizes keys
and triggers a race condition.
We can probably fix this but I'm not sure when I'll get to it (given how
relatively unimportant this feature is).
So let's go back to the old behavior of only enabling focus reporting in tmux.
I believe that tmux is affected by the same VSCode issue (also on 3.7.1 I
think) but I haven't been able to get tmux to emit focus reporting sequences
yet. Still, keep it to not regress cursor shape (#4788). So far this is
the only motivation for focus reporting and I believe it is only relevant
for terminals that can split windows (though there are a bunch that do).
Closes#10448
Some terminals send the focus-in sequences ("^[I") whenever focus reporting is
enabled. We enable focus reporting whenever we are finished running a command.
If we run two commands without reading in between, the focus sequences
will show up on the terminal.
Fix this by enabling focus-reporting as late as possible.
This fixes the problem with `^[I` showing up when running "cat" in
gnome-terminal https://github.com/fish-shell/fish-shell/issues/10411.
This begs the question if we should do the same for CSI u and bracketed paste.
It's difficult to answer that; let's hope we find motivating test cases.
If we enable CSI u too late, we might misinterpret key presses, so for now
we still enable those as early as possible.
Also, since we now read immediately after enabling focus events, we can get
rid of the hack where we defer enabling them until after the first prompt.
When I start a fresh terminal, the ^[I no longer shows up.
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
This starts two sleep processes and expects them to be killed on
SIGHUP.
Unfortunately, if this ever fails the second run will also fail
because it'll see the old sleep still lying around (because it'll run
for 130 seconds).
So, what we do is:
1. Keep the pids for these specific sleeps
2. Check if any of them are still running (and only fail for them)
3. Kill them from python
Fixes#9152
On macOS, the tests would often fail because calls to `pkill` would "leak"
across tests: kill processes run by other tests. This is because on macOS,
the -P argument to pkill must come before the process name. On Linux it
doesn't matter.
This improves test reliability on Mac.
This disables job control inside command substitutions. Prior to this
change, a cmdsub might get its own process group. This caused it to fail
to cancel loops properly. For example:
while true ; echo (sleep 5) ; end
could not be control-C cancelled, because the signal would go to sleep,
and so the loop would continue on. The simplest way to fix this is to
match other shells and not use job control in cmdsubs.
Related is #1362
I really kinda hate how insistent clang-format is to have line
breaks *IFF THE LINE IS TOO LONG*.
Like... lemme just add a break if it looks better, will you?
But it is the style at this time, so we shall tie an onion to our
belt.
