If the backgrounded/stopped job was using the tty, sending it SIGCONT first
might cause it to immediately wake and try to use the tty (which fish still has
control over), causing it to immediately stop again after receiving a SIGTTOU.
We are supposed to send SIGHUP first so that when the process resumes it sees
the queued SIGHUP and executes its registered handler!
While obtaining an uncontested mutex from the same thread (without reentrance)
is basically ~free, the use of `MainThread<RefCell<T>>` instead of `Mutex<T>`
makes it clear that there is no actual synchronization taking place, hopefully
making the code easier to understand.
On this binding we fail to disable CSI u
bind c-t '
begin
set -lx FZF_DEFAULT_OPTS --height 40% --bind=ctrl-z:ignore
eval fzf | while read -l r; echo read $r; end
end
'
because for "fzf", ParseExecutionContext::setup_group() returns early with the
parent process group (which should be fish's own) , hence "wants_terminal"
is false. This seems questionable, I don't think the eval should make a
difference here.
For now, don't touch it; use the more accurate way of detecting whether
a process may read keyboard input. In many of such cases "wants_terminal"
is false, like
echo (echo 1\n2\n3 | fzf)
Fixes#10504
Running
echo foo | vim -
gets us in a weird situation because we put the job in fish's process groups.
It causes us to not set a PGID for this job, so it can't be resumed among
other things.
Stopping the job with ctrl-z and try to exit the shell causes a crash in the
"There are still jobs active" warning because the PID for the job is still 0.
Let's remove the assertion to restore previous behavior, and hopefully fix
this later.
We enable terminal protocols once at startup, and disable them before exit.
Additionally, we disable them while evaluating commands (see 8164855b7 (Disable
terminal protocols throughout evaluation, 2024-04-02))..
Thirdly, we re-enable protocols inside builtin read (where it's disabled
because we are evaluating something). All of these three are scoped and
statically guaranteed to not leak into each others scopes.
There is another place where we enable protocols non-scoped: when we
receive a notification that a job is stopped. If this is ever hit, things
will be imbalanced and we'll fail to restore the right terminal state,
or (more likely) crash due the assertion in terminal_protocols_enable().
This code path used to be necessary when we disabled protocols only while
actually executing an external command but we changed that in 8164855b7,
so it should no longer be. Remove it.
I haven't been able to find a test case, I'll try to do that later.
The main reason we changed the scope of protocols was focus reporting (#10408).
We have given up on that for now (outside tmux where I can't get it to work)
so we might want to reconsider and go back to the "optimized" approach of
enabling it for as long as possible. But this is simpler, easier to verify.
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
