This changes how fish attempts to protect itself from calling tcsetpgrp() too
aggressively. Recall that tcsetpgrp() will "force" itself, if SIGTTOU is
ignored (which it is in fish when job control is enabled).
Prior to this fix, we avoided SIGTTINs by only transferring the tty ownership
if fish was already the owner. This dated from a time before we had really
nailed down how pgroups should be assigned. Now we more deliberately assign a
job's pgroup so we don't need this conservative check.
However we still need logic to avoid transferring the tty if fish is not the
owner. The bad case is when job control is enabled while fish is running in the
background - here fish would transfer the tty and "steal" from the foreground
process.
So retain the checks of the current tty owner but migrate them to the point of
calling tcsetpgrp() itself.
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.
Note: This includes a super cheesy thing to print variable contents.
The expect version has one that's a bit more elaborate (featuring a
marker setup), but tbh that doesn't seem to be worth it.
If we do need it, we can add it, but it seems more likely we'd just do
`set -S`, or do it in a check instead.
Make it easier to use pexpect and to understand its error messages.
Switch to a style in tests using bound methods, which makes them
less noisy to write.
This adds a new interactive test framework based on Python's pexpect. This
is intended to supplant the TCL expect-based tests.
New tests go in `tests/pexpects/`. As a proof-of-concept, the
pipeline.expect test and the (gnarly) bind.expect test are ported to the
new framework.
