At startup we query for
- the cursor position (CSI 6 n)
- kitty keyboard protocol support (CSI ? u)
- terminfo capabilities via XTGETTCAP
Since we don't wait for responses, those can leak into child processes.
Some child processes like fzf cannot decode DCS replies. Plug the
leak by ending each round of querying by asking for the Primary Device
Attribute, and resume input processing only after a response has been
received, (or ctrl-c as an escape hatch).
This is a nice simplification. Tested with the lowest common
denominator (putty, Terminal.app and st).
Fixes#11079
This is somewhat subtle:
The #RUN line in a littlecheck file will be run by a posix shell,
which means the substitutions will also be mangled by it.
Now, we *have* shell-quoted them, but unfortunately what we need is to
quote them for inside a pre-existing layer of quotes, e.g.
# RUN: fish -C 'set -g fish %fish'
here, %fish can't be replaced with `'path with spaces/fish'`, because
that ends up as
# RUN: fish -C 'set -g fish 'path with spaces/fish''
which is just broken.
So instead, we pass it as a variable to that fish:
# RUN: fish=%fish fish...
In addition, we need to not mangle the arguments in our test_driver.
For that, because we insist on posix shell, which has only one array,
and we source a file, we *need* to stop having that file use
arguments.
Which is okay - test_env.sh could previously be used to start a test,
and now it no longer can because that is test_*driver*.sh's job.
For the interactive tests, it's slightly different:
pexpect.spawn(foo) is sensitive to shell metacharacters like space.
So we shell-quote it.
But if you pass any args to pexpect.spawn, it no longer uses a shell,
and so we cannot shell-quote it.
There could be a better way to fix this?
