If fish launches a program and that program marks stdin as O_ASYNC, then
fish will start receiving SIGIO events on Mac. This occurs even though
the file descriptor itself does not have the O_ASYNC flag set.
SIGIO is reported as interrupting select which then breaks multiple-key
bindings, especially in vi-mode.
As the SIGIO based universal notifier is disabled, remove it and the
SIGIO handler itself. This allows fish to ignore properly ignore SIGIO.
Fixes#7853
This fixes up the SIGIO notifier in preparation for using it on BSD. It
removes the reliance on the signal's si_code, which is not available in
BSD, and it properly handles the BSD behavior where SIGIO is delivered on
a read even if the read returns EAGAIN.
Introduce a new strategy for notifying other fish processes of universal
variable changes, as a planned replacement for the complex
strategy_named_pipe. The new strategy still uses a named pipe, but instead
of select() on it, it arranges for SIGIO to be delivered when data is
available. If a SIGIO has been seen since the last check, it means the file
needs to be re-read.
The topic monitor allows a client to wait for multiple events, e.g. sigchld
or an internal process exit. Prior to this change a client had to specify
the list of generations and the list of topics they are interested in.
Simplify this to just the list of generations, with a max-value generation
meaning the topic is not interesting.
Also remove the use of enum_set and enum_array, it was too complex for what
it offered.
When fish receives a "cancellation inducing" signal (SIGINT in particular)
it has to unwind execution - for example while loops or whatever else that
is executing. There are two ways this may come about:
1. The fish process received the signal
2. A child process received the signal
An example of the second case is:
some_command | some_function
Here `some_command` is the tty owner and so will receive control-C, but
then fish has to cancel function execution.
Prior to this change, these were handled uniformly: both would just set a
cancellation signal inside the parser. However in the future we will have
multiple parsers and it may not be obvious which one to set the flag in.
So instead distinguish these cases: if a process receives SIGINT we mark
the signal in its job group, and if fish receives it we set a global
variable.
This makes it possible to expand the signals checked by the type. I can't merge
the sigttin fixes for #7060 yet because they introduce new breakage, but this
will make merging any future fix easier.
We used to have a global notion of "is the shell interactive" but soon we
will want to have multiple independent execution threads, only some of
which may be interactive. Start tracking this data per-parser.
Now that our interactive signal handlers are a strict superset of
non-interactive ones, there is no reason to "reset" signals or take action
when becoming non-interactive. Clean up how signal handlers get installed.
fish's signal handlers are now sufficiently innocuous that there should
be no reason to block signals (outside of temporarily, when creating a
thread and we need to manipulate the signal mask).
PR #3691 made most calls to `signal_block()` and `signal_unblock()`
no-ops unless a magic env var is set when fish starts running. It's
been seven months since that change was made and no problems have been
reported. This finishes that work by removing those no-op function calls
and support for the magic env var in our next major release (which won't
happen till at least six months from now).
This is the next step in determining whether we can disable blocking
signals without a good reason to do so. This makes not blocking signals
the default behavior. If someone finds a problem they can add this to
their ~/config/fish/config.fish file:
set FISH_NO_SIGNAL_BLOCK 0
Alternatively set that env var before starting fish. I won't be surprised
if people report problems. Till now we have relied on people opting in
to this behavior to tell us whether it causes problems. This makes the
experimental behavior the default that has to be opted out of. This will
give us a lot more confidence this change doesn't cause problems before
the next minor release.
Note that there are still a few places where we force blocking of
signals. Primarily to keep SIGTSTP from interfering with the shell in
response to manipulating the controlling tty. Bash is more selective
in the signals it blocks around the problematic syscalls (c.f., its
`git_terminal_to()` function). However, I don't see any value in that
refinement.
The shell was doing a log of signal blocking/unblocking that hurts
performance and can be avoided. This reduced the elapsed time for a
simple benchmark by 25%.
Partial fix for #2007
Remove the "make iwyu" build target. Move the functionality into the
recently introduced lint.fish script. Fix a lot, but not all, of the
include-what-you-use errors. Specifically, it fixes all of the IWYU errors
on my OS X server but only removes some of them on my Ubuntu 14.04 server.
Fixes#2957
This change moves source files into a src/ directory,
and puts object files into an obj/ directory. The Makefile
and xcode project are updated accordingly.
Fixes#1866
