This merges a sequence of commits that undoes the SIGCONT orchestration
used for WSL compatibility. The essential problem is this: In Unix and
Linux, exited processes are still valid until it is reaped; you can, say,
make an exited process a group leader. But in Windows, when a process
exits, it is gone, and most syscalls (other than, say, waitpid) fail for
it. This is known as the WSL Rick Grimes problem.
This manifests as various race conditions in WSL between a parent operating
on a child, and the child exiting. Prior to this merge, these were
addressed by having the child wait for the parent to send it a SIGCONT.
This resolved the race.
This merge removes this approach and replaces it with a simpler mechanism
that leverages the existing keepalive machinery. A keepalive process is
created for all platforms when we have a pipeline that contains a builtin.
This is necessary to keep the whole process group alive. The fix is, on
WSL, we always create a keepalive and make it the group leader. Because the
keepalive does not call exec and its lifetime is bound to a C++ stack
frame, it is easy to resolve the race.
This improves performance a bit (except on WSL), since child processes no
longer have to synchronize with the parent process, but the big win is
simplicity. This removes the notion of the single global stopped child, of
which there could only be one, and which had be resumed at the right
time(s), of which there were several.
keepalive processes are typically killed by the main shell process.
However if the main shell exits the keepalive may linger. In WSL
keepalives are used more often, and the lingering keepalives are both
leaks and prevent the tests from finishing.
Have keepalives poll for their parent process ID and exit when it
changes, so they can clean themselves up. The polling frequency can be
low.
Have WSL use a keepalive whenever the first process is external.
This works around the fact that WSL prohibits setting an exited
process as the group leader.
* 🚀
* prepare to merge into fish-shell
* split into different files
* remove deprecated option
* captitalize descriptions
* make shorter description for ansible
* update ansible-playbook (and ansible for consistency)
* update version on vault and galaxy
When the pager wants to use the full screen to show many options, it reserves
space at the top to see the command. Previously it pretended the command was a
prompt and engaged the prompt layout mechanism to compute these lines. Instead
let's juts count newlines since escape sequences within commands are very rare.
There were several issues with the way that the include tests for curses.h
were being done that were ultimately causing fish to use the headers from
ncurses but link against curses on platforms that provide an actual
libcurses.so that isn't just a symlink to libncurses.so
In particular, the old code was first testing for curses's cureses.h and then
falling back to libncurses's implementation of the same - but that logic was
reversed when it came to including term.h, in which case it was testing for
the ncurses term.h and falling back to the curses.h header. Long story short,
while cmake will link against libcurses.so if both libcurses.so and
libncurses.so are present (unless CURSES_NEED_NCURSES evaluates to TRUE, but
that makes ncurses a hard requirement), but we were brining in some of the
defines from the ncurses headers, causing SIGSEGV panics when fish ultimately
tried to access variables that weren't exported or were mapped to undefined
areas of memory in the other library.
Additionally it is an error to include termios.h prior to including the plain
Jane curses.h (not ncurses/curses.h), causing errors about unimplemented types
SGTTY/chtype. So far as I can tell, both curses.h and ncurses/curses.h pull in
termios.h themselves so it shouldn't even be necessary to manually include it,
but I have just moved its #include below that of curses.h
The non-ncurses version of term.h requires that curses.h be first
included. Only very recent versions of CMake include a LANGUAGE
option to CHECK_INCLUDE_FILES, so we aren't using it and specifying
CXX here..
This never worked properly (since a branch that only exists locally
would also be offered) and is dog-slow.
When we come up with a better way to do it we can readd it.
When git prints a path like "share/completions/git.fish", that's
relative to the root of the repo. So we need to either remove
everything from the $PWD (if the path is inside the $PWD), or prepend
a ":/", which is git-speak for "relative to the root".
This was removed by mistake in the recent switch to `git status`.
Fixes#4688.
This special cases expansion of $history variables, so that slicing
history no longer needs to construct the entire history array. Speedup
is around 100x in my test.
Fixes#4650
Prior to this fix, if the user typed normal characters while the
completion pager was shown, it would begin searching. This feature was
not well liked, so we are going to instead just append the characters as
normal and disable paging. Control-S can be used to toggle the search
field.
Fixes#2249
CheckFunctionExists checks for C linkage only, and recommends the use of
CheckSymbolExists in the documentation. This improves the detection of
C++ features, as opposed to C features.
