ConnectEx will let us restore non-blocking behavior on connect. Also
revisiting our IOCP implementation to see if we can do other
refactoring, such as removing code that tries to user OVERLAPPED
internals for no good reason.
For unclosable files, no need to dup, but for closable files we can get
a resource leak. Valgrind and similar tools won't catch this but IO will
unexpectedly start going to the wrong descriptor if a file was
transferred to a new thread, closed, and then a new file was created.
janet_collect() marks janet_vm.root_fiber but not janet_vm.fiber.
When janet_pcall (or janet_continue) is called from a C function,
the inner fiber becomes janet_vm.fiber while root_fiber still points
to the outer fiber. If GC triggers inside the inner fiber's execution,
the inner fiber is not in any GC root set and can be collected —
including its stack memory — while actively running.
This also affects deeply nested cases: F1 -> C func -> janet_pcall ->
F2 -> C func -> janet_pcall -> F3, where F2 is saved only in a C
stack local (tstate.vm_fiber), invisible to GC.
Fix: in janet_continue_no_check, root the fiber with janet_gcroot
when this is a nested call (root_fiber already set). Each nesting
level roots its own fiber, handling arbitrary depth. Top-level calls
(event loop, REPL) skip the root/unroot entirely since root_fiber
is NULL.
Add test/test-gc-pcall.c: standalone C test covering both single
and deep nesting cases.
Co-authored-by: Brett Adams <brett@bletia-9.local>
Objects in channels are sent as messages that need to be freed by the
consumer. However, in certain cases, no consumer is available and the
messages were being discarded without properly being freed. This should
also fix `-fsanitize=address` on GCC and CLANG with the default test
suite.
for abstract types.
Abstract types whose get/put/length/etc. implementations allocated fiber
slots could break the VM by invalidating the stack pointer in the
interpreter. This is admittedly a bit unusual but is something most
users would probably expect to work. Debugging this would be a real pain.
For remote connections, if you did not manually wait for the connection
to settle, the programmer would see unspecified network errors. This is
is because the underlying TCP Connection had not been established yet.
The correct way to deal with this is to use ConnectEx if available
instead of WSAConnect.
This was exposed when printing `(invert (range 200000))`, which
isn't so large that we shouldn't be able to sort it, but was taking
far too long to compute.
