It turns out that the code generation for "with gil" is a bit more
complicated than the logic for re-obtaining the gil at the end of
"with nogil." This is because PyGILState_Ensure seems to, during
interpreter finalization, think it needs to call a new thread
(resulting in a call to cpython new_threadstate) which then segfaults.
Because "with nogil" knows that, prior to executing, it already had
the gil, it doesn't need to set up as much state, and thus the segfault
does not occur.
To avoid this, we just only use "with nogil" within the infinite loop,
and then end the "nogil" block before we check signals. This avoids
needing any "with gil" call at all.
I was able to reliably reproduce the segfault within a few minutes
before the patch by running a binary in a loop (with py3) while
maxing out my machines cpu usage. After the patch, I have not
been able to reproduce the segfault after two hours.
Note that this race can only occur when the user does not properly
clean up all their channels, and is relying on garbage collection to
do so (which isn't guaranteed). However, we want to avoid a segfault
on failure to close because this isn't a good user error and makes it
hard to debug.
Context detail messages are Unicode strings in both the implementation and
specification. Fix the documentation to make this clearer. The
specification for the Status-Message response field says "Status-Message is
[...] a Unicode string [...] encoded as UTF-8" [1]. The implementation
seems to call _common.encode(), so anything that is UTF-8 encodable works.
For example:
context.set_code(grpc.StatusCode.ABORTED)
context.set_details('emoji error: \U0001F600')
Correctly returns a smiley face emoji to the client.
GCC allows this, but notably clang does not. Other systems,
like FreeBSD and some Linux distros ship with clang as default
compiler. While here, switch the approach to filtering out std
flag since the make workaround relies on GNU make syntax and
'make' binary could be bmake and/or gmake could be absent.
The idea to filter the flags was taken from an answer to this
Stack Overflow question:
https://stackoverflow.com/questions/15527611/how-do-i-specify-different-compiler-flags-in-distutils-for-just-one-python-c-ext
Lidi Zheng