##// END OF EJS Templates
worker: rewrite error handling so os._exit covers all cases...
worker: rewrite error handling so os._exit covers all cases Previously the worker error handling is like: pid = os.fork() --+ if pid == 0: | .... | problematic .... --+ try: --+ .... | worker error handling --+ If a signal arrives when Python is executing the "problematic" lines, an external error handling (dispatch.py) will take over the control flow and it's no longer guaranteed "os._exit" is called (see 86cd09bc13ba for why it is necessary). This patch rewrites the error handling so it covers all possible code paths for a worker even during fork. Note: "os.getpid() == parentpid" is used to test if the process is parent or not intentionally, instead of checking "pid", because "pid = os.fork()" may be not atomic - it's possible that that a signal hits the worker before the assignment completes [1]. The newly added test replaces "os.fork" to exercise that extreme case. [1]: CPython compiles "pid = os.fork()" to 2 byte codes: "CALL_FUNCTION" and "STORE_FAST", so it's probably not atomic: def f(): pid = os.fork() dis.dis(f) 2 0 LOAD_GLOBAL 0 (os) 3 LOAD_ATTR 1 (fork) 6 CALL_FUNCTION 0 9 STORE_FAST 0 (pid) 12 LOAD_CONST 0 (None) 15 RETURN_VALUE

File last commit:

r32112:31763785 default
r32112:31763785 default
Show More
test-worker.t
126 lines | 3.0 KiB | text/troff | Tads3Lexer
Test UI worker interaction
$ cat > t.py <<EOF
> from __future__ import absolute_import, print_function
> from mercurial import (
> cmdutil,
> error,
> ui as uimod,
> worker,
> )
> def abort(ui, args):
> if args[0] == 0:
> # by first worker for test stability
> raise error.Abort('known exception')
> return runme(ui, [])
> def exc(ui, args):
> if args[0] == 0:
> # by first worker for test stability
> raise Exception('unknown exception')
> return runme(ui, [])
> def runme(ui, args):
> for arg in args:
> ui.status('run\n')
> yield 1, arg
> functable = {
> 'abort': abort,
> 'exc': exc,
> 'runme': runme,
> }
> cmdtable = {}
> command = cmdutil.command(cmdtable)
> @command('test', [], 'hg test [COST] [FUNC]')
> def t(ui, repo, cost=1.0, func='runme'):
> cost = float(cost)
> func = functable[func]
> ui.status('start\n')
> runs = worker.worker(ui, cost, func, (ui,), range(8))
> for n, i in runs:
> pass
> ui.status('done\n')
> EOF
$ abspath=`pwd`/t.py
$ hg init
Run tests with worker enable by forcing a heigh cost
$ hg --config "extensions.t=$abspath" test 100000.0
start
run
run
run
run
run
run
run
run
done
Run tests without worker by forcing a low cost
$ hg --config "extensions.t=$abspath" test 0.0000001
start
run
run
run
run
run
run
run
run
done
#if no-windows
Known exception should be caught, but printed if --traceback is enabled
$ hg --config "extensions.t=$abspath" --config 'worker.numcpus=2' \
> test 100000.0 abort
start
abort: known exception
[255]
$ hg --config "extensions.t=$abspath" --config 'worker.numcpus=2' \
> test 100000.0 abort --traceback 2>&1 | grep '^Traceback'
Traceback (most recent call last):
Traceback (most recent call last):
Traceback must be printed for unknown exceptions
$ hg --config "extensions.t=$abspath" --config 'worker.numcpus=2' \
> test 100000.0 exc 2>&1 | grep '^Traceback'
Traceback (most recent call last):
Workers should not do cleanups in all cases
$ cat > $TESTTMP/detectcleanup.py <<EOF
> from __future__ import absolute_import
> import atexit
> import os
> import time
> oldfork = os.fork
> count = 0
> parentpid = os.getpid()
> def delayedfork():
> global count
> count += 1
> pid = oldfork()
> # make it easier to test SIGTERM hitting other workers when they have
> # not set up error handling yet.
> if count > 1 and pid == 0:
> time.sleep(0.1)
> return pid
> os.fork = delayedfork
> def cleanup():
> if os.getpid() != parentpid:
> os.write(1, 'should never happen\n')
> atexit.register(cleanup)
> EOF
$ hg --config "extensions.t=$abspath" --config worker.numcpus=8 --config \
> "extensions.d=$TESTTMP/detectcleanup.py" test 100000 abort
start
abort: known exception
[255]
#endif