I'm afraid to send this to the distutils
mailing list, because I'm pretty sure I'm making a dumb misinterpretation.
Here is the function _spawn_posix
in distutils
version 2.7.9:
def _spawn_posix(cmd, search_path=1, verbose=0, dry_run=0):
log.info(' '.join(cmd))
if dry_run:
return
executable = cmd[0]
exec_fn = search_path and os.execvp or os.execv
env = None
if sys.platform == 'darwin':
global _cfg_target, _cfg_target_split
if _cfg_target is None:
_cfg_target = sysconfig.get_config_var(
'MACOSX_DEPLOYMENT_TARGET') or ''
if _cfg_target:
_cfg_target_split = [int(x) for x in _cfg_target.split('.')]
if _cfg_target:
# ensure that the deployment target of build process is not less
# than that used when the interpreter was built. This ensures
# extension modules are built with correct compatibility values
cur_target = os.environ.get('MACOSX_DEPLOYMENT_TARGET', _cfg_target)
if _cfg_target_split > [int(x) for x in cur_target.split('.')]:
my_msg = ('$MACOSX_DEPLOYMENT_TARGET mismatch: '
'now "%s" but "%s" during configure'
% (cur_target, _cfg_target))
raise DistutilsPlatformError(my_msg)
env = dict(os.environ,
MACOSX_DEPLOYMENT_TARGET=cur_target)
exec_fn = search_path and os.execvpe or os.execve
pid = os.fork()
if pid == 0: # in the child
try:
if env is None:
exec_fn(executable, cmd)
else:
exec_fn(executable, cmd, env)
except OSError, e:
if not DEBUG:
cmd = executable
sys.stderr.write("unable to execute %r: %s\n" %
(cmd, e.strerror))
os._exit(1)
if not DEBUG:
cmd = executable
sys.stderr.write("unable to execute %r for unknown reasons" % cmd)
os._exit(1)
else: # in the parent
# Loop until the child either exits or is terminated by a signal
# (ie. keep waiting if it's merely stopped)
while 1:
try:
pid, status = os.waitpid(pid, 0)
except OSError, exc:
import errno
if exc.errno == errno.EINTR:
continue
if not DEBUG:
cmd = executable
raise DistutilsExecError, \
"command %r failed: %s" % (cmd, exc[-1])
if os.WIFSIGNALED(status):
if not DEBUG:
cmd = executable
raise DistutilsExecError, \
"command %r terminated by signal %d" % \
(cmd, os.WTERMSIG(status))
elif os.WIFEXITED(status):
exit_status = os.WEXITSTATUS(status)
if exit_status == 0:
return # hey, it succeeded!
else:
if not DEBUG:
cmd = executable
raise DistutilsExecError, \
"command %r failed with exit status %d" % \
(cmd, exit_status)
elif os.WIFSTOPPED(status):
continue
else:
if not DEBUG:
cmd = executable
raise DistutilsExecError, \
"unknown error executing %r: termination status %d" % \
(cmd, status)
Obviously there's a lot there. No one wants to read that. All you need to do is the following:
- Find the line
exec_fn(executable, cmd)
. That's the line this whole function is setup to execute. It callsos.execvp
. - Notice that
exec_fn
is only called whenpid == 0
. Notice that when
pid == 0
, the following code is called:try: if env is None: exec_fn(executable, cmd) else: exec_fn(executable, cmd, env) except OSError, e: if not DEBUG: cmd = executable sys.stderr.write("unable to execute %r: %s\n" % (cmd, e.strerror)) os._exit(1) if not DEBUG: cmd = executable sys.stderr.write("unable to execute %r for unknown reasons" % cmd) os._exit(1)
Notice here that if an
OSError
is raised in thetry
block, we exit to the system with a status of 1 (failure).- Notice that even if an
OSError
is not raised, we still exit to the system with a status of 1 (failure). - In both cases, the parent process, which has been waiting for the child to finish, raises a
DistutilsExecError
.
Can someone point out my error? Or do I happen to be using the version of distutils
with a crazy bug that has since been fixed?