# HG changeset patch
# User Jun Wu <quark@fb.com>
# Date 2016-07-28 19:57:07
# Node ID 7bc25549e0844de71eb16610d33f8e6adaca097b
# Parent  47de34f79f93c11aa63bfc4646e3283483d174a9

worker: allow waitforworkers to be non-blocking

This patch adds a boolean flag to waitforworkers and makes it non-blocking
if set to True.

This is to make it possible that we can reap our workers while keep other
unrelated children untouched, after receiving SIGCHLD.

diff --git a/mercurial/worker.py b/mercurial/worker.py
--- a/mercurial/worker.py
+++ b/mercurial/worker.py
@@ -97,9 +97,11 @@ def _posixworker(ui, func, staticargs, a
             except OSError as err:
                 if err.errno != errno.ESRCH:
                     raise
-    def waitforworkers():
+    def waitforworkers(blocking=True):
         for pid in pids:
-            st = _exitstatus(os.waitpid(pid, 0)[1])
+            p, st = os.waitpid(pid, 0 if blocking else os.WNOHANG)
+            if p:
+                st = _exitstatus(st)
             if st and not problem[0]:
                 problem[0] = st
                 killworkers()