Restore rev 47014:

The hppa ubuntu box sometimes hangs forever in these tests.  My guess
is that the wait is failing for some reason.  Use WNOHANG, so we won't
wait until the buildbot kills the test suite.

I haven't been able to reproduce the failure, so I'm not sure if
this will help or not.  Hopefully, this change will cause the test
to fail, rather than hang.  That will be better since we will get
the rest of the test results.  It may also help us debug the real problem.

*** The reason this originally failed was because there were many
zombie children outstanding before rev 47158 cleaned them up.
There are still hangs in test_subprocess that need to be addressed,
but that will take more work.  This should close some holes.

4 files changed, 32 insertions, 5 deletions

diff --git a/Lib/test/fork_wait.py b/Lib/test/fork_wait.py
index 5600bdb..7eb55f6 100644
--- a/Lib/test/fork_wait.py
+++ b/Lib/test/fork_wait.py
@@ -34,7 +34,14 @@ class ForkWait(unittest.TestCase):
                 pass
 
     def wait_impl(self, cpid):
-        spid, status = os.waitpid(cpid, 0)
+        for i in range(10):
+            # waitpid() shouldn't hang, but some of the buildbots seem to hang
+            # in the forking tests.  This is an attempt to fix the problem.
+            spid, status = os.waitpid(cpid, os.WNOHANG)
+            if spid == cpid:
+                break
+            time.sleep(2 * SHORTSLEEP)
+
         self.assertEquals(spid, cpid)
         self.assertEquals(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))
 
diff --git a/Lib/test/test_fork1.py b/Lib/test/test_fork1.py
index e909844..e64e398 100644
--- a/Lib/test/test_fork1.py
+++ b/Lib/test/test_fork1.py
@@ -2,6 +2,7 @@
 """
 
 import os
+import time
 from test.fork_wait import ForkWait
 from test.test_support import TestSkipped, run_unittest, reap_children
 
@@ -12,7 +13,14 @@ except AttributeError:
 
 class ForkTest(ForkWait):
     def wait_impl(self, cpid):
-        spid, status = os.waitpid(cpid, 0)
+        for i in range(10):
+            # waitpid() shouldn't hang, but some of the buildbots seem to hang
+            # in the forking tests.  This is an attempt to fix the problem.
+            spid, status = os.waitpid(cpid, os.WNOHANG)
+            if spid == cpid:
+                break
+            time.sleep(1.0)
+
         self.assertEqual(spid, cpid)
         self.assertEqual(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))
 
diff --git a/Lib/test/test_wait3.py b/Lib/test/test_wait3.py
index 8279973..9de64b2 100644
--- a/Lib/test/test_wait3.py
+++ b/Lib/test/test_wait3.py
@@ -2,6 +2,7 @@
 """
 
 import os
+import time
 from test.fork_wait import ForkWait
 from test.test_support import TestSkipped, run_unittest, reap_children
 
@@ -17,10 +18,14 @@ except AttributeError:
 
 class Wait3Test(ForkWait):
     def wait_impl(self, cpid):
-        while 1:
-            spid, status, rusage = os.wait3(0)
+        for i in range(10):
+            # wait3() shouldn't hang, but some of the buildbots seem to hang
+            # in the forking tests.  This is an attempt to fix the problem.
+            spid, status, rusage = os.wait3(os.WNOHANG)
             if spid == cpid:
                 break
+            time.sleep(1.0)
+
         self.assertEqual(spid, cpid)
         self.assertEqual(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))
         self.assertTrue(rusage)
diff --git a/Lib/test/test_wait4.py b/Lib/test/test_wait4.py
index 711fd2d..9f7fc14 100644
--- a/Lib/test/test_wait4.py
+++ b/Lib/test/test_wait4.py
@@ -2,6 +2,7 @@
 """
 
 import os
+import time
 from test.fork_wait import ForkWait
 from test.test_support import TestSkipped, run_unittest, reap_children
 
@@ -17,7 +18,13 @@ except AttributeError:
 
 class Wait4Test(ForkWait):
     def wait_impl(self, cpid):
-        spid, status, rusage = os.wait4(cpid, 0)
+        for i in range(10):
+            # wait4() shouldn't hang, but some of the buildbots seem to hang
+            # in the forking tests.  This is an attempt to fix the problem.
+            spid, status, rusage = os.wait4(cpid, os.WNOHANG)
+            if spid == cpid:
+                break
+            time.sleep(1.0)
         self.assertEqual(spid, cpid)
         self.assertEqual(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))
         self.assertTrue(rusage)