[pypy-commit] pypy release-pypy3.6-v7.x: merge py3.6 into release

[mattip]

Author: Matti Picus <matti.picus at gmail.com>
Branch: release-pypy3.6-v7.x
Changeset: r98266:533398cfd64e
Date: 2019-12-10 18:46 +0200
http://bitbucket.org/pypy/pypy/changeset/533398cfd64e/

Log:	merge py3.6 into release

diff --git a/lib-python/3/importlib/_bootstrap.py b/lib-python/3/importlib/_bootstrap.py
--- a/lib-python/3/importlib/_bootstrap.py
+++ b/lib-python/3/importlib/_bootstrap.py
@@ -67,6 +67,7 @@
         # Deadlock avoidance for concurrent circular imports.
         me = _thread.get_ident()
         tid = self.owner
+        count = 0
         while True:
             lock = _blocking_on.get(tid)
             if lock is None:
@@ -74,6 +75,14 @@
             tid = lock.owner
             if tid == me:
                 return True
+            # workaround for https://bugs.python.org/issue38091:
+            # instead of looping here forever, eventually return False.
+            # Unsure if this will cause real deadlocks to go undetected,
+            # but at least it doesn't cause *this* logic here to
+            # deadlock when there is otherwise no deadlock!
+            count += 1
+            if count >= 100:
+                return False
 
     def acquire(self):
         """
diff --git a/lib-python/3/test/test_import/__init__.py b/lib-python/3/test/test_import/__init__.py
--- a/lib-python/3/test/test_import/__init__.py
+++ b/lib-python/3/test/test_import/__init__.py
@@ -366,16 +366,22 @@
                 os.does_not_exist
 
     def test_concurrency(self):
+        def delay_has_deadlock(frame, event, arg):
+            if event == 'call' and frame.f_code.co_name == 'has_deadlock':
+                time.sleep(0.05)
+
         sys.path.insert(0, os.path.join(os.path.dirname(__file__), 'data'))
         try:
             exc = None
             def run():
+                sys.settrace(delay_has_deadlock)
                 event.wait()
                 try:
                     import package
                 except BaseException as e:
                     nonlocal exc
                     exc = e
+                sys.settrace(None)
 
             for i in range(10):
                 event = threading.Event()