use the interpreter's import lock instead of threading.RLock in...

use the interpreter's import lock instead of threading.RLock in ERP5Type.dynamic to avoid possible dead lock.
(cherry picked from commit a29456bc)

product/ERP5Type/Base.py

@@ -84,6 +84,7 @@ from Products.ERP5Type.Accessor.TypeDefinition import asDate
 from Products.ERP5Type.Message import Message
 from Products.ERP5Type.ConsistencyMessage import ConsistencyMessage
 from Products.ERP5Type.UnrestrictedMethod import UnrestrictedMethod
+from Products.ERP5Type.dynamic.import_lock import ImportLock
 
 from zope.interface import classImplementsOnly, implementedBy
 
@@ -708,7 +709,7 @@ class Base( CopyContainer,
   isTempDocument = ConstantGetter('isTempDocument', value=False)
 
   # Dynamic method acquisition system (code generation)
-  aq_method_lock = threading.RLock()
+  aq_method_lock = ImportLock()
   aq_method_generated = set()
   aq_method_generating = []
   aq_portal_type = {}

product/ERP5Type/dynamic/dynamic_module.py

@@ -29,7 +29,7 @@
 
 from types import ModuleType
 import sys
-import threading
+from Products.ERP5Type.dynamic.import_lock import ImportLock
 
 class DynamicModule(ModuleType):
   """This module may generate new objects at runtime."""
@@ -41,7 +41,7 @@ class DynamicModule(ModuleType):
   def __init__(self, name, factory, doc=None):
     super(DynamicModule, self).__init__(name, doc=doc)
     self._factory = factory
-    self._lock = threading.RLock()
+    self._lock = ImportLock()
 
   def __getattr__(self, name):
     if name[:2] == '__':

product/ERP5Type/dynamic/import_lock.py

+# -*- coding: utf-8 -*-
+##############################################################################
+# Copyright (c) 2012 Nexedi SA and Contributors. All Rights Reserved.
+#
+# WARNING: This program as such is intended to be used by professional
+# programmers who take the whole responsibility of assessing all potential
+# consequences resulting from its eventual inadequacies and bugs
+# End users who are looking for a ready-to-use solution with commercial
+# guarantees and support are strongly advised to contract a Free Software
+# Service Company
+#
+# This program is Free Software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+##############################################################################
+
+import imp
+class ImportLock(object):
+  """
+  This class provides the interpreter's import lock.
+  It is intended to use in ERP5Type.dynamic to avoid possible dead lock.
+
+  It can be used in two ways :
+
+  1) 'with' statement
+
+  lock = ImportLock()
+  with lock:
+    ...
+
+  2) traditional 'try' and 'finally'
+
+  lock = ImportLock()
+  lock.acquire()
+  try:
+    ...
+  finally:
+    lock.release()
+
+  """
+  def __enter__(self):
+    imp.acquire_lock()
+
+  def __exit__(self, type, value, tb):
+    imp.release_lock()
+
+  def acquire(self):
+    imp.acquire_lock()
+
+  def release(self):
+    imp.release_lock()