ZODB Components: When executing code, module globals disappeared after a reset...

ZODB Components: When executing code, module globals disappeared after a reset performed in another thread.

This fixes failures in erp5_configurator* tests where BTs installed during the
tests trigger a reset and globals (such as DateTime global import) were reset to
None.

product/ERP5Type/dynamic/component_package.py

@@ -34,6 +34,7 @@ import sys
 import imp
 
 from Products.ERP5.ERP5Site import getSite
+from Products.ERP5Type.Globals import get_request
 from . import aq_method_lock
 from types import ModuleType
 from zLOG import LOG, BLATHER
@@ -369,6 +370,23 @@ class ComponentDynamicPackage(ModuleType):
       if module_fullname_alias:
         setattr(self, name, module)
 
+      # When the reference counter of a module reaches 0, its globals are all
+      # reset to None. So, if a thread performs a reset while another one
+      # executes codes using globals (such as modules imported at module level),
+      # the latter one must keep a reference around to avoid reaching a
+      # reference count to 0. Thus, add it to Request object.
+      #
+      # OTOH, this means that ZODB Components module *must* be imported at the
+      # top level, otherwise a module being relied upon may have a different API
+      # after rset, thus it may fail...
+      request_obj = get_request()
+      module_cache_set = getattr(request_obj, '_module_cache_set', None)
+      if module_cache_set is None:
+        module_cache_set = set()
+        request_obj._module_cache_set = module_cache_set
+
+      module_cache_set.add(module)
+
       return module
     finally:
       # load_module() can be called outside of import machinery, for example