[FIX] base: always preload dateutil

The dateutil package uses lazy import to selectively expose its
features: `parser`, `relativedelta`, `rrule`, `tz`.

Depending on installed modules and order of initialization, there was no
guarantee that a given feature was already loaded during the preparation
of the action context.

This patch ensures that we always preload the feature set we need, and
only that feature set. This way we have a consistent `dateutil` lib in
the action context at all times.

openerp/addons/base/ir/ir_actions.py

@@ -7,7 +7,6 @@ import operator
 import os
 import time
 import datetime
-import dateutil
 import pytz
 
 import openerp
@@ -19,7 +18,7 @@ from openerp.osv import fields, osv
 from openerp.osv.orm import browse_record
 import openerp.report.interface
 from openerp.report.report_sxw import report_sxw, report_rml
-from openerp.tools import ormcache
+from openerp.tools import ormcache, wrap_module
 from openerp.tools.safe_eval import safe_eval as eval
 from openerp.tools.translate import _
 import openerp.workflow
@@ -28,6 +27,16 @@ from openerp.exceptions import MissingError, UserError
 _logger = logging.getLogger(__name__)
 
 
+# build dateutil helper, starting with the relevant *lazy* imports
+import dateutil
+import dateutil.parser
+import dateutil.relativedelta
+import dateutil.rrule
+import dateutil.tz
+mods = {'parser', 'relativedelta', 'rrule', 'tz'}
+attribs = {atr for m in mods for atr in getattr(dateutil, m).__all__}
+dateutil = wrap_module(dateutil, mods | attribs)
+
 class actions(osv.osv):
     _name = 'ir.actions.actions'
     _table = 'ir_actions'

openerp/tools/misc.py

@@ -19,6 +19,7 @@ import socket
 import sys
 import threading
 import time
+import types
 import werkzeug.utils
 import zipfile
 from cStringIO import StringIO
@@ -1234,3 +1235,23 @@ class Pickle(object):
     dump = cPickle.dump
 
 pickle = Pickle
+
+def wrap_module(module, attr_list):
+    """Helper for wrapping a package/module to expose selected attributes
+
+       :param Module module: the actual package/module to wrap, as returned by ``import <module>``
+       :param iterable attr_list: a global list of attributes to expose, usually the top-level
+            attributes and their own main attributes. No support for hiding attributes in case
+            of name collision at different levels.
+    """
+    attr_list = set(attr_list)
+    class WrappedModule(object):
+        def __getattr__(self, attrib):
+            if attrib in attr_list:
+                target = getattr(module, attrib)
+                if isinstance(target, types.ModuleType):
+                    return wrap_module(target, attr_list)
+                return target
+            raise AttributeError(attrib)
+    # module and attr_list are in the closure
+    return WrappedModule()