diff --git a/odoo/addons/base/controllers/rpc.py b/odoo/addons/base/controllers/rpc.py
index 405fd26c44d..930c3170e52 100644
--- a/odoo/addons/base/controllers/rpc.py
+++ b/odoo/addons/base/controllers/rpc.py
@@ -7,6 +7,7 @@ from werkzeug.wrappers import Response
 from odoo.http import Controller, dispatch_rpc, request, route
 from odoo.service import wsgi_server
 from odoo.fields import Date, Datetime
+from odoo.tools import lazy
 
 
 class OdooMarshaller(xmlrpc.client.Marshaller):
@@ -28,6 +29,11 @@ class OdooMarshaller(xmlrpc.client.Marshaller):
         self.dump_unicode(value, write)
     dispatch[date] = dump_date
 
+    def dump_lazy(self, value, write):
+        v = value._value
+        return self.dispatch[type(v)](self, v, write)
+    dispatch[lazy] = dump_lazy
+
 
 # monkey-patch xmlrpc.client's marshaller
 xmlrpc.client.Marshaller = OdooMarshaller
diff --git a/odoo/addons/base/tests/test_xmlrpc.py b/odoo/addons/base/tests/test_xmlrpc.py
index 09ec01adfbb..aa4d9028d10 100644
--- a/odoo/addons/base/tests/test_xmlrpc.py
+++ b/odoo/addons/base/tests/test_xmlrpc.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+import odoo.tools
 from odoo.tests import common
 
 
@@ -25,3 +26,41 @@ class TestXMLRPC(common.HttpCase):
         self.assertIsInstance(ids, list)
         ids = o.execute(db_name, self.admin_uid, 'admin', 'ir.model', 'search', [], {})
         self.assertIsInstance(ids, list)
+
+    def test_xmlrpc_read_group(self):
+        groups = self.xmlrpc_object.execute(
+            common.get_db_name(), self.admin_uid, 'admin',
+            'res.partner', 'read_group', [], ['is_company', 'color'], ['parent_id']
+        )
+
+    def test_xmlrpc_name_search(self):
+        self.xmlrpc_object.execute(
+            common.get_db_name(), self.admin_uid, 'admin',
+            'res.partner', 'name_search', "admin"
+        )
+
+    def test_jsonrpc_read_group(self):
+        self._json_call(
+            common.get_db_name(), self.admin_uid, 'admin',
+            'res.partner', 'read_group', [], ['is_company', 'color'], ['parent_id']
+        )
+
+    def test_jsonrpc_name_search(self):
+        # well that's some sexy sexy call right there
+        self._json_call(
+            common.get_db_name(),
+            self.admin_uid, 'admin',
+            'res.partner', 'name_search', 'admin'
+        )
+
+    def _json_call(self, *args):
+        self.opener.post("http://%s:%s/jsonrpc" % (common.HOST, odoo.tools.config['http_port']), json={
+            'jsonrpc': '2.0',
+            'id': None,
+            'method': 'call',
+            'params': {
+                'service': 'object',
+                'method': 'execute',
+                'args': args
+            }
+        })
diff --git a/odoo/addons/test_performance/tests/test_performance.py b/odoo/addons/test_performance/tests/test_performance.py
index 014cfa60aca..d77ef7c1a21 100644
--- a/odoo/addons/test_performance/tests/test_performance.py
+++ b/odoo/addons/test_performance/tests/test_performance.py
@@ -6,7 +6,7 @@ import json
 
 from odoo.addons.base.tests.common import SavepointCaseWithUserDemo
 from odoo.tests.common import TransactionCase, users, warmup, tagged
-from odoo.tools import mute_logger
+from odoo.tools import mute_logger, json_default
 
 
 class TestPerformance(SavepointCaseWithUserDemo):
@@ -447,7 +447,7 @@ class TestPerformance(SavepointCaseWithUserDemo):
                 self.assertEqual(res['value'], exp['value'])
         # now serialize to json, which should force evaluation
         with self.assertQueryCount(__system__=1, demo=1):
-            json.dumps(result)
+            json.dumps(result, default=json_default)
 
 
 @tagged('bacon_and_eggs')
diff --git a/odoo/service/model.py b/odoo/service/model.py
index 731007abd23..6cc05476195 100644
--- a/odoo/service/model.py
+++ b/odoo/service/model.py
@@ -15,6 +15,7 @@ from odoo.tools.translate import translate, translate_sql_constraint
 from odoo.tools.translate import _
 
 from . import security
+from ..tools import traverse_containers, lazy
 
 _logger = logging.getLogger(__name__)
 
@@ -155,7 +156,12 @@ def execute_cr(cr, uid, obj, method, *args, **kw):
     recs = odoo.api.Environment(cr, uid, {}).get(obj)
     if recs is None:
         raise UserError(_("Object %s doesn't exist") % obj)
-    return odoo.api.call_kw(recs, method, args, kw)
+    result = odoo.api.call_kw(recs, method, args, kw)
+    # force evaluation of lazy values before the cursor is closed, as it would
+    # error afterwards if the lazy isn't already evaluated (and cached)
+    for l in traverse_containers(result, lazy):
+        _0 = l._value
+    return result
 
 
 def execute_kw(db, uid, obj, method, args, kw=None):
diff --git a/odoo/tools/date_utils.py b/odoo/tools/date_utils.py
index c26817b3850..9d934448e30 100644
--- a/odoo/tools/date_utils.py
+++ b/odoo/tools/date_utils.py
@@ -4,8 +4,9 @@ import calendar
 from datetime import date, datetime, time
 import pytz
 from dateutil.relativedelta import relativedelta
-from . import ustr
 
+from . import ustr
+from .func import lazy
 
 def get_month(date):
     ''' Compute the month dates range on which the 'date' parameter belongs to.
@@ -198,16 +199,17 @@ def subtract(value, *args, **kwargs):
     """
     return value - relativedelta(*args, **kwargs)
 
-
 def json_default(obj):
     """
     Properly serializes date and datetime objects.
     """
     from odoo import fields
+    if isinstance(obj, datetime):
+        return fields.Datetime.to_string(obj)
     if isinstance(obj, date):
-        if isinstance(obj, datetime):
-            return fields.Datetime.to_string(obj)
         return fields.Date.to_string(obj)
+    if isinstance(obj, lazy):
+        return obj._value
     return ustr(obj)
 
 
diff --git a/odoo/tools/func.py b/odoo/tools/func.py
index 424b6879aba..deae2bdec04 100644
--- a/odoo/tools/func.py
+++ b/odoo/tools/func.py
@@ -242,14 +242,3 @@ class lazy(object):
     def __aenter__(self): return self._value.__aenter__()
     def __aexit__(self, exc_type, exc_value, traceback):
         return self._value.__aexit__(exc_type, exc_value, traceback)
-
-
-# patch serialization of lazy
-def default(self, o):
-    if isinstance(o, lazy):
-        return o._value
-    return json_encoder_default(self, o)
-
-
-json_encoder_default = JSONEncoder.default
-JSONEncoder.default = default
diff --git a/odoo/tools/misc.py b/odoo/tools/misc.py
index ad599a5d8e5..2e58ad9e012 100644
--- a/odoo/tools/misc.py
+++ b/odoo/tools/misc.py
@@ -1507,3 +1507,21 @@ def get_diff(data_from, data_to, custom_style=False):
         numlines=3,
     )
     return handle_style(diff, custom_style)
+
+
+def traverse_containers(val, type_):
+    """ Yields atoms filtered by specified type_ (or type tuple), traverses
+    through standard containers (non-string mappings or sequences) *unless*
+    they're selected by the type filter
+    """
+    if isinstance(val, type_):
+        yield val
+    elif isinstance(val, (str, bytes)):
+        return
+    elif isinstance(val, Mapping):
+        for k, v in val.items():
+            yield from traverse_containers(k, type_)
+            yield from traverse_containers(v, type_)
+    elif isinstance(val, collections.abc.Sequence):
+        for v in val:
+            yield from traverse_containers(v, type_)