Nicer error when packing a datetime without tzinfo (#466)

2 files changed, 6 insertions, 0 deletions

diff --git a/msgpack/_packer.pyx b/msgpack/_packer.pyx
index e6cd2c7..396da0c 100644
--- a/msgpack/_packer.pyx
+++ b/msgpack/_packer.pyx
@@ -285,6 +285,8 @@ cdef class Packer(object):
                 o = self._default(o)
                 default_used = 1
                 continue
+            elif self.datetime and PyDateTime_CheckExact(o):
+                PyErr_Format(ValueError, b"can not serialize '%.200s' object where tzinfo=None", Py_TYPE(o).tp_name)
             else:
                 PyErr_Format(TypeError, b"can not serialize '%.200s' object", Py_TYPE(o).tp_name)
             return ret
diff --git a/msgpack/fallback.py b/msgpack/fallback.py
index 4540875..b27acb2 100644
--- a/msgpack/fallback.py
+++ b/msgpack/fallback.py
@@ -874,6 +874,10 @@ class Packer(object):
                 obj = self._default(obj)
                 default_used = 1
                 continue
+
+            if self._datetime and check(obj, _DateTime):
+                raise ValueError("Cannot serialize %r where tzinfo=None" % (obj,))
+
             raise TypeError("Cannot serialize %r" % (obj,))
 
     def pack(self, obj):