Nicer error when packing a datetime without tzinfo

Author: begelundmuller

msgpack/_packer.pyx

@@ -274,7 +274,9 @@ cdef class Packer(object):
                 if ret == 0:
                     ret = msgpack_pack_raw_body(&self.pk, <char*>view.buf, L)
                 PyBuffer_Release(&view);
-            elif self.datetime and PyDateTime_CheckExact(o) and datetime_tzinfo(o) is not None:
+            elif self.datetime and PyDateTime_CheckExact(o):
+                if datetime_tzinfo(o) is None:
+                    PyErr_Format(ValueError, b"can not serialize '%.200s' object where tzinfo=None", Py_TYPE(o).tp_name)
                 delta = o - epoch
                 if not PyDelta_CheckExact(delta):
                     raise ValueError("failed to calculate delta")

msgpack/fallback.py

@@ -865,7 +865,9 @@ def _pack(
                     len(obj), dict_iteritems(obj), nest_limit - 1
                 )
 
-            if self._datetime and check(obj, _DateTime) and obj.tzinfo is not None:
+            if self._datetime and check(obj, _DateTime):
+                if obj.tzinfo is None:
+                    raise ValueError("Cannot serialize %r where tzinfo=None" % (obj,))
                 obj = Timestamp.from_datetime(obj)
                 default_used = 1
                 continue

test/test_timestamp.py

@@ -140,3 +140,14 @@ def test_issue451():
 
     unpacked = msgpack.unpackb(packed, timestamp=3)
     assert dt == unpacked
+
+@pytest.mark.skipif(sys.version_info[0] == 2, reason="datetime support is PY3+ only")
+def test_pack_datetime_without_tzinfo():
+    dt = datetime.datetime(1970, 1, 1, 0, 0, 42, 14)
+    with pytest.raises(ValueError, match="where tzinfo=None"):
+        packed = msgpack.packb(dt, datetime=True)
+
+    dt = datetime.datetime(1970, 1, 1, 0, 0, 42, 14, tzinfo=_utc)
+    packed = msgpack.packb(dt, datetime=True)
+    unpacked = msgpack.unpackb(packed, timestamp=3)
+    assert unpacked == dt