Fix conversion of datetimes in TransferData

changelog.d/20260227_094736_sirosen_bugfix_datetime_conversions.rst

@@ -0,0 +1,6 @@
+Fixed
+-----
+
+- Fixed a bug in ``globus_sdk.TransferData`` which failed to convert
+  ``deadline`` to a string when a ``datetime.datetime`` object is given.
+  (:pr:`NUMBER`)

src/globus_sdk/services/transfer/data/transfer_data.py

@@ -5,6 +5,7 @@
 import typing as t
 import uuid
 
+from globus_sdk._internal.remarshal import stringify
 from globus_sdk._missing import MISSING, MissingType
 from globus_sdk._payload import GlobusPayload
 
@@ -176,7 +177,7 @@ def __init__(
         self["destination_endpoint"] = destination_endpoint
         self["label"] = label
         self["submission_id"] = submission_id
-        self["deadline"] = deadline
+        self["deadline"] = stringify(deadline)
         self["source_local_user"] = source_local_user
         self["destination_local_user"] = destination_local_user
         self["verify_checksum"] = verify_checksum

tests/unit/helpers/test_transfer.py

@@ -1,3 +1,5 @@
+import datetime
+
 import pytest
 
 from globus_sdk import MISSING, DeleteData, TransferData
@@ -298,3 +300,17 @@ def test_add_filter_rule():
 )
 def test_ls_format_filter(filter, expected):
     assert _format_filter(filter) == expected
+
+
+@pytest.mark.parametrize(
+    "deadline_str",
+    [
+        pytest.param("2026-02-27 09:36:50.517299", id="naive_w_microseconds"),
+        pytest.param("2020-01-01 08:22:12+04:00", id="plus4"),
+    ],
+)
+def test_transfer_data_stringifies_deadline(deadline_str):
+    deadline_dt = datetime.datetime.fromisoformat(deadline_str)
+
+    tdata = TransferData(GO_EP1_ID, GO_EP2_ID, deadline=deadline_dt)
+    assert tdata["deadline"] == deadline_str