Update TimeDelta field type to float for Marshmallow v4

In Marshmallow v3.17.0, up until v4, the `TimeDelta` field could be serialized into either an integer or a float, depending on user specification of the field. [1] In the case the user set `serialization_type=float`, apispec would generate the wrong JSON type in the API docs. With Marshmallow v4, this was removed and `TimeDelta` fields *always* serialize to floats, in which case apispec always generates the wrong docs. This commit updates the default field mapping anticipating Marshmallow v4's float serialization, with some additional support added for <v4 by looking for the deprecated and removed `serialization_type` attribute on the field object. [1] https://marshmallow.readthedocs.io/en/stable/marshmallow.fields.html#marshmallow.fields.TimeDelta

Author: LewisHaley

AUTHORS.rst

@@ -87,3 +87,4 @@ Contributors (chronological)
 - Robert Shepley `@ShepleySound <https://github.com/ShepleySound>`_
 - Robin `@allrob23 <https://github.com/allrob23>`_
 - Xingang Zhang `@0x0400 <https://github.com/0x0400>`_
+- Lewis Haley `@LewisHaley <https://github.com/LewisHaley>`_

src/apispec/ext/marshmallow/field_converter.py

@@ -31,7 +31,7 @@
  marshmallow.fields.DateTime: ("string", "date-time"),
  marshmallow.fields.Date: ("string", "date"),
  marshmallow.fields.Time: ("string", None),
- marshmallow.fields.TimeDelta: ("integer", None),
+ marshmallow.fields.TimeDelta: ("number", None),
  marshmallow.fields.Email: ("string", "email"),
  marshmallow.fields.URL: ("string", "url"),
  marshmallow.fields.Dict: ("object", None),
@@ -538,6 +538,13 @@ def timedelta2properties(self, field, **kwargs: typing.Any) -> dict:
  ret = {}
  if isinstance(field, marshmallow.fields.TimeDelta):
  ret["x-unit"] = field.precision
+ # Required for Marshmallow <4. Can be removed when support for Marshmallow 3 is dropped.
+ # This overrides the type set in field2type_and_format (from DEFAULT_FIELD_MAPPING)
+ if hasattr(field, "serialization_type"):
+ ret["type"] = {
+ int: "integer",
+ float: "number",
+ }.get(field.serialization_type, "number")
  return ret
 
  def enum2properties(self, field, **kwargs: typing.Any) -> dict:

tests/test_ext_marshmallow_field.py

@@ -1,13 +1,17 @@
 import datetime as dt
+import importlib.metadata
 import re
 from enum import Enum
 
 import pytest
 from marshmallow import Schema, fields, validate
+from packaging.version import Version
 
 from .schemas import CategorySchema, CustomIntegerField, CustomList, CustomStringField
 from .utils import build_ref, get_schemas
 
+MA_VERSION = Version(importlib.metadata.version("marshmallow"))
+
 
 def test_field2choices_preserving_order(openapi):
  choices = ["a", "b", "c", "aa", "0", "cc"]
@@ -28,7 +32,7 @@ def test_field2choices_preserving_order(openapi):
  (fields.DateTime, "string"),
  (fields.Date, "string"),
  (fields.Time, "string"),
- (fields.TimeDelta, "integer"),
+ (fields.TimeDelta, "number" if MA_VERSION.major >= 4 else "integer"),
  (fields.Email, "string"),
  (fields.URL, "string"),
  (fields.IP, "string"),
@@ -45,6 +49,26 @@ def test_field2property_type(FieldClass, jsontype, spec_fixture):
  assert res["type"] == jsontype
 
 
+@pytest.mark.skipif(
+ MA_VERSION.major >= 4, reason="Marshmallow 4 removed serialization_type attribute"
+)
+@pytest.mark.parametrize(
+ ("serialization_type", "expected_type"),
+ [
+ (int, "integer"),
+ (float, "number"),
+ ],
+)
+def test_field2property_type_for_timedelta_marshmallow_3(
+ spec_fixture,
+ serialization_type,
+ expected_type,
+):
+ field = fields.TimeDelta(serialization_type=serialization_type)
+ res = spec_fixture.openapi.field2property(field)
+ assert res["type"] == expected_type
+
+
 def test_field2property_no_type(spec_fixture):
  field = fields.Raw()
  res = spec_fixture.openapi.field2property(field)