Serialize nan and infinities to string

airflow-core/src/airflow/serialization/serialized_objects.py

@@ -25,6 +25,7 @@
 import enum
 import itertools
 import logging
+import math
 import weakref
 from collections.abc import Collection, Generator, Iterable, Iterator, Mapping, Sequence
 from functools import cache, cached_property
@@ -720,6 +721,9 @@ def serialize(
             # enum.IntEnum is an int instance, it causes json dumps error so we use its value.
             if isinstance(var, enum.Enum):
                 return var.value
+            # These are not allowed in JSON. https://datatracker.ietf.org/doc/html/rfc8259#section-6
+            if isinstance(var, float) and (math.isnan(var) or math.isinf(var)):
+                return str(var)
             return var
         elif isinstance(var, dict):
             return cls._encode(

airflow-core/tests/unit/serialization/test_serialized_objects.py

@@ -18,6 +18,7 @@
 from __future__ import annotations
 
 import json
+import math
 from collections.abc import Iterator
 from datetime import datetime, timedelta
 
@@ -254,6 +255,9 @@ def __len__(self) -> int:
     [
         ("test_str", None, equals),
         (1, None, equals),
+        (math.nan, None, lambda a, b: b == "nan"),
+        (math.inf, None, lambda a, b: b == "inf"),
+        (-math.inf, None, lambda a, b: b == "-inf"),
         (timezone.utcnow(), DAT.DATETIME, equal_time),
         (timedelta(minutes=2), DAT.TIMEDELTA, equals),
         (Timezone("UTC"), DAT.TIMEZONE, lambda a, b: a.name == b.name),