Fix duration format overflow handling

jsonschema/_format.py

@@ -3,6 +3,7 @@
 from contextlib import suppress
 from datetime import date, datetime
 from uuid import UUID
+import decimal
 import ipaddress
 import re
 import string
@@ -518,7 +519,10 @@ def is_uri_template(instance: object) -> bool:
     @_checks_drafts(
         draft201909="duration",
         draft202012="duration",
-        raises=isoduration.DurationParsingException,
+        raises=(
+            isoduration.DurationParsingException,
+            decimal.DecimalException,
+        ),
     )
     def is_duration(instance: object) -> bool:
         if not isinstance(instance, str):

jsonschema/tests/test_format.py

@@ -80,6 +80,14 @@ def test_format_checkers_come_with_defaults(self):
         with self.assertRaises(FormatError):
             checker.check(instance="not-an-ipv4", format="ipv4")
 
+    def test_duration_overflow_is_invalid(self):
+        checker = FormatChecker()
+        if "duration" not in checker.checkers:
+            self.skipTest("isoduration is not installed")
+
+        with self.assertRaises(FormatError):
+            checker.check(instance="P1E1000000D", format="duration")
+
     def test_repr(self):
         checker = FormatChecker(formats=())
         checker.checks("foo")(lambda thing: True)  # pragma: no cover