Fix multipleOf crashing on Decimal instances and large integers

jsonschema/_keywords.py

@@ -169,15 +169,17 @@ def multipleOf(validator, dB, instance, schema):
         return
 
     if isinstance(dB, float):
-        quotient = instance / dB
         try:
+            quotient = instance / dB
             failed = int(quotient) != quotient
-        except OverflowError:
-            # When `instance` is large and `dB` is less than one,
-            # quotient can overflow to infinity; and then casting to int
-            # raises an error.
+        except (OverflowError, TypeError):
+            # When `instance` is large and `dB` is less than one, the
+            # quotient can overflow to infinity (or dividing a huge integer
+            # can overflow outright), and then casting to int raises an
+            # OverflowError; and a `Decimal` instance cannot be divided by a
+            # float `dB` at all, which raises a TypeError.
             #
-            # In this case we fall back to Fraction logic, which is
+            # In either case we fall back to Fraction logic, which is
             # exact and cannot overflow.  The performance is also
             # acceptable: we try the fast all-float option first, and
             # we know that fraction(dB) can have at most a few hundred

jsonschema/tests/test_validators.py

@@ -816,6 +816,29 @@ def test_heterogeneous_properties_unevaluatedProperties(self):
         )
 
 
+class TestMultipleOf(TestCase):
+    def test_it_does_not_crash_on_decimals_or_large_integers(self):
+        # ``multipleOf`` with a float divisor divides the instance by the
+        # divisor. The division used to sit outside the guard that only
+        # caught OverflowError, so a Decimal instance raised TypeError
+        # (Decimal / float) and a very large integer raised OverflowError at
+        # the division itself, instead of validating.
+        Validator = validators.Draft202012Validator
+
+        # Both of these are valid (10.0 is a multiple of 2.5, and every
+        # integer is a multiple of 0.5) and must not raise.
+        Validator({"multipleOf": 2.5}).validate(Decimal("10.0"))
+        Validator({"multipleOf": 0.5}).validate(10**400)
+
+        # The Fraction fallback still rejects genuine non-multiples.
+        self.assertFalse(
+            Validator({"multipleOf": 3.3}).is_valid(Decimal(10)),
+        )
+        self.assertFalse(
+            Validator({"multipleOf": 0.3}).is_valid(10**400),
+        )
+
+
 class TestValidationErrorDetails(TestCase):
     # TODO: These really need unit tests for each individual keyword, rather
     #       than just these higher level tests.