From 46db62a373ccc3d75fefd36f97a5fa8fcafedac4 Mon Sep 17 00:00:00 2001
From: Zac-HD <zac.hatfield.dodds@gmail.com>
Date: Mon, 5 Oct 2020 10:35:10 +1100
Subject: [PATCH] Handle multipleOf overflow

---
 jsonschema/_validators.py                     | 14 ++++++-
 .../tests/test_jsonschema_test_suite.py       | 39 -------------------
 2 files changed, 13 insertions(+), 40 deletions(-)

diff --git a/jsonschema/_validators.py b/jsonschema/_validators.py
index d7097ffbb..7e8c95a4e 100644
--- a/jsonschema/_validators.py
+++ b/jsonschema/_validators.py
@@ -1,3 +1,4 @@
+from fractions import Fraction
 import re
 
 from jsonschema._utils import (
@@ -166,7 +167,18 @@ def multipleOf(validator, dB, instance, schema):
 
     if isinstance(dB, float):
         quotient = instance / dB
-        failed = int(quotient) != quotient
+        try:
+            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.
+            #
+            # In this 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 digits in each part.  The worst-case slowdown
+            # is therefore for already-slow enormous integers or Decimals.
+            failed = (Fraction(instance) / Fraction(dB)).denominator != 1
     else:
         failed = instance % dB
 
diff --git a/jsonschema/tests/test_jsonschema_test_suite.py b/jsonschema/tests/test_jsonschema_test_suite.py
index d6721b597..0f9698a64 100644
--- a/jsonschema/tests/test_jsonschema_test_suite.py
+++ b/jsonschema/tests/test_jsonschema_test_suite.py
@@ -161,7 +161,6 @@ def missing_date_fromisoformat(test):
     DRAFT4.tests(),
     DRAFT4.format_tests(),
     DRAFT4.optional_tests_of(name="bignum"),
-    DRAFT4.optional_tests_of(name="float-overflow"),
     DRAFT4.optional_tests_of(name="non-bmp-regex"),
     DRAFT4.optional_tests_of(name="zeroTerminatedFloats"),
     Validator=Draft4Validator,
@@ -235,18 +234,6 @@ def missing_date_fromisoformat(test):
             subject="uniqueItems",
             description='{"a": true} and {"a": 1} are unique',
         )(test)
-        or skip(
-            message=bug(743),
-            subject="float-overflow",
-        )(test)
-        or skip(
-            message=bug(743),
-            subject="multipleOf",
-            description=(
-                "always invalid, but naive implementations "
-                "may raise an overflow error"
-            ),
-        )(test)
     ),
 )
 
@@ -255,7 +242,6 @@ def missing_date_fromisoformat(test):
     DRAFT6.tests(),
     DRAFT6.format_tests(),
     DRAFT6.optional_tests_of(name="bignum"),
-    DRAFT6.optional_tests_of(name="float-overflow"),
     DRAFT6.optional_tests_of(name="non-bmp-regex"),
     Validator=Draft6Validator,
     format_checker=draft6_format_checker,
@@ -348,18 +334,6 @@ def missing_date_fromisoformat(test):
             subject="const",
             case_description='const with {"a": true} does not match {"a": 1}',
         )(test)
-        or skip(
-            message=bug(743),
-            subject="float-overflow",
-        )(test)
-        or skip(
-            message=bug(743),
-            subject="multipleOf",
-            description=(
-                "always invalid, but naive implementations "
-                "may raise an overflow error"
-            ),
-        )(test)
     ),
 )
 
@@ -368,7 +342,6 @@ def missing_date_fromisoformat(test):
     DRAFT7.tests(),
     DRAFT7.format_tests(),
     DRAFT7.optional_tests_of(name="bignum"),
-    DRAFT7.optional_tests_of(name="float-overflow"),
     DRAFT7.optional_tests_of(name="content"),
     DRAFT7.optional_tests_of(name="non-bmp-regex"),
     Validator=Draft7Validator,
@@ -484,18 +457,6 @@ def missing_date_fromisoformat(test):
             subject="const",
             case_description='const with {"a": true} does not match {"a": 1}',
         )(test)
-        or skip(
-            message=bug(743),
-            subject="float-overflow",
-        )(test)
-        or skip(
-            message=bug(743),
-            subject="multipleOf",
-            description=(
-                "always invalid, but naive implementations "
-                "may raise an overflow error"
-            ),
-        )(test)
     ),
 )