From d03f13a72929d680ea3ec3123edb9795ccf14049 Mon Sep 17 00:00:00 2001
From: Lawrence Forman <lawrence@0xproject.com>
Date: Thu, 1 Aug 2019 13:10:48 -0400
Subject: [PATCH] `@0x/contracts-utils`: `LibMath._safeDiv()` now throws a rich
 revert when dividing by zero.

---
 .../contracts/src/LibSafeMathRichErrors.sol      |  3 ++-
 contracts/utils/contracts/src/SafeMath.sol       |  7 +++++++
 contracts/utils/src/reference_functions.ts       | 16 +++++++++++-----
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/contracts/utils/contracts/src/LibSafeMathRichErrors.sol b/contracts/utils/contracts/src/LibSafeMathRichErrors.sol
index a1f39cc41d..0b13af3706 100644
--- a/contracts/utils/contracts/src/LibSafeMathRichErrors.sol
+++ b/contracts/utils/contracts/src/LibSafeMathRichErrors.sol
@@ -10,7 +10,8 @@ library LibSafeMathRichErrors {
     enum SafeMathErrorCodes {
         UINT256_ADDITION_OVERFLOW,
         UINT256_MULTIPLICATION_OVERFLOW,
-        UINT256_SUBTRACTION_UNDERFLOW
+        UINT256_SUBTRACTION_UNDERFLOW,
+        UINT256_DIVISION_BY_ZERO
     }
 
     // solhint-disable func-name-mixedcase
diff --git a/contracts/utils/contracts/src/SafeMath.sol b/contracts/utils/contracts/src/SafeMath.sol
index ed22105a9a..1edc1bac93 100644
--- a/contracts/utils/contracts/src/SafeMath.sol
+++ b/contracts/utils/contracts/src/SafeMath.sol
@@ -30,6 +30,13 @@ contract SafeMath {
         pure
         returns (uint256)
     {
+        if (b == 0) {
+            LibRichErrors._rrevert(LibSafeMathRichErrors.SafeMathError(
+                LibSafeMathRichErrors.SafeMathErrorCodes.UINT256_DIVISION_BY_ZERO,
+                a,
+                b
+            ));
+        }
         uint256 c = a / b;
         return c;
     }
diff --git a/contracts/utils/src/reference_functions.ts b/contracts/utils/src/reference_functions.ts
index 717baafc09..e623ef639f 100644
--- a/contracts/utils/src/reference_functions.ts
+++ b/contracts/utils/src/reference_functions.ts
@@ -1,4 +1,4 @@
-import { AnyRevertError, BigNumber, SafeMathRevertErrors } from '@0x/utils';
+import { BigNumber, SafeMathRevertErrors } from '@0x/utils';
 
 const MAX_UINT256 = new BigNumber(2).pow(256).minus(1);
 
@@ -29,16 +29,22 @@ export function safeSub(a: BigNumber, b: BigNumber): BigNumber {
 export function safeMul(a: BigNumber, b: BigNumber): BigNumber {
     const r = a.times(b);
     if (r.isGreaterThan(MAX_UINT256)) {
-        // Solidity implementation does not throw a reason.
-        throw new AnyRevertError();
+        throw new SafeMathRevertErrors.SafeMathError(
+            SafeMathRevertErrors.SafeMathErrorCodes.Uint256MultiplicationOverflow,
+            a,
+            b,
+        );
     }
     return r;
 }
 
 export function safeDiv(a: BigNumber, b: BigNumber): BigNumber {
     if (b.isEqualTo(0)) {
-        // Solidity implementation does not throw a reason.
-        throw new AnyRevertError();
+        throw new SafeMathRevertErrors.SafeMathError(
+            SafeMathRevertErrors.SafeMathErrorCodes.Uint256DivisionByZero,
+            a,
+            b,
+        );
     }
     return a.dividedToIntegerBy(b);
 }