8 files changed, 35 insertions, 13 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5a9d7703c..e09cd47dd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Current Develop Branch
 
+- [#5283](https://github.com/MetaMask/metamask-extension/pull/5283): Fix bug when eth.getCode() called with no contract
+
 ## 4.16.0 Wednesday October 17 2018
 
 - Feature: Add toggle for primary currency (eth/fiat)
diff --git a/app/_locales/en/messages.json b/app/_locales/en/messages.json
index bf5854a31..4cdf6b8dc 100644
--- a/app/_locales/en/messages.json
+++ b/app/_locales/en/messages.json
@@ -1175,6 +1175,9 @@
   "transactionError": {
     "message": "Transaction Error. Exception thrown in contract code."
   },
+  "transactionErrorNoContract": {
+    "message": "Trying to call a contract function at an address that is not a contract address."
+  },
   "transactionMemo": {
     "message": "Transaction memo (optional)"
   },
diff --git a/app/scripts/controllers/transactions/tx-gas-utils.js b/app/scripts/controllers/transactions/tx-gas-utils.js
index 3dd45507f..436900715 100644
--- a/app/scripts/controllers/transactions/tx-gas-utils.js
+++ b/app/scripts/controllers/transactions/tx-gas-utils.js
@@ -7,6 +7,8 @@ const {
 const { addHexPrefix } = require('ethereumjs-util')
 const SIMPLE_GAS_COST = '0x5208' // Hex for 21000, cost of a simple send.
 
+import { TRANSACTION_NO_CONTRACT_ERROR_KEY } from '../../../../ui/app/constants/error-keys'
+
 /**
 tx-gas-utils are gas utility methods for Transaction manager
 its passed ethquery
@@ -32,6 +34,7 @@ class TxGasUtil {
     } catch (err) {
       txMeta.simulationFails = {
         reason: err.message,
+        errorKey: err.errorKey,
       }
       return txMeta
     }
@@ -56,24 +59,37 @@ class TxGasUtil {
       return txParams.gas
     }
 
-    // if recipient has no code, gas is 21k max:
     const recipient = txParams.to
     const hasRecipient = Boolean(recipient)
-    let code
-    if (recipient) code = await this.query.getCode(recipient)
 
-    if (hasRecipient && (!code || code === '0x')) {
-      txParams.gas = SIMPLE_GAS_COST
-      txMeta.simpleSend = true // Prevents buffer addition
-      return SIMPLE_GAS_COST
+    // see if we can set the gas based on the recipient 
+    if (hasRecipient) {
+      const code = await this.query.getCode(recipient)
+      // For an address with no code, geth will return '0x', and ganache-core v2.2.1 will return '0x0'
+      const codeIsEmpty = !code || code === '0x' || code === '0x0'
+      
+      if (codeIsEmpty) {
+        // if there's data in the params, but there's no contract code, it's not a valid transaction
+        if (txParams.data) {
+          const err = new Error()
+          err.errorKey = TRANSACTION_NO_CONTRACT_ERROR_KEY
+          throw err
+        }
+        
+        // This is a standard ether simple send, gas requirement is exactly 21k
+        txParams.gas = SIMPLE_GAS_COST
+        // prevents buffer addition
+        txMeta.simpleSend = true
+        return SIMPLE_GAS_COST
+      }
     }
 
-    // if not, fall back to block gasLimit
+    // fallback to block gasLimit
     const blockGasLimitBN = hexToBn(blockGasLimitHex)
     const saferGasLimitBN = BnMultiplyByFraction(blockGasLimitBN, 19, 20)
     txParams.gas = bnToHex(saferGasLimitBN)
 
-    // run tx
+    // estimate tx gas requirements
     return await this.query.estimateGas(txParams)
   }
 
diff --git a/old-ui/app/components/pending-tx.js b/old-ui/app/components/pending-tx.js
index c8132539c..d8d2334a4 100644
--- a/old-ui/app/components/pending-tx.js
+++ b/old-ui/app/components/pending-tx.js
@@ -489,7 +489,7 @@ PendingTx.prototype.verifyGasParams = function () {
 }
 
 PendingTx.prototype._notZeroOrEmptyString = function (obj) {
-  return obj !== '' && obj !== '0x0'
+  return obj !== '' && obj !== '0x0' && obj !== '0x' // '0x' means null
 }
 
 PendingTx.prototype.bnMultiplyByFraction = function (targetBN, numerator, denominator) {
diff --git a/ui/app/components/pages/confirm-transaction-base/confirm-transaction-base.component.js b/ui/app/components/pages/confirm-transaction-base/confirm-transaction-base.component.js
index c92867afe..7d01aaffb 100644
--- a/ui/app/components/pages/confirm-transaction-base/confirm-transaction-base.component.js
+++ b/ui/app/components/pages/confirm-transaction-base/confirm-transaction-base.component.js
@@ -136,7 +136,7 @@ export default class ConfirmTransactionBase extends Component {
     if (simulationFails) {
       return {
         valid: true,
-        errorKey: TRANSACTION_ERROR_KEY,
+        errorKey: simulationFails.errorKey ? simulationFails.errorKey : TRANSACTION_ERROR_KEY,
       }
     }
 
diff --git a/ui/app/components/send/send.utils.js b/ui/app/components/send/send.utils.js
index a18a9e4b3..af7b3823f 100644
--- a/ui/app/components/send/send.utils.js
+++ b/ui/app/components/send/send.utils.js
@@ -215,7 +215,7 @@ async function estimateGas ({
   // if recipient has no code, gas is 21k max:
   if (!selectedToken && !data) {
     const code = Boolean(to) && await global.eth.getCode(to)
-    if (!code || code === '0x') {
+    if (!code || code === '0x' || code === '0x0') { // Infura will return '0x', and ganache-core v2.2.1 will return '0x0'
       return SIMPLE_GAS_COST
     }
   } else if (selectedToken && !to) {
diff --git a/ui/app/constants/error-keys.js b/ui/app/constants/error-keys.js
index f70ed3b19..704064c96 100644
--- a/ui/app/constants/error-keys.js
+++ b/ui/app/constants/error-keys.js
@@ -1,3 +1,4 @@
 export const INSUFFICIENT_FUNDS_ERROR_KEY = 'insufficientFunds'
 export const GAS_LIMIT_TOO_LOW_ERROR_KEY = 'gasLimitTooLow'
 export const TRANSACTION_ERROR_KEY = 'transactionError'
+export const TRANSACTION_NO_CONTRACT_ERROR_KEY = 'transactionErrorNoContract'
diff --git a/ui/app/helpers/transactions.util.js b/ui/app/helpers/transactions.util.js
index e50196196..9be77e14f 100644
--- a/ui/app/helpers/transactions.util.js
+++ b/ui/app/helpers/transactions.util.js
@@ -114,7 +114,7 @@ export function getLatestSubmittedTxWithNonce (transactions = [], nonce = '0x0')
 
 export async function isSmartContractAddress (address) {
   const code = await global.eth.getCode(address)
-  return code && code !== '0x'
+  return code && code !== '0x' && code !== '0x0' // Infura will return '0x', and ganache-core v2.2.1 will return '0x0'
 }
 
 export function sumHexes (...args) {