ganache-core merged my PR, so I changed some comments to clarify that ganache-core v2.2.1 and below will return the non-standard '0x0'

app/scripts/controllers/transactions/tx-gas-utils.js

@@ -63,14 +63,15 @@ class TxGasUtil {
     const hasRecipient = Boolean(recipient)
 
     if (hasRecipient) {
-      let code = await this.query.getCode(recipient)
+      const code = await this.query.getCode(recipient)
 
       // If there's data in the params, but there's no code, it's not a valid contract
-      // For no code, Infura will return '0x', and Ganache will return '0x0'
+      // For no code, Infura will return '0x', and ganache-core v2.2.1 will return '0x0'
       if (txParams.data && (!code || code === '0x' || code === '0x0')) {
-        throw {errorKey: TRANSACTION_NO_CONTRACT_ERROR_KEY}
+        const err = new Error()
-      }
+        err.errorKey = TRANSACTION_NO_CONTRACT_ERROR_KEY
-      else if (!code) {
+        throw err
+      } else if (!code) {
         txParams.gas = SIMPLE_GAS_COST // For a standard ETH send, gas is 21k max
         txMeta.simpleSend = true // Prevents buffer addition
         return SIMPLE_GAS_COST

old-ui/app/components/pending-tx.js

@@ -489,7 +489,7 @@ PendingTx.prototype.verifyGasParams = function () {
 }
 
 PendingTx.prototype._notZeroOrEmptyString = function (obj) {
-  return obj !== '' && obj !== '0x0' && obj !== '0x' // The '0x' case might not ever happen, but it seems safest to protect against it
+  return obj !== '' && obj !== '0x0' && obj !== '0x' // '0x' means null
 }
 
 PendingTx.prototype.bnMultiplyByFraction = function (targetBN, numerator, denominator) {

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' || code === '0x0') { // Infura will return '0x', and Ganache will return '0x0'
+    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) {

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' && code !== '0x0'; // Infura will return '0x', and Ganache will return '0x0'
+  return code && code !== '0x' && code !== '0x0' // Infura will return '0x', and ganache-core v2.2.1 will return '0x0'
 }
 
 export function sumHexes (...args) {