Return errors when a tx fails in estimation

README.md

@@ -1,5 +1,5 @@
-[![npm](https://img.shields.io/npm/v/ganache-core.svg)]()
-[![npm](https://img.shields.io/npm/dm/ganache-core.svg)]()
+[![npm Version](https://img.shields.io/npm/v/ganache-core.svg)](https://www.npmjs.com/package/ganache-core)
+[![npm Downloads](https://img.shields.io/npm/dm/ganache-core.svg)](https://www.npmjs.com/package/ganache-core)
 [![Build Status](https://travis-ci.org/trufflesuite/ganache-core.svg?branch=master)](https://travis-ci.org/trufflesuite/ganache-core)
 [![Coverage Status](https://coveralls.io/repos/github/trufflesuite/ganache-core/badge.svg?branch=develop)](https://coveralls.io/github/trufflesuite/ganache-core?branch=develop)
 # Ganache Core

lib/blockchain_double.js

@@ -559,7 +559,7 @@ BlockchainDouble.prototype.estimateGas = function(tx, blockNumber, callback) {
       return;
     }
 
-    estimateGas(vm, runArgs, err, callback);
+    estimateGas(vm, runArgs, callback);
   });
 };
 

lib/provider.js

@@ -198,6 +198,9 @@ Provider.prototype.cleanUpErrorObject = function(err, response) {
     errorObject.error.message = err.message;
     errorObject.error.data.stack = err.stack;
     errorObject.error.data.name = err.name;
+    if ("code" in err) {
+      errorObject.error.code = err.code;
+    }
   } else if (!response.error) {
     errorObject.error = {
       message: err.toString()
@@ -242,7 +245,7 @@ Provider.prototype.reportErrorInResponse = function(request, err, response) {
     }
   }
 
-  if (request.method === "eth_call") {
+  if (request.method === "eth_call" || request.method === "eth_estimateGas") {
     if (err instanceof RuntimeError) {
       if (self.options.vmErrorsOnRPCResponse) {
         if (!response.error.data) {

lib/utils/gasEstimation.js

@@ -1,12 +1,18 @@
 const STIPEND = 2300;
-module.exports = (vm, runArgs, err, callback) => {
+module.exports = (vm, runArgs, callback) => {
   const steps = stepTracker();
 
   vm.on("step", steps.collect);
 
   vm.runTx(runArgs, function(vmerr, result) {
     if (vmerr) {
-      return callback(vmerr, err);
+      return callback(vmerr);
+    } else if (result.vm.exception === 0) {
+      const error = result.vm.exceptionError
+        ? new Error(`execution error: ${result.vm.exceptionError.error}`)
+        : new Error("execution error");
+      error.code = -32000;
+      return callback(error);
     } else if (steps.done()) {
       let estimate = result.gasUsed;
       result.gasEstimate = estimate;

package.json

@@ -11,7 +11,7 @@
   },
   "scripts": {
     "_mocha": "mocha --check-leaks --recursive --globals _scratch --opts ./test/.mocharc",
-    "nyc_mocha": "nyc mocha --check-leaks --recursive --globals _scratch --opts ./test/.mocharc",
+    "nyc_mocha": "nyc npm run _mocha",
     "_lint": "eslint --ignore-path .gitignore .",
     "build": "webpack-cli --config ./webpack/node/core.webpack.config.js",
     "build-web": "webpack-cli --config ./webpack/web-experimental/core.webpack.config.js",

test/runTimeErrors.js

@@ -38,6 +38,22 @@ function tests(ganacheProviderOptions) {
         });
     });
 
+    it("Should fail to estimate gas when the transaction is invalid", async() => {
+      const { accounts, instance, send } = context;
+      const txParams = {
+        from: accounts[0],
+        // this errors:
+        to: instance.options.address
+      };
+      const result = await send("eth_estimateGas", txParams);
+      assert.deepStrictEqual(result.response.error.code, -32000, "Gas estimation error code is not as expected");
+      assert.deepStrictEqual(
+        result.response.error.message,
+        "execution error: revert",
+        "Gas estimation error message is not as expected"
+      );
+    });
+
     it("should output the transaction hash even if a (out of gas) runtime error occurred", async function() {
       const { accounts, bytecode, provider, send } = context;