From 0ef36c9949f4695d2ba1eda8b5d6e9119c1bceaa Mon Sep 17 00:00:00 2001
From: cgewecke <christophergewecke@gmail.com>
Date: Mon, 9 Sep 2019 23:35:29 -0700
Subject: [PATCH] Attach to non-fork ganache vm (#391)

---
 dist/truffle.plugin.js |  5 +--
 lib/app.js             | 69 +++++++++++++++++++++++++++++++++++++++---
 lib/ui.js              |  3 ++
 test/units/app.js      |  4 ++-
 4 files changed, 74 insertions(+), 7 deletions(-)

diff --git a/dist/truffle.plugin.js b/dist/truffle.plugin.js
index d7b762b..85d8bb0 100644
--- a/dist/truffle.plugin.js
+++ b/dist/truffle.plugin.js
@@ -32,7 +32,6 @@ const path = require('path');
 const dir = require('node-dir');
 const Web3 = require('web3');
 const util = require('util');
-const ganache = require('ganache-core-sc');
 const globby = require('globby');
 
 async function plugin(truffleConfig){
@@ -70,7 +69,7 @@ async function plugin(truffleConfig){
     death(app.cleanUp);
 
     // Launch in-process provider
-    const provider = await app.provider(ganache);
+    const provider = await app.provider(truffle.ganache);
     const web3 = new Web3(provider);
     const accounts = await web3.eth.getAccounts();
     const nodeInfo = await web3.eth.getNodeInfo();
@@ -153,6 +152,8 @@ function loadTruffleLibrary(){
   try { return require("./truffle.library")} catch(err) {};
 
   // TO DO: throw error? This point should never be reached.
+  // Validate that truffle.ganache exists? Have checked that
+  // a non-existent prop defaults to the ganache-core-sc fallback FWIW.
 }
 
 /**
diff --git a/lib/app.js b/lib/app.js
index 986282d..57dff5d 100644
--- a/lib/app.js
+++ b/lib/app.js
@@ -3,6 +3,7 @@ const fs = require('fs');
 const path = require('path');
 const istanbul = require('istanbul');
 const util = require('util');
+const assert = require('assert');
 
 const Instrumenter = require('./instrumenter');
 const Coverage = require('./coverage');
@@ -113,15 +114,31 @@ class App {
    *
    * TODO: generalize provider options setting for non-ganache clients..
    */
-  provider(client){
-    if(!this.client) this.client = client;
+  async provider(client){
+    let retry = false;
+
+    if(!this.client) this.client = client; // Prefer client from options
+
     this.collector = new DataCollector(this.instrumenter.instrumentationData);
 
     this.providerOptions.gasLimit = this.gasLimitString;
     this.providerOptions.allowUnlimitedContractSize = true;
-    this.providerOptions.logger = { log: this.collector.step.bind(this.collector) };
 
-    this.provider = this.client.provider(this.providerOptions);
+    // Try to launch provider and attach to vm step of
+    // either plugin's ganache or a provider passed via options
+    try {
+      this.provider = await this.attachToVM();
+    } catch(err){
+      retry = true;
+      this.ui.report('vm-fail', [])
+    }
+
+    // Fallback to ganache-core-sc (eq: ganache-core 2.7.0)
+    if (retry){
+      this.providerOptions.logger = { log: this.collector.step.bind(this.collector) };
+      this.client = require('ganache-core-sc');
+      this.provider = this.client.provider(this.providerOptions);
+    }
 
     return this.provider;
   }
@@ -176,6 +193,50 @@ class App {
   }
   // ------------------------------------------ Utils ----------------------------------------------
 
+  // ========
+  // Provider
+  // ========
+  async attachToVM(){
+    const self = this;
+    const provider = this.client.provider(this.providerOptions);
+
+    this.assertHasBlockchain(provider);
+
+    await this.vmIsResolved(provider);
+
+    const blockchain = provider.engine.manager.state.blockchain;
+    const createVM = blockchain.createVMFromStateTrie;
+
+    // Attach to VM which ganache has already instantiated
+    // and which it uses to execute eth_send
+    blockchain.vm.on('step', self.collector.step.bind(self.collector));
+
+    // Attach/hijack createVM method which ganache uses to run eth_calls
+    blockchain.createVMFromStateTrie = function(state, activatePrecompiles) {
+      const vm = createVM.apply(blockchain, arguments);
+      vm.on('step', self.collector.step.bind(self.collector));
+      return vm;
+    }
+
+    return provider;
+  }
+
+  assertHasBlockchain(provider){
+    assert(provider.engine.manager.state.blockchain !== undefined);
+    assert(provider.engine.manager.state.blockchain.createVMFromStateTrie !== undefined);
+  }
+
+  async vmIsResolved(provider){
+    return new Promise(resolve => {
+      const interval = setInterval(() => {
+        if (provider.engine.manager.state.blockchain.vm !== undefined){
+          clearInterval(interval);
+          resolve();
+        }
+      });
+    })
+  }
+
   // ========
   // File I/O
   // ========
diff --git a/lib/ui.js b/lib/ui.js
index c396808..4ec4142 100644
--- a/lib/ui.js
+++ b/lib/ui.js
@@ -22,6 +22,9 @@ class UI {
     const ds = c.bold.yellow('>');
 
     const kinds = {
+      'vm-fail': `:warning:  ${c.red('There was a problem attaching to the ganache-core VM.')} `+
+                            `${c.red('Check the provider option syntax in solidity-coverage docs.')}\n`+
+                 `:warning:  ${c.red('Using ganache-core-sc (eq. core v2.7.0) instead.')}\n`,
 
       'truffle-help': `Usage: truffle run coverage [options]\n\n` +
                       `Options:\n` +
diff --git a/test/units/app.js b/test/units/app.js
index 3ebaaa3..1323806 100644
--- a/test/units/app.js
+++ b/test/units/app.js
@@ -100,7 +100,9 @@ describe('app', function() {
     await plugin(truffleConfig);
   });
 
-  it('project uses multiple migrations', async function() {
+  // This project has three contract suites and uses .deployed() instances which
+  // depend on truffle's migratons and the inter-test evm_revert / evm_snapshot mechanism.
+  it('project evm_reverts repeatedly', async function() {
     assertCleanInitialState();
     mock.installFullProject('multiple-migrations');
     await plugin(truffleConfig);