feat: coverage without emit

For solc version below 0.4.21

fixes #1230

src/lib/modules/coverage/contractEnhanced.ts

@@ -30,7 +30,7 @@ export class ContractEnhanced {
   private coverageFilepath: string;
   private functionsBodyLocation: {[id: number]: Location} = {};
 
-  constructor(public filepath: string) {
+  constructor(public filepath: string, public solcVersion: string) {
     this.id = nextId();
     this.source = fs.readFileSync(filepath, "utf-8");
     this.originalSource = this.source;

src/lib/modules/coverage/index.ts

@@ -18,7 +18,6 @@ export default class Coverage {
 
   constructor(private embark: Embark, options: any) {
     fs.ensureDirSync(coverageContractsPath());
-
     const contractsDirConfig = this.embark.config.embarkConfig.contracts;
     this.contractsDir = Array.isArray(contractsDirConfig) ? contractsDirConfig : [contractsDirConfig];
 
@@ -33,12 +32,13 @@ export default class Coverage {
   }
 
   private getContracts() {
+    const solcVersion = this.embark.config.embarkConfig.versions.solc;
     const filepaths = this.contractsDir.reduce((acc: string[], pattern: string) => (
       acc.concat(globule.find(pattern, { prefixBase: false, srcBase: fs.dappPath() }))
     ), []);
 
     return filepaths.filter((filepath) => fs.statSync(filepath).isFile())
-                    .map((filepath) => new ContractEnhanced(filepath));
+                    .map((filepath) => new ContractEnhanced(filepath, solcVersion));
   }
 
   private instrumentContracts() {

src/lib/modules/coverage/injector.ts

@@ -1,10 +1,15 @@
+import * as semver from "semver";
 import { ContractEnhanced } from "./contractEnhanced";
 import { encrypt } from "./eventId";
 import { InjectionPoint } from "./types";
 
+const EMIT_VERSION =  "0.4.21";
+
 export class Injector {
+  private isEmitSupported: boolean;
 
   constructor(private contract: ContractEnhanced) {
+    this.isEmitSupported = semver.gte(this.contract.solcVersion, EMIT_VERSION);
   }
 
   public process(injectionPoint: InjectionPoint) {
@@ -17,7 +22,7 @@ export class Injector {
   }
 
   private statement(injectionPoint: InjectionPoint) {
-    const data = `emit __StatementCoverage(${encrypt(this.contract.id, injectionPoint.id)});`;
+    const data = `${this.isEmitSupported ? "emit" : ""} __StatementCoverage(${encrypt(this.contract.id, injectionPoint.id)});`;
     this.insertAt(injectionPoint.location.start.line - 1, data);
   }
 

src/typings/embark.d.ts

@@ -20,6 +20,9 @@ export interface Embark {
       config: {
         contracts: string;
       };
+      versions: {
+        solc: string;
+      }
     };
     reloadConfig(): void;
   };