Use Workers for earlier compilers

packages/lib-sourcify/src/lib/compilerWorker.ts

@@ -0,0 +1,13 @@
+import { workerData, parentPort } from 'worker_threads';
+import { getSolcJs } from './solidityCompiler';
+
+async function runUseCompiler(version: string, inputStringified: string) {
+  const solJson = await getSolcJs(version);
+  const result = solJson.compile(inputStringified);
+  if (parentPort === null) {
+    throw new Error('Parent port is null; cannot send compilation result');
+  }
+  parentPort.postMessage(result);
+}
+
+runUseCompiler(workerData.version, workerData.inputStringified);

packages/lib-sourcify/src/lib/solidityCompiler.ts

@@ -6,6 +6,8 @@ import { fetchWithTimeout } from './utils';
 import { StatusCodes } from 'http-status-codes';
 import { JsonInput, PathBuffer } from './types';
 import { logDebug, logError, logInfo, logWarn } from './logger';
+import semver from 'semver';
+import { Worker, WorkerOptions } from 'worker_threads';
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 const solc = require('solc');
 
@@ -76,11 +78,31 @@ export async function useCompiler(version: string, solcJsonInput: JsonInput) {
     }
     compiled = shellOutputBuffer.stdout.toString();
   } else {
-    const soljson = await getSolcJs(version);
+    const solJson = await getSolcJs(version);
     startCompilation = Date.now();
     logDebug(`Compiling with solc-js ${version}`);
-    if (soljson) {
-      compiled = soljson.compile(inputStringified);
+    if (solJson) {
+      const coercedVersion =
+        semver.coerce(new semver.SemVer(version))?.version ?? '';
+      // Run Worker for solc versions < 0.4.0 for clean compiler context. See https://github.com/ethereum/sourcify/issues/1099
+      if (semver.lt(coercedVersion, '0.4.0')) {
+        compiled = await new Promise((resolve, reject) => {
+          let worker = importWorker(
+            path.resolve(__dirname, './compilerWorker.ts'),
+            {
+              workerData: { version, inputStringified },
+            }
+          );
+          worker.once('message', (result) => {
+            resolve(result);
+          });
+          worker.once('error', (error) => {
+            reject(error);
+          });
+        });
+      } else {
+        compiled = solJson.compile(inputStringified);
+      }
     }
   }
 
@@ -112,6 +134,7 @@ export async function getAllMetadataAndSourcesFromSolcJson(
     throw new Error(
       'Only Solidity is supported, the json has language: ' + solcJson.language
     );
+
   const outputSelection = {
     '*': {
       '*': ['metadata'],
@@ -278,3 +301,14 @@ export async function getSolcJs(version = 'latest'): Promise<any> {
   const solcjsImports = await import(soljsonPath);
   return solc.setupMethods(solcjsImports);
 }
+
+// https://stackoverflow.com/questions/71795469/ts-node-using-worker-thread-cause-cannot-use-import-statement-outside-a-module
+function importWorker(path: string, options: WorkerOptions) {
+  const resolvedPath = require.resolve(path);
+  return new Worker(resolvedPath, {
+    ...options,
+    execArgv: /\.ts$/.test(resolvedPath)
+      ? ['--require', 'ts-node/register']
+      : undefined,
+  });
+}

packages/lib-sourcify/test/functions.spec.ts

@@ -16,7 +16,8 @@ import storageMetadata from './sources/Storage/metadata.json';
 import { Metadata, MissingSources } from '../src/lib/types';
 import WrongMetadata from './sources/WrongMetadata/metadata.json';
 import SimplyLog from './sources/WrongMetadata/SimplyLog.json';
-
+import earlyCompilerInput from './sources/json-input/pre-v0.4.0/input.json';
+import { keccak256 } from 'ethers';
 describe('Verify Solidity Compiler', () => {
   it('Should fetch latest SolcJS compiler', async () => {
     expect(await getSolcJs()).not.equals(null);
@@ -111,6 +112,24 @@ describe('Verify Solidity Compiler', () => {
       });
     }
   });
+
+  // See https://github.com/ethereum/sourcify/issues/1099
+  it(`Should should use a clean compiler context with pre 0.4.0 versions`, async () => {
+    // Run compiler once to change compiler "context"
+    await useCompiler('0.1.5+commit.23865e3', earlyCompilerInput);
+
+    // A second run needs to produce the same result
+    const compilerResult = await useCompiler(
+      '0.1.5+commit.23865e3',
+      earlyCompilerInput
+    );
+    const compiledBytecode = compilerResult.contracts[''].GroveLib.evm
+      .deployedBytecode.object as string;
+    const compiledHash = keccak256('0x' + compiledBytecode);
+    expect(compiledHash).equals(
+      '0xc778f3d42ce4a7ee21a2e93d45265cf771e5970e0e36f882310f4491d0ca889d'
+    );
+  });
 });
 
 describe('Checked contract', () => {