Fix #1657: bug where node flags were not correctly preserved in execArgv

src/bin.ts

@@ -376,7 +376,7 @@ Options:
   }
 
   // Prepend `ts-node` arguments to CLI for child processes.
-  process.execArgv.unshift(
+  process.execArgv.push(
     __filename,
     ...process.argv.slice(2, process.argv.length - args._.length)
   );

src/test/helpers.ts

@@ -29,6 +29,7 @@ export const DIST_DIR = resolve(__dirname, '..');
 export const TEST_DIR = join(__dirname, '../../tests');
 export const PROJECT = join(TEST_DIR, 'tsconfig.json');
 export const BIN_PATH = join(TEST_DIR, 'node_modules/.bin/ts-node');
+export const BIN_PATH_JS = join(TEST_DIR, 'node_modules/ts-node/dist/bin.js');
 export const BIN_SCRIPT_PATH = join(
   TEST_DIR,
   'node_modules/.bin/ts-node-script'

src/test/index.spec.ts

@@ -3,7 +3,7 @@ import * as expect from 'expect';
 import { join, resolve, sep as pathSep } from 'path';
 import { tmpdir } from 'os';
 import semver = require('semver');
-import { nodeSupportsEsmHooks, ts } from './helpers';
+import { BIN_PATH_JS, nodeSupportsEsmHooks, ts } from './helpers';
 import { lstatSync, mkdtempSync } from 'fs';
 import { npath } from '@yarnpkg/fslib';
 import type _createRequire from 'create-require';
@@ -1071,6 +1071,44 @@ test('Falls back to transpileOnly when ts compiler returns emitSkipped', async (
   expect(stdout).toBe('foo\n');
 });
 
+test.suite('node environment', (test) => {
+  test.suite('Sets argv and execArgv correctly in forked processes', (test) => {
+    forkTest(`node --no-warnings ${BIN_PATH_JS}`, BIN_PATH_JS, '--no-warnings');
+    forkTest(
+      `${BIN_PATH}`,
+      process.platform === 'win32' ? BIN_PATH_JS : BIN_PATH
+    );
+
+    function forkTest(
+      command: string,
+      expectParentArgv0: string,
+      nodeFlag?: string
+    ) {
+      test(command, async (t) => {
+        const { err, stderr, stdout } = await exec(
+          `${command} --skipIgnore ./recursive-fork/index.ts argv2`
+        );
+        expect(err).toBeNull();
+        expect(stderr).toBe('');
+        const generations = stdout.split('\n');
+        const expectation = {
+          execArgv: [nodeFlag, BIN_PATH_JS, '--skipIgnore'].filter((v) => v),
+          argv: [
+            // Note: argv[0] is *always* BIN_PATH_JS in child & grandchild
+            expectParentArgv0,
+            resolve(TEST_DIR, 'recursive-fork/index.ts'),
+            'argv2',
+          ],
+        };
+        expect(JSON.parse(generations[0])).toMatchObject(expectation);
+        expectation.argv[0] = BIN_PATH_JS;
+        expect(JSON.parse(generations[1])).toMatchObject(expectation);
+        expect(JSON.parse(generations[2])).toMatchObject(expectation);
+      });
+    }
+  });
+});
+
 test('Detect when typescript adds new ModuleKind values; flag as a failure so we can update our code flagged [MUST_UPDATE_FOR_NEW_MODULEKIND]', async () => {
   // We have marked a few places in our code with MUST_UPDATE_FOR_NEW_MODULEKIND to make it easier to update them when TS adds new ModuleKinds
   const foundKeys: string[] = [];

tests/recursive-fork/index.ts

@@ -0,0 +1,11 @@
+import { fork } from 'child_process';
+
+console.log(JSON.stringify({ execArgv: process.execArgv, argv: process.argv }));
+if (process.env.generation !== 'grandchild') {
+  const nextGeneration =
+    process.env.generation === 'child' ? 'grandchild' : 'child';
+  fork(__filename, process.argv.slice(2), {
+    env: { ...process.env, generation: nextGeneration },
+    stdio: 'inherit',
+  });
+}

tests/recursive-fork/package.json

@@ -0,0 +1 @@
+{}

tests/recursive-fork/tsconfig.json

@@ -0,0 +1,5 @@
+{
+  "compilerOptions": {
+    "moduleResolution": "node"
+  }
+}