Forward signals correctly (#419)

Author: stelcheck

src/bin.ts

@@ -5,6 +5,7 @@ import { join } from 'path'
 import v8flags = require('v8flags')
 
 const argv = process.argv.slice(2)
+const signals: NodeJS.Signals[] = ['SIGINT', 'SIGTERM', 'SIGWINCH']
 
 v8flags(function (err, v8flags) {
   if (err) {
@@ -53,16 +54,30 @@ v8flags(function (err, v8flags) {
   const proc = spawn(
     process.execPath,
     nodeArgs.concat(join(__dirname, '_bin.js'), scriptArgs),
-    { stdio: 'inherit' }
+    {
+      // We need to run in detached mode so to avoid
+      // automatic propagation of signals to the child process.
+      // This is necessary because by default, keyboard interrupts
+      // are propagated to the process tree, but `kill` is not.
+      //
+      // See: https://nodejs.org/api/child_process.html#child_process_options_detached
+      detached: true,
+      stdio: 'inherit'
+    }
   )
 
-  proc.on('exit', function (code: number, signal: string) {
-    process.on('exit', function () {
-      if (signal) {
-        process.kill(process.pid, signal)
-      } else {
-        process.exit(code)
-      }
-    })
+  // Ignore signals, and instead forward them to the child process.
+  signals.forEach(signal => process.on(signal, () => proc.kill(signal)))
+
+  // On spawned close, exit this process with the same code.
+  proc.on('close', (code: number, signal: string) => {
+    if (signal) {
+      process.kill(process.pid, signal)
+    } else {
+      process.exit(code)
+    }
   })
+
+  // If this process exits, kill the child first.
+  process.on('exit', () => proc.kill())
 })

src/index.spec.ts

@@ -1,5 +1,5 @@
 import { expect } from 'chai'
-import { exec } from 'child_process'
+import { exec, spawn } from 'child_process'
 import { join } from 'path'
 import semver = require('semver')
 import ts = require('typescript')
@@ -20,6 +20,43 @@ describe('ts-node', function () {
   })
 
   describe('cli', function () {
+    this.slow(1000)
+
+    it('should forward signals to the child process', function (done) {
+      this.slow(5000)
+
+      // We use `spawn` instead because apparently TravisCI
+      // does not let subprocesses be killed when ran under `sh`
+      //
+      // See: https://github.com/travis-ci/travis-ci/issues/704#issuecomment-328278149
+      const proc = spawn('node', [
+        EXEC_PATH,
+        '--project',
+        testDir,
+        'tests/signals'
+      ], {
+        shell: '/bin/bash'
+      })
+
+      let stdout = ''
+      proc.stdout.on('data', (data) => stdout += data.toString())
+
+      let stderr = ''
+      proc.stderr.on('data', (data) => stderr += data.toString())
+
+      proc.on('exit', function (code) {
+        expect(stderr).to.equal('')
+        expect(stdout).to.equal('exited fine')
+        expect(code).to.equal(0)
+
+        return done()
+      })
+
+      // Leave enough time for node to fully start
+      // the process, then send a signal
+      setTimeout(() => proc.kill('SIGINT'), 2000)
+    })
+
     it('should execute cli', function (done) {
       exec(`${BIN_EXEC} tests/hello-world`, function (err, stdout) {
         expect(err).to.equal(null)

tests/signals.ts

@@ -0,0 +1,12 @@
+process.on('SIGINT', () => {
+  process.stdout.write('exited')
+  setTimeout(() => {
+    process.stdout.write(' fine')
+
+    // Needed to make sure what we wrote has time
+    // to be written
+    process.nextTick(() => process.exit())
+  }, 500)
+})
+
+setInterval(() => console.log('should not be reached'), 3000)