fix #643: child process doesn't exit

CHANGELOG.md

@@ -12,6 +12,10 @@
 
     In addition to being a useful feature, this change also simplifies esbuild's internals. Previously esbuild had to maintain separate child processes if the current working directory was changed in between build API calls. Now esbuild will always reuse the same child process across all build API calls. The `stop()` call on the `startService()` API is also now a no-op (it doesn't do anything anymore) and the `startService()` API may be removed in future releases.
 
+* Fix stray `esbuild` process after `node` exits ([#643](https://github.com/evanw/esbuild/issues/643))
+
+    I discovered that using esbuild's JavaScript incremental build API could result in the child `esbuild` process not exiting when the parent `node` process exits. This was due to a reference counting issue. The bug has been fixed so this shouldn't happen anymore.
+
 ## 0.8.38
 
 * Implement a simple cross-platform watch mode ([#21](https://github.com/evanw/esbuild/issues/21))

cmd/esbuild/service.go

@@ -207,7 +207,7 @@ func (service *serviceType) handleIncomingPacket(bytes []byte) (result outgoingP
 				defer service.mutex.Unlock()
 				if watchStop, ok := service.watchStops[watchID]; ok {
 					// This watch is now considered finished. This matches the +1 reference
-					// count at the return of the serve call.
+					// count at the return of the build call.
 					refCount = -1
 					return watchStop
 				}
@@ -257,7 +257,7 @@ func (service *serviceType) handleIncomingPacket(bytes []byte) (result outgoingP
 				// Only mutate the map while inside a mutex
 				service.mutex.Lock()
 				defer service.mutex.Unlock()
-				if _, ok := service.rebuilds[rebuildID]; !ok {
+				if _, ok := service.rebuilds[rebuildID]; ok {
 					// This build is now considered finished. This matches the +1 reference
 					// count at the return of the first build call for this rebuild chain.
 					refCount = -1

scripts/node-unref-tests.js

@@ -32,6 +32,7 @@ async function tests() {
     })
     assert.deepStrictEqual(result.outputFiles.length, 1);
     assert.deepStrictEqual(result.outputFiles[0].text, '1 + 2;\n');
+    assert.deepStrictEqual(result.stop, void 0);
 
     const result2 = await result.rebuild()
     assert.deepStrictEqual(result2.outputFiles.length, 1);
@@ -44,11 +45,41 @@ async function tests() {
     result2.rebuild.dispose()
   }
 
+  async function testWatch() {
+    const result = await esbuild.build({
+      stdin: { contents: '1+2' },
+      write: false,
+      watch: true,
+    })
+
+    assert.deepStrictEqual(result.rebuild, void 0);
+    assert.deepStrictEqual(result.outputFiles.length, 1);
+    assert.deepStrictEqual(result.outputFiles[0].text, '1 + 2;\n');
+
+    result.stop()
+  }
+
+  async function testWatchAndIncremental() {
+    const result = await esbuild.build({
+      stdin: { contents: '1+2' },
+      write: false,
+      incremental: true,
+      watch: true,
+    })
+
+    assert.deepStrictEqual(result.outputFiles.length, 1);
+    assert.deepStrictEqual(result.outputFiles[0].text, '1 + 2;\n');
+
+    result.stop()
+    result.rebuild.dispose()
+  }
+
   const service = await esbuild.startService();
   try {
     await testTransform()
     await testServe()
     await testBuild()
+    await testWatch()
   } catch (error) {
     service.stop();
     throw error;