fix(child-process-utils): correct handling of iteration interruption

Author: dangreen

packages/child-process-utils/src/index.spec.ts

@@ -79,6 +79,32 @@ describe('child-process-utils', () => {
         }
       }).rejects.toThrow('Process exited with non-zero code')
     })
+
+    it('should kill process on loop break', async () => {
+      const childProcess = child(`
+        (async () => {
+          for (let i = 3; i > 0; i--) {
+            console.log('log' + i)
+            await new Promise((resolve) => setTimeout(resolve, 1000))
+          }
+        })()
+      `)
+      const output = outputStream(childProcess)
+      const start = Date.now()
+      let result = ''
+
+      for await (const line of output) {
+        result = line.toString()
+        break
+      }
+
+      await exitCode(childProcess)
+
+      const end = Date.now()
+
+      expect(result).toBe('log3\n')
+      expect(end - start).toBeLessThan(100)
+    })
   })
 
   describe('output', () => {

packages/child-process-utils/src/index.ts

@@ -64,13 +64,27 @@ export async function throwProcessError(process: ChildProcess) {
  * @yields The stdout of the process.
  */
 export async function* outputStream(process: ChildProcess) {
-  const error = throwProcessError(process)
+  const { stdout } = process
+  const errorPromise = catchProcessError(process)
 
-  if (process.stdout) {
-    yield* process.stdout as AsyncIterable<Buffer>
+  if (stdout) {
+    stdout.on('error', (err) => {
+      // Iteration was interrupted, e.g. by `break` or `return` in a for-await loop.
+      if (err.name === 'AbortError' && process.exitCode === null) {
+        process.kill('SIGKILL')
+      }
+    })
+
+    yield* stdout as AsyncIterable<Buffer>
   }
 
-  await error
+  // Handle error only if iteration was not interrupted.
+
+  const error = await errorPromise
+
+  if (error) {
+    throw error
+  }
 }
 
 /**