fix(teeny-request): destroy response stream if request stream is destroyed early

[westarle]

If the consumer destroys the returned stream before piping starts, teeny-request should skip pipeline construction and destroy the unused response body. This prevents unhandled rejections (e.g. ERR_STREAM_UNABLE_TO_PIPE) when trying to pipe to a closed/destroyed stream.

Fixes: 8670

[gemini-code-assist]

Code Review

This pull request prevents piping streams if the request stream is destroyed early, and ensures the response stream is properly destroyed instead. It also adds a test case to verify this behavior. The review feedback suggests simplifying a redundant null-check on responseStream and refactoring the test to avoid using setTimeout, which can cause flakiness in CI/CD environments.

[gemini-code-assist]

The check responseStream && is redundant here because this block is already nested inside if (responseStream) on line 280. We can safely simplify this condition.

        if (!requestStream.destroyed) {
          pipeline(responseStream, requestStream, () => {});
        } else if (typeof responseStream.destroy === 'function') {
          responseStream.destroy();
        }

[gemini-code-assist]

Using an arbitrary setTimeout in asynchronous tests can lead to flakiness in slower CI/CD environments. Since we expect the stream to be destroyed, we can listen directly to the close event of the response body to resolve the test, which is more robust and faster.

  it('should not pipe if request stream is destroyed early', done => {
    const scope = mockJson();

    const stream = teenyRequest({uri});
    stream.on('error', done);

    stream.once('response', response => {
      response.body.once('close', () => {
        scope.done();
        done();
      });

      // Destroy the stream before piping can be fully set up
      stream.destroy();
    });

    stream.resume();
  });