onFinish callback never fires when stream is aborted - partial AI messages lost on client disconnect

[ldriss]

When a user aborts a streaming AI response (client disconnect, page refresh, or manual stop), the onFinish callback never executes, causing partial AI messages to be lost forever. This breaks conversation history and
creates a poor UX.

🔄 Current Behavior

// User message - saved immediately ✅
await saveMessages([userMessage]);

const result = streamText({
  model,
  messages,
  onFinish: async ({ response }) => {
    // This NEVER executes when stream is aborted ❌
    await saveMessages([aiMessage]); 
  }
});

result.consumeStream(); // Doesn't help - still gets killed

Result: User refreshes page → only user message visible, AI response gone.

✅ Expected Behavior
Partial AI responses should be persisted even when streams are interrupted, maintaining conversation continuity.

Thanks