RFR: 8208693: HttpClient: Extend the request timeout's scope to cover the response body [v3]

[Volkan Yazici]

On Wed, 22 Oct 2025 12:20:41 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

> Could we remove the `preTerminationCallback` parameter, and instead have the various subclass of `HttpBodySubscriberWrapper` supply `this.multi::cancelTimer()` to their super class?
> 
> If I'm not mistaken all concrete subclasses of `HttpBodySubscriberWrapper` have access to the multi exchange.

I had considered this approach, but had dropped it mainly because

1. `MultiExchange::cancelTimer` is a private method, and it would ideally remain so. The timer lifecycle, including cancellation, should be governed by `MultiExchange` itself, not by its subclasses.
2. The current flow makes it easy to trace where cancellation occurs by following method calls: `MultiExchange` →`Exchange::readBodyAsync` → `createResponseSubscriber`, etc. If we invert the logic, identifying where `cancelTimer` is invoked would become less transparent and would rely on IDE assistance.

> That should reduce the amount of changes significantly.

I can relate to that motivation. However, when adapting the code to let `HBSWrapper` subclasses call `cancelTimer`, the only files spared from modification would be `Exchange` and `ExchangeImpl`. So the overall reduction in changed lines would be minor.

> Another possibility is to introduce a noarg protected abstract method in `HttpBodySubscriberWrapper` ...

That approach would face the same downsides as letting subclasses directly call `MultiExchange::cancelTimer`.

> It might need to be called on cancel as well? If not a comment explaining why might be good to have. If it's not called by cancel then maybe the method suggested above could be changed to `onCompletionNotified`.

That was indeed an oversight – fixed in 5621d911944.

@dfuch, how would you prefer I proceed? Should I make `cancelTimer` public and pass it from `HBSWrapper` subclasses, or keep the current design?

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PR Review Comment: https://git.openjdk.org/jdk/pull/27469#discussion_r2461364377