RFR: 8310645: CancelledResponse.java does not use HTTP/2 when testing the HttpClient

[Conor Cleary]

On Tue, 4 Jul 2023 07:40:59 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> **Issue**
>> In CancelledResponse.java the test only checks the HttpClient against HTTP/1.1 when cancelling a BodySubscriber while receiving data. 
>> 
>> **Solution**
>> In the interest of more coverage, a new test has been created which performs the same checks against HTTP/2 to cover the client in the case of a HTTP/2 connection. A new test was created as it makes use of HttpTestServerAdapters to create the test servers. This is different to how this is performed in the original "CancelledResponse" test. There are some minor changes to how the testing is conducted with an element of randomness added to the new test.
>> 
>> As an open question to reviewers, the old test "CancelledResponse" and the new test "CancelledResponse2" could be merged into a single file and the HTTP/1.1 case could be updated to use more canonical testing methods as with "CancelledResponse2". Though there isn't a very pressing need for this and so it has not been included in this PR as of now.
>
> test/jdk/java/net/httpclient/CancelledResponse2.java line 228:
> 
>> 226:                 cancelled.set(true);
>> 227:                 subscription.cancel();
>> 228:                 result.completeExceptionally(new CancelException());
> 
> I believe that's the exception we expect to find in the `HttpResponse`. IIRC the original test was checking for that.

Right, but calling `subscription.cancel()` causes `Stream.cancelImpl()` to be called. That in turn causes the `HttpResponse` (or the variable result in your snippet above) to complete exceptionally with an IOException which has the message "Stream x cancelled". I think that means that the call to `completeExceptionally(new CancelException())` has no effect because `subscription.cancel()` triggers a call to `cancelImpl()`

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PR Review Comment: https://git.openjdk.org/jdk/pull/14625#discussion_r1251778369