RFR: 8304701: Request with timeout aborts later in-flight request on HTTP/1.1 cxn

[Conor Cleary]

On Thu, 16 Nov 2023 13:11:35 GMT, Conor Cleary <ccleary at openjdk.org> wrote:

> **Problem**
> When using HTTP/1.1 with HttpClient, it was observed that requests configured with timeouts at build time fail with a HttpTimeoutException when they are redirected to a separate URI by a server (status code 3xx on first response). What should happen is that the second request response (so after receiving a 3xx code) clears restarts the timer intially set. However, when `responseTimerEvent` is registered for the first time, it is not unregistered and cleared before starting a second timer.
> 
> **Solution**
> This fix addresses the issue by calling `cancelTimer()` in `MultiExchange.java` whenever the `newRequest` reference is set to a non-null value after calling `responseFilters(response)` on the initial response received. This occurs in the case where a status code 3xx is received in the initial response. When `cancelTimer()` is called, it now unreferences `responseTimerEvent` after cancellation operations take place.
> 
> While the fix for the issue was relatively straight forward, the regression test is less so. I would point to to the comment located in `RedirectTimeoutTest:L119` for an explanation of the testing method.

test/jdk/java/net/httpclient/RedirectTimeoutTest.java line 118:

> 116:             if (version.equals(HTTP_2))
> 117:                 client.send(HttpRequest.newBuilder(h2WarmupUri).HEAD().build(), HttpResponse.BodyHandlers.discarding());
> 118:             /*

Test Comment mentioned in PR description

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PR Review Comment: https://git.openjdk.org/jdk/pull/16689#discussion_r1395674986