8372409: java/net/httpclient/http3/H3MultipleConnectionsToSameHost.java timed out during warmup

Reviewed-by: djelinski

src/java.net.http/share/classes/jdk/internal/net/http/Http3Connection.java

@@ -561,7 +561,28 @@ public final class Http3Connection implements AutoCloseable {
         if (debug.on()) debug.log("Reference h3 stream: " + streamId);
         client.client.h3StreamReference();
         exchanges.put(streamId, exchange);
-        exchange.start();
+        // It's possible that the connection will have been closed
+        // by the time we reach here.
+        // We need to double-check that the connection is still opened
+        // after having put the exchange to the exchanges map.
+        if (isOpen()) {
+            // only start the exchange if the connection is
+            // still open
+            exchange.start();
+        } else {
+            // Otherwise mark the exchange as unprocessed since we haven't
+            // sent the headers yet and the connection got closed
+            // before we started the exchange.
+            TerminationCause tc = quicConnection.terminationCause();
+            if (Log.http3()) {
+                Log.logHttp3("HTTP/3 exchange for {0}/streamId={1} unprocessed due to {2}",
+                        quicConnectionTag(), Long.toString(streamId), tc.getCloseCause());
+            }
+            exchange.exchange.markUnprocessedByPeer();
+            exchange.cancelImpl(tc.getCloseCause(),
+                    Http3Error.fromCode(tc.getCloseCode()).orElse(H3_NO_ERROR));
+        }
+        // OK to return the exchange even if already closed
         return exchange;
     }
 

test/jdk/java/net/httpclient/http3/H3MultipleConnectionsToSameHost.java

@@ -23,7 +23,7 @@
 
 /*
  * @test id=with-continuations
- * @bug 8087112
+ * @bug 8087112 8372409
  * @requires os.family != "windows" | ( os.name != "Windows 10" & os.name != "Windows Server 2016"
  *                                      & os.name != "Windows Server 2019" )
  * @library /test/lib /test/jdk/java/net/httpclient/lib
@@ -46,7 +46,7 @@
  */
 /*
  * @test id=without-continuations
- * @bug 8087112
+ * @bug 8087112 8372409
  * @requires os.family == "windows" & ( os.name == "Windows 10" | os.name == "Windows Server 2016"
  *                                     | os.name == "Windows Server 2019" )
  * @library /test/lib /test/jdk/java/net/httpclient/lib
@@ -71,7 +71,7 @@
  */
 /*
  * @test id=useNioSelector
- * @bug 8087112
+ * @bug 8087112 8372409
  * @library /test/lib /test/jdk/java/net/httpclient/lib
  * @build jdk.test.lib.net.SimpleSSLContext
  *        jdk.httpclient.test.lib.http2.Http2TestServer
@@ -96,7 +96,7 @@
  */
 /*
  * @test id=reno-cc
- * @bug 8087112
+ * @bug 8087112 8372409
  * @library /test/lib /test/jdk/java/net/httpclient/lib
  * @build jdk.test.lib.net.SimpleSSLContext
  *        jdk.httpclient.test.lib.http2.Http2TestServer