Fixes #7348 - Slow CONNECT request causes NPE

Fixed `HttpClientTest.testCONNECTWithHTTP10()` logic
after changes to fix this issue.

Now a tunneled connection is not put back into the connection pool,
and if applications explicitly want to use it, they must re-enable
fill interest, similarly to what should be done after upgrade+101.

Signed-off-by: Simone Bordet <simone.bordet@gmail.com>

jetty-client/src/main/java/org/eclipse/jetty/client/http/HttpChannelOverHTTP.java

@@ -136,6 +136,7 @@ public void exchangeTerminated(HttpExchange exchange, Result result)
     {
         super.exchangeTerminated(exchange, result);
 
+        String method = exchange.getRequest().getMethod();
         Response response = result.getResponse();
         HttpFields responseHeaders = response.getHeaders();
 
@@ -154,7 +155,7 @@ else if (sender.isShutdown())
                 // HTTP 1.0 must close the connection unless it has
                 // an explicit keep alive or it's a CONNECT method.
                 boolean keepAlive = responseHeaders.contains(HttpHeader.CONNECTION, HttpHeaderValue.KEEP_ALIVE.asString());
-                boolean connect = HttpMethod.CONNECT.is(exchange.getRequest().getMethod());
+                boolean connect = HttpMethod.CONNECT.is(method);
                 if (!keepAlive && !connect)
                     closeReason = "http/1.0";
             }
@@ -174,7 +175,8 @@ else if (sender.isShutdown())
         }
         else
         {
-            if (response.getStatus() == HttpStatus.SWITCHING_PROTOCOLS_101)
+            int status = response.getStatus();
+            if (status == HttpStatus.SWITCHING_PROTOCOLS_101 || isTunnel(method, status))
                 connection.remove();
             else
                 release();
@@ -191,6 +193,11 @@ protected long getMessagesOut()
         return outMessages.longValue();
     }
 
+    boolean isTunnel(String method, int status)
+    {
+        return HttpMethod.CONNECT.is(method) && HttpStatus.isSuccess(status);
+    }
+
     @Override
     public String toString()
     {

jetty-client/src/main/java/org/eclipse/jetty/client/http/HttpReceiverOverHTTP.java

@@ -231,7 +231,7 @@ private boolean parse()
                 // Connection upgrade due to CONNECT + 200, bail out.
                 String method = this.method;
                 this.method = null;
-                if (status == HttpStatus.OK_200 && HttpMethod.CONNECT.is(method))
+                if (getHttpChannel().isTunnel(method, status))
                     return true;
             }
 
@@ -291,8 +291,7 @@ public boolean startResponse(HttpVersion version, int status, String reason)
 
         this.method = exchange.getRequest().getMethod();
         this.status = status;
-        parser.setHeadResponse(HttpMethod.HEAD.is(method) ||
-            (HttpMethod.CONNECT.is(method) && status == HttpStatus.OK_200));
+        parser.setHeadResponse(HttpMethod.HEAD.is(method) || getHttpChannel().isTunnel(method, status));
         exchange.getResponse().version(version).status(status).reason(reason);
 
         return !responseBegin(exchange);

jetty-client/src/test/java/org/eclipse/jetty/client/HttpClientTest.java

@@ -1606,8 +1606,18 @@ public void testCONNECTWithHTTP10(Scenario scenario) throws Exception
 
                 ContentResponse response = listener.get(5, TimeUnit.SECONDS);
                 assertEquals(200, response.getStatus());
+                assertThat(connection, Matchers.instanceOf(HttpConnectionOverHTTP.class));
+                HttpConnectionOverHTTP httpConnection = (HttpConnectionOverHTTP)connection;
+                EndPoint endPoint = httpConnection.getEndPoint();
+                assertTrue(endPoint.isOpen());
+
+                // After a CONNECT+200, this connection is in "tunnel mode",
+                // and applications that want to deal with tunnel bytes must
+                // likely access the underlying EndPoint.
+                // For the purpose of this test, we just re-enable fill interest
+                // so that we can send another clear-text HTTP request.
+                httpConnection.fillInterested();
 
-                // Test that I can send another request on the same connection.
                 request = client.newRequest(host, port);
                 listener = new FutureResponseListener(request);
                 connection.send(request, listener);

jetty-proxy/src/test/java/org/eclipse/jetty/proxy/ForwardProxyTLSServerTest.java

@@ -807,7 +807,6 @@ public void testRequestCompletionDelayed(SslContextFactory.Server proxyTLS) thro
                 @Override
                 public void onSuccess(org.eclipse.jetty.client.api.Request request)
                 {
-                    System.err.println("SIMON: request = " + request);
                     if (HttpMethod.CONNECT.is(request.getMethod()))
                         sleep(250);
                 }