fix: time out on the client when the driver stops responding

playwright/src/main/java/com/microsoft/playwright/impl/Connection.java

@@ -29,6 +29,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.TimeUnit;
 
 import static com.microsoft.playwright.impl.Serialization.gson;
 import static java.lang.System.currentTimeMillis;
@@ -39,7 +40,7 @@
   String method;
   JsonObject params;
   JsonElement result;
   SerializedError error;
   JsonObject errorDetails;
   JsonArray log;
 
@@ -69,6 +70,7 @@
   private final Map<String, WaitableResult<JsonElement>> callbacks = new HashMap<>();
   private String title;
   private boolean titleReported = false;
+  private static final long DRIVER_RESPONSE_GRACE_MS = 10_000;
   private static final boolean isLogging;
   static {
     String debug = System.getenv("DEBUG");
@@ -145,7 +147,19 @@
   }
 
   public JsonElement sendMessage(String guid, String method, JsonObject params, Double timeout) {
-    return root.runUntil(() -> {}, internalSendMessage(guid, method, params, timeout, true, true));
+    WaitableResult<JsonElement> result = internalSendMessage(guid, method, params, timeout, true, true);
+    if (timeout == null || timeout == 0) {
+      return root.runUntil(() -> {}, result);
+    }
+    // The driver enforces the timeout, but the driver itself may hang.
+    long deadline = System.nanoTime() + TimeUnit.MILLISECONDS.toNanos(timeout.longValue() + DRIVER_RESPONSE_GRACE_MS);
+    while (!result.isDone()) {
+      if (!processOneMessage() && System.nanoTime() - deadline > 0) {
+        result.completeExceptionally(new TimeoutError("Timeout " + timeout.longValue() + "ms exceeded while waiting for the driver to respond to " +
+          method + ". The driver is not responding."));
+      }
+    }
+    return result.get();
   }
 
   public WaitableResult<JsonElement> sendMessageAsync(String guid, String method, JsonObject params) {
@@ -232,14 +246,15 @@
     objects.remove(guid);
   }
 
-  void processOneMessage() {
+  boolean processOneMessage() {
     JsonObject message = transport.poll(Duration.ofMillis(10));
     if (message == null) {
-      return;
+      return false;
     }
     Gson gson = gson();
     Message messageObj = gson.fromJson(message, Message.class);
     dispatch(messageObj);
+    return true;
   }
 
   private static String formatCallLog(JsonArray log) {

playwright/src/test/java/com/microsoft/playwright/TestUnresponsiveDriver.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.microsoft.playwright;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.condition.EnabledForJreRange;
+import org.junit.jupiter.api.condition.JRE;
+import org.junit.jupiter.api.condition.OS;
+
+import java.lang.reflect.Field;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class TestUnresponsiveDriver {
+  @Test
+  @DisabledOnOs(OS.WINDOWS)
+  @EnabledForJreRange(min = JRE.JAVA_9)
+  void shouldThrowTimeoutErrorWhenDriverStopsResponding() throws Exception {
+    try (Playwright playwright = Playwright.create()) {
+      Browser browser = Utils.getBrowserTypeFromEnv(playwright).launch(TestBase.createLaunchOptions());
+      Page page = browser.newPage();
+      long pid = driverPid(playwright);
+      signal("STOP", pid);
+      try {
+        long start = System.nanoTime();
+        TimeoutError e = assertThrows(TimeoutError.class,
+          () -> page.waitForFunction("() => false", null, new Page.WaitForFunctionOptions().setTimeout(100)));
+        long elapsedMs = (System.nanoTime() - start) / 1_000_000;
+        assertTrue(e.getMessage().contains("Timeout 100ms exceeded while waiting for the driver to respond to waitForFunction"), e.getMessage());
+        assertTrue(elapsedMs < 20_000, "elapsed: " + elapsedMs);
+      } finally {
+        signal("CONT", pid);
+      }
+      // The driver's late reply to the abandoned call must not break the connection.
+      assertEquals(2, page.evaluate("1 + 1"));
+    }
+  }
+
+  private static long driverPid(Playwright playwright) throws Exception {
+    Field field = playwright.getClass().getDeclaredField("driverProcess");
+    field.setAccessible(true);
+    // Called via reflection as the tests are compiled with JDK 8 on CI.
+    return (long) Process.class.getMethod("pid").invoke(field.get(playwright));
+  }
+
+  private static void signal(String signal, long pid) throws Exception {
+    Process kill = new ProcessBuilder("kill", "-" + signal, Long.toString(pid)).inheritIO().start();
+    assertEquals(0, kill.waitFor());
+  }
+}