fix: limit number of tracked unused Deferred objects to 10 (#189)

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

@@ -104,7 +104,7 @@ class ChannelOwner {
       @Override
       protected void finalize() {
         if (constructionStackTrace != null) {
-          connection.unusedDeferredObjects.add(constructionStackTrace);
+          connection.addUnusedDeferredObject(constructionStackTrace);
         }
       }
     };

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

@@ -20,9 +20,7 @@ import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.microsoft.playwright.PlaywrightException;
 
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
+import java.io.*;
 import java.time.Duration;
 import java.util.*;
 
@@ -56,7 +54,7 @@ public class Connection {
   private final Root root;
   private int lastId = 0;
   private final Map<Integer, WaitableResult<JsonElement>> callbacks = new HashMap<>();
-  final Deque<Exception> unusedDeferredObjects = new ArrayDeque<>();
+  private final Deque<Exception> unusedDeferredObjects = new ArrayDeque<>();
 
   class Root extends ChannelOwner {
     Root(Connection connection) {
@@ -267,4 +265,19 @@ public class Connection {
       unusedDeferredObjects.removeLast();
     }
   }
+
+  void checkNoUnusedDeferredObjects() {
+    if (unusedDeferredObjects.isEmpty()) {
+      return;
+    }
+    List<String> chunks = new ArrayList<>();
+    chunks.add("Method get() has not been called on some Deferred<> objects. This indicates a " +
+      "bug in the client code. Here are some stack traces where such objects were constructed");
+    for (Exception e : unusedDeferredObjects) {
+      StringWriter writer = new StringWriter();
+      e.printStackTrace(new PrintWriter(writer));
+      chunks.add(writer.toString());
+    }
+    throw new PlaywrightException(String.join("\n", chunks));
+  }
 }

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

@@ -108,17 +108,6 @@ public class PlaywrightImpl extends ChannelOwner implements Playwright {
       System.err.println("WARNING: Timed out while waiting for driver process to exit");
     }
 
-    if (connection.unusedDeferredObjects.isEmpty()) {
-      return;
-    }
-    List<String> chunks = new ArrayList<>();
-    chunks.add("Method get() has not been called on some Deferred<> objects. This indicates a " +
-      "bug in the client code. Here are some stack traces where such objects were constructed");
-    for (Exception e : connection.unusedDeferredObjects) {
-      StringWriter writer = new StringWriter();
-      e.printStackTrace(new PrintWriter(writer));
-      chunks.add(writer.toString());
-    }
-    throw new PlaywrightException(String.join("\n", chunks));
+    connection.checkNoUnusedDeferredObjects();
   }
 }