Prevent unhandled task exceptions (#950)

* Prevent unhandled task exceptions

* Remove double blank line

Author: ggeurts

lib/PuppeteerSharp/Page.cs

@@ -79,11 +79,18 @@ private Page(
             _ignoreHTTPSErrors = ignoreHTTPSErrors;
 
             _screenshotTaskQueue = screenshotTaskQueue;
-            target.CloseTask.ContinueWith((arg) =>
+            
+            _ = target.CloseTask.ContinueWith((arg) =>
             {
-                Close?.Invoke(this, EventArgs.Empty);
-                IsClosed = true;
-                _closeCompletedTcs.TrySetResult(true);
+                try
+                {
+                    Close?.Invoke(this, EventArgs.Empty);
+                }
+                finally
+                {
+                    IsClosed = true;
+                    _closeCompletedTcs.TrySetResult(true);
+                }
             });
 
             Client.MessageReceived += Client_MessageReceived;
@@ -1104,7 +1111,7 @@ public Task CloseAsync(PageCloseOptions options = null)
                     return Client.Connection.SendAsync("Target.closeTarget", new TargetCloseTargetRequest
                     {
                         TargetId = Target.TargetId
-                    }).ContinueWith((task) => Target.CloseTask);
+                    }).ContinueWith(task => Target.CloseTask);
                 }
             }
 

lib/PuppeteerSharp/Target.cs

@@ -13,8 +13,8 @@ public class Target
     {
         #region Private members
         private TargetInfo _targetInfo;
-        private readonly string _targetId;
         private readonly Func<TargetInfo, Task<CDPSession>> _sessionFactory;
+        private readonly TaskCompletionSource<bool> _initializedTaskWrapper = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
         #endregion
 
         internal bool IsInitialized;
@@ -25,24 +25,24 @@ internal Target(
             BrowserContext browserContext)
         {
             _targetInfo = targetInfo;
-            _targetId = targetInfo.TargetId;
             _sessionFactory = sessionFactory;
             BrowserContext = browserContext;
             PageTask = null;
 
-            InitilizedTaskWrapper = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
-            InitilizedTaskWrapper.Task.ContinueWith(async initializedTask =>
+            _ = _initializedTaskWrapper.Task.ContinueWith(async initializedTask =>
             {
                 var success = initializedTask.Result;
                 if (!success)
                 {
                     return;
                 }
-                if (Opener == null || Opener.PageTask == null || Type != TargetType.Page)
+
+                var openerPageTask = Opener?.PageTask;
+                if (openerPageTask == null || Type != TargetType.Page)
                 {
                     return;
                 }
-                var openerPage = await Opener.PageTask.ConfigureAwait(false);
+                var openerPage = await openerPageTask.ConfigureAwait(false);
                 if (!openerPage.HasPopupEventListeners)
                 {
                     return;
@@ -56,7 +56,7 @@ internal Target(
 
             if (IsInitialized)
             {
-                InitilizedTaskWrapper.TrySetResult(true);
+                _initializedTaskWrapper.TrySetResult(true);
             }
         }
 
@@ -97,8 +97,7 @@ internal Target(
         /// </summary>
         public BrowserContext BrowserContext { get; }
 
-        internal Task<bool> InitializedTask => InitilizedTaskWrapper.Task;
-        internal TaskCompletionSource<bool> InitilizedTaskWrapper { get; }
+        internal Task<bool> InitializedTask => _initializedTaskWrapper.Task;
         internal Task CloseTask => CloseTaskWrapper.Task;
         internal TaskCompletionSource<bool> CloseTaskWrapper { get; }
         internal Task<Page> PageTask { get; set; }
@@ -132,7 +131,7 @@ internal void TargetInfoChanged(TargetInfo targetInfo)
             if (!IsInitialized && (_targetInfo.Type != TargetType.Page || _targetInfo.Url != string.Empty))
             {
                 IsInitialized = true;
-                InitilizedTaskWrapper.TrySetResult(true);
+                _initializedTaskWrapper.TrySetResult(true);
                 return;
             }