From ee445f21976e9d40166e59ebd2866e4fa2a9ff10 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Sun, 19 Mar 2023 15:54:35 +0600
Subject: [PATCH] Fixed dispatcher for macOS

---
 native/Avalonia.Native/src/OSX/platformthreading.mm | 4 +---
 src/Avalonia.Base/Threading/Dispatcher.Queue.cs     | 8 +++++++-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/native/Avalonia.Native/src/OSX/platformthreading.mm b/native/Avalonia.Native/src/OSX/platformthreading.mm
index b727b9a6cf..d2d7a365a6 100644
--- a/native/Avalonia.Native/src/OSX/platformthreading.mm
+++ b/native/Avalonia.Native/src/OSX/platformthreading.mm
@@ -79,13 +79,11 @@ static double distantFutureInterval = (double)50*365*24*3600;
         bool signaled;
         @synchronized (self) {
             signaled = self->_signaled;
+            self->_signaled = false;
         }
         if(signaled)
         {
             self->_events->Signaled();
-            @synchronized (self) {
-                self->_signaled = false;
-            }
         }
     });
     CFRunLoopAddObserver(CFRunLoopGetMain(), _observer, kCFRunLoopCommonModes);
diff --git a/src/Avalonia.Base/Threading/Dispatcher.Queue.cs b/src/Avalonia.Base/Threading/Dispatcher.Queue.cs
index 9db8c5e8c0..0c5414e6d1 100644
--- a/src/Avalonia.Base/Threading/Dispatcher.Queue.cs
+++ b/src/Avalonia.Base/Threading/Dispatcher.Queue.cs
@@ -124,7 +124,13 @@ public partial class Dispatcher
             else if (_pendingInputImpl?.CanQueryPendingInput == true)
             {
                 if (!_pendingInputImpl.HasPendingInput)
-                    ExecuteJob(job);
+                {
+                    // On platforms like macOS HasPendingInput check might trigger a timer
+                    // which would result in reentrancy here, so we check if the job 
+                    // hasn't been executed yet
+                    if (job.Status == DispatcherOperationStatus.Pending)
+                        ExecuteJob(job);
+                }
                 else
                 {
                     RequestBackgroundProcessing();