From bcc34ee7b68c69dc7cdbc2f0654eb3f9dcd27d65 Mon Sep 17 00:00:00 2001
From: Edwin Wu <edwinwu@google.com>
Date: Mon, 28 Jul 2025 18:19:53 -0700
Subject: [PATCH] Make timer queue run on background queue

PiperOrigin-RevId: 788236523
---
 internal/platform/implementation/apple/timer.mm | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/internal/platform/implementation/apple/timer.mm b/internal/platform/implementation/apple/timer.mm
index e638c1cf..86e68c7f 100644
--- a/internal/platform/implementation/apple/timer.mm
+++ b/internal/platform/implementation/apple/timer.mm
@@ -50,8 +50,10 @@ bool Timer::Create(int delay, int interval, absl::AnyInvocable<void()> callback)
   uint64_t intervalInNanoseconds = interval == 0 ? DISPATCH_TIME_FOREVER : interval * NSEC_PER_MSEC;
   callback_ = std::move(callback);
 
+  // Run the timer on a background queue to avoid deadlocking the main thread,
+  // which may be blocked waiting for a future to complete.
   timer_ = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, /*handle=*/0, /*mask=*/0,
-                                  dispatch_get_main_queue());
+                                  dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0));
 
   dispatch_source_set_event_handler(timer_, ^{
     absl::AnyInvocable<void()> callback_to_run = nullptr;