From 6eeeb07e273c069273bcd930a612a0c960668a11 Mon Sep 17 00:00:00 2001
From: nagachika <nagachika@ruby-lang.org>
Date: Sat, 9 May 2026 15:09:56 +0900
Subject: merge revision(s) f315d250b44e75a1a69f4a05b293dcc701377689: [Backport
 #21947]

	[PATCH] [ruby/timeout] Compatibility with Fiber scheduler. (https://github.com/ruby/timeout/pull/97)

	[Bug #21947]

	https://github.com/ruby/timeout/commit/55d7c84b50
---
 lib/timeout.rb       | 28 ++++++++++----------
 test/test_timeout.rb | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 version.h            |  2 +-
 3 files changed, 89 insertions(+), 14 deletions(-)

diff --git a/lib/timeout.rb b/lib/timeout.rb
index 4fd1fa46da..6218b1969e 100644
--- a/lib/timeout.rb
+++ b/lib/timeout.rb
@@ -171,20 +171,22 @@ module Timeout
     message ||= "execution expired"
 
     if Fiber.respond_to?(:current_scheduler) && (scheduler = Fiber.current_scheduler)&.respond_to?(:timeout_after)
-      return scheduler.timeout_after(sec, klass || Error, message, &block)
-    end
-
-    Timeout.ensure_timeout_thread_created
-    perform = Proc.new do |exc|
-      request = Request.new(Thread.current, sec, exc, message)
-      QUEUE_MUTEX.synchronize do
-        QUEUE << request
-        CONDVAR.signal
+      perform = Proc.new do |exc|
+        scheduler.timeout_after(sec, exc, message, &block)
       end
-      begin
-        return yield(sec)
-      ensure
-        request.finished
+    else
+      Timeout.ensure_timeout_thread_created
+      perform = Proc.new do |exc|
+        request = Request.new(Thread.current, sec, exc, message)
+        QUEUE_MUTEX.synchronize do
+          QUEUE << request
+          CONDVAR.signal
+        end
+        begin
+          return yield(sec)
+        ensure
+          request.finished
+        end
       end
     end
 
diff --git a/test/test_timeout.rb b/test/test_timeout.rb
index 01156867b0..7809fdd68f 100644
--- a/test/test_timeout.rb
+++ b/test/test_timeout.rb
@@ -274,4 +274,77 @@ class TestTimeout < Test::Unit::TestCase
       }.join
     end;
   end
+
+  if Fiber.respond_to?(:current_scheduler)
+    # Stubs Fiber.current_scheduler for the duration of the block, then restores it.
+    def with_mock_scheduler(mock)
+      original = Fiber.method(:current_scheduler)
+      Fiber.define_singleton_method(:current_scheduler) { mock }
+      begin
+        yield
+      ensure
+        Fiber.define_singleton_method(:current_scheduler, original)
+      end
+    end
+
+    def test_fiber_scheduler_delegates_to_timeout_after
+      received = nil
+      mock = Object.new
+      mock.define_singleton_method(:timeout_after) do |sec, exc, msg, &blk|
+        received = [sec, exc, msg]
+        blk.call(sec)
+      end
+
+      with_mock_scheduler(mock) do
+        assert_equal :ok, Timeout.timeout(5) { :ok }
+      end
+
+      assert_equal 5, received[0]
+      assert_instance_of Timeout::ExitException, received[1], "scheduler should receive an ExitException instance when no klass given"
+      assert_equal "execution expired", received[2]
+    end
+
+    def test_fiber_scheduler_delegates_to_timeout_after_with_custom_exception
+      custom_error = Class.new(StandardError)
+      received = nil
+      mock = Object.new
+      mock.define_singleton_method(:timeout_after) do |sec, exc, msg, &blk|
+        received = [sec, exc, msg]
+        blk.call(sec)
+      end
+
+      with_mock_scheduler(mock) do
+        assert_equal :ok, Timeout.timeout(5, custom_error, "custom message") { :ok }
+      end
+
+      assert_equal [5, custom_error, "custom message"], received
+    end
+
+    def test_fiber_scheduler_timeout_raises_timeout_error
+      mock = Object.new
+      mock.define_singleton_method(:timeout_after) do |sec, exc, msg, &blk|
+        raise exc  # simulate timeout firing
+      end
+
+      with_mock_scheduler(mock) do
+        assert_raise(Timeout::Error) do
+          Timeout.timeout(5) { :should_not_reach }
+        end
+      end
+    end
+
+    def test_fiber_scheduler_timeout_raises_custom_error
+      custom_error = Class.new(StandardError)
+      mock = Object.new
+      mock.define_singleton_method(:timeout_after) do |sec, exc, msg, &blk|
+        raise exc, msg
+      end
+
+      with_mock_scheduler(mock) do
+        assert_raise_with_message(custom_error, "custom message") do
+          Timeout.timeout(5, custom_error, "custom message") { :should_not_reach }
+        end
+      end
+    end
+  end
 end
diff --git a/version.h b/version.h
index 46182a0b6d..0796278b85 100644
--- a/version.h
+++ b/version.h
@@ -11,7 +11,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 9
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 85
+#define RUBY_PATCHLEVEL 86
 
 #include "ruby/version.h"
 #include "ruby/internal/abi.h"
-- 
cgit v1.2.3