merge revision(s) 5c7af72304d0ad33cd3f21b24a4bc44e8acd5b2c,d650b17686d49c2ce8e6a87039861154e93d4621: [Backport #18497]

	Assuming EXIT_SUCCESS equals 0 is not portable

	---
	 test/ruby/test_fiber.rb | 6 +++---
	 1 file changed, 3 insertions(+), 3 deletions(-)

	`rb_fiber_terminate` must not return [Bug #18497]

	In a forked process from a fiber, the fiber becomes the only
	fiber, `fiber_switch` does nothing as there is no other fibers,
	`rb_fiber_terminate` does not terminate the fiber.  In that case,
	reaches the end of `fiber_entry` finaly, which is declared as
	"COROUTINE" and should never return.
	---
	 cont.c                     |  3 ++-
	 eval_intern.h              |  2 +-
	 test/fiber/test_process.rb | 15 +++++++++++++++
	 test/ruby/test_fiber.rb    |  5 +++++
	 4 files changed, 23 insertions(+), 2 deletions(-)

5 files changed, 27 insertions, 6 deletions

diff --git a/cont.c b/cont.c
index 4b18ddda67..2d33ff4025 100644
--- a/cont.c
+++ b/cont.c
@@ -2039,7 +2039,7 @@ rb_fiber_set_scheduler(VALUE klass, VALUE scheduler)
     return rb_fiber_scheduler_set(scheduler);
 }
 
-static void rb_fiber_terminate(rb_fiber_t *fiber, int need_interrupt, VALUE err);
+NORETURN(static void rb_fiber_terminate(rb_fiber_t *fiber, int need_interrupt, VALUE err));
 
 void
 rb_fiber_start(rb_fiber_t *fiber)
@@ -2408,6 +2408,7 @@ rb_fiber_terminate(rb_fiber_t *fiber, int need_interrupt, VALUE error)
         fiber_switch(next_fiber, -1, &error, RB_NO_KEYWORDS, NULL, false);
     else
         fiber_switch(next_fiber, 1, &value, RB_NO_KEYWORDS, NULL, false);
+    ruby_stop(0);
 }
 
 static VALUE
diff --git a/eval_intern.h b/eval_intern.h
index 266a84601e..78feb241a4 100644
--- a/eval_intern.h
+++ b/eval_intern.h
@@ -283,7 +283,7 @@ VALUE rb_make_exception(int argc, const VALUE *argv);
 
 NORETURN(void rb_method_name_error(VALUE, VALUE));
 
-void rb_fiber_start(rb_fiber_t*);
+NORETURN(void rb_fiber_start(rb_fiber_t*));
 
 NORETURN(void rb_print_undef(VALUE, ID, rb_method_visibility_t));
 NORETURN(void rb_print_undef_str(VALUE, VALUE));
diff --git a/test/fiber/test_process.rb b/test/fiber/test_process.rb
index c6583cac9b..a5990be204 100644
--- a/test/fiber/test_process.rb
+++ b/test/fiber/test_process.rb
@@ -33,4 +33,19 @@ class TestFiberProcess < Test::Unit::TestCase
       end
     end.join
   end
+
+  def test_fork
+    omit 'fork not supported' unless Process.respond_to?(:fork)
+    Thread.new do
+      scheduler = Scheduler.new
+      Fiber.set_scheduler scheduler
+
+      Fiber.schedule do
+        pid = Process.fork {}
+        Process.wait(pid)
+
+        assert_predicate $?, :success?
+      end
+    end.join
+  end
 end
diff --git a/test/ruby/test_fiber.rb b/test/ruby/test_fiber.rb
index 3aad5dd09c..e4b7322bd9 100644
--- a/test/ruby/test_fiber.rb
+++ b/test/ruby/test_fiber.rb
@@ -396,7 +396,7 @@ class TestFiber < Test::Unit::TestCase
                 Fiber.new {}.transfer
                 Fiber.new { Fiber.yield }
               end
-              exit!(0)
+              exit!(true)
             end
           }.transfer
           _, status = Process.waitpid2(xpid)
@@ -405,8 +405,13 @@ class TestFiber < Test::Unit::TestCase
       end.resume
     end
     pid, status = Process.waitpid2(pid)
-    assert_equal(0, status.exitstatus, bug5700)
-    assert_equal(false, status.signaled?, bug5700)
+    assert_not_predicate(status, :signaled?, bug5700)
+    assert_predicate(status, :success?, bug5700)
+
+    pid = Fiber.new {fork}.resume
+    pid, status = Process.waitpid2(pid)
+    assert_not_predicate(status, :signaled?)
+    assert_predicate(status, :success?)
   end
 
   def test_exit_in_fiber
diff --git a/version.h b/version.h
index 06df6ce639..ac08e82e8b 100644
--- a/version.h
+++ b/version.h
@@ -11,7 +11,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 0
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 9
+#define RUBY_PATCHLEVEL 10
 
 #define RUBY_RELEASE_YEAR 2022
 #define RUBY_RELEASE_MONTH 1