Fix 'require' from a ractor when the required file raises an error

If you catch an error that was raised from a file you required in
a ractor, that error did not have its belonging reset from the main
ractor to the current ractor, so you hit assertion errors in debug
mode.

Author: luke-gruber

ractor.c

@@ -4217,9 +4217,12 @@ rb_ractor_require(VALUE feature)
     rb_ractor_channel_close(ec, crr.ch);
 
     if (crr.exception != Qundef) {
+        ractor_reset_belonging(crr.exception);
         rb_exc_raise(crr.exception);
     }
     else {
+        RUBY_ASSERT(crr.result != Qundef);
+        ractor_reset_belonging(crr.result);
         return crr.result;
     }
 }

test/ruby/test_ractor.rb

@@ -79,6 +79,25 @@ def test_default_thread_group
     end;
   end
 
+  def test_require_raises_and_no_ractor_belonging_issue
+    assert_ractor(<<~'RUBY')
+      require "tempfile"
+      f = Tempfile.new(["file_to_require_from_ractor", ".rb"])
+      f.write("raise 'uh oh'")
+      f.flush
+      err_msg = Ractor.new(f.path) do |path|
+        begin
+          require path
+        rescue RuntimeError => e
+          e.message # had confirm belonging issue here
+        else
+          nil
+        end
+      end.take
+      assert_equal "uh oh", err_msg
+    RUBY
+  end
+
   def assert_make_shareable(obj)
     refute Ractor.shareable?(obj), "object was already shareable"
     Ractor.make_shareable(obj)