Evacuate transient heap when enabling ractors

If the GC has been disabled we need to re-enable it so we can evacuate
the transient heap.

Fixes https://bugs.ruby-lang.org/issues/17985

[Bug #17985] [ruby-core:104260]

Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/ractor.c b/ractor.c
index 372305c256..b5835a8ca6 100644
--- a/ractor.c
+++ b/ractor.c
@@ -1420,9 +1420,15 @@ cancel_single_ractor_mode(void)
     // enable multi-ractor mode
     RUBY_DEBUG_LOG("enable multi-ractor mode", 0);
 
+    VALUE was_disabled = rb_gc_enable();
+
     rb_gc_start();
     rb_transient_heap_evacuate();
 
+    if (was_disabled) {
+        rb_gc_disable();
+    }
+
     ruby_single_main_ractor = NULL;
 
     if (rb_warning_category_enabled_p(RB_WARN_CATEGORY_EXPERIMENTAL)) {