Compacting the heap can cause GC, so disable it

When we compact the heap, various st tables are updated, particularly
the table that contains the object id map.  Updating an st table can
cause a GC to occur, and we need to prevent any GC from happening while
moving or updating references.

1 files changed, 1 insertions, 1 deletions

diff --git a/gc.c b/gc.c
index 6fcdf2a53c..97133e6a23 100644
--- a/gc.c
+++ b/gc.c
@@ -8554,6 +8554,7 @@ gc_compact_after_gc(rb_objspace_t *objspace, int use_toward_empty, int use_doubl
     }
 
     VALUE moved_list;
+    VALUE disabled = rb_gc_disable();
 
     if (use_toward_empty) {
         moved_list = gc_compact_heap(objspace, compare_free_slots);
@@ -8563,7 +8564,6 @@ gc_compact_after_gc(rb_objspace_t *objspace, int use_toward_empty, int use_doubl
     }
     heap_eden->freelist = NULL;
 
-    VALUE disabled = rb_gc_disable();
     gc_update_references(objspace);
     if (!RTEST(disabled)) rb_gc_enable();