Move feature deletion from GC mark to `autoload_delete`. (#5912)

1 files changed, 10 insertions, 6 deletions

diff --git a/variable.c b/variable.c
index 37359fe55a..6360dd5476 100644
--- a/variable.c
+++ b/variable.c
@@ -2176,11 +2176,6 @@ autoload_data_mark(void *ptr)
 
     rb_gc_mark_movable(p->feature);
     rb_gc_mark_movable(p->mutex);
-
-    // Allow GC to free us if no modules refer to this via autoload_const.autoload_data
-    if (ccan_list_empty(&p->constants)) {
-        rb_hash_delete(autoload_features, p->feature);
-    }
 }
 
 static void
@@ -2422,7 +2417,10 @@ autoload_delete(VALUE module, ID name)
         /* Qfalse can indicate already deleted */
         if (load != Qfalse) {
             struct autoload_const *autoload_const;
-            get_autoload_data((VALUE)load, &autoload_const);
+            struct autoload_data *autoload_data = get_autoload_data((VALUE)load, &autoload_const);
+
+            VM_ASSERT(autoload_data);
+            VM_ASSERT(!ccan_list_empty(&autoload_data->constants));
 
             /*
              * we must delete here to avoid "already initialized" warnings
@@ -2431,6 +2429,10 @@ autoload_delete(VALUE module, ID name)
              */
             ccan_list_del_init(&autoload_const->cnode);
 
+            if (ccan_list_empty(&autoload_data->constants)) {
+                rb_hash_delete(autoload_features, autoload_data->feature);
+            }
+
             // If the autoload table is empty, we can delete it.
             if (table->num_entries == 0) {
                 name = autoload;
@@ -2650,6 +2652,8 @@ autoload_apply_constants(VALUE _arguments)
         struct autoload_const *autoload_const;
         struct autoload_const *next;
 
+        // We use safe iteration here because `autoload_const_set` will eventually invoke `autoload_delete` which will remove the constant from the linked list. In theory, once the `autoload_data->constants` linked list is empty, we can remove it.
+
         // Iterate over all constants and assign them:
         ccan_list_for_each_safe(&arguments->autoload_data->constants, autoload_const, next, cnode) {
             if (autoload_const->value != Qundef) {