Don't treat AR hashes the same way as st hashes

We don't want to lift all AR hashes to st tables, so lets update
references in AR hashes.

Author: tenderlove

gc.c

@@ -7537,7 +7537,7 @@ hash_foreach_replace(st_data_t key, st_data_t value, st_data_t argp, int error)
     if(gc_object_moved_p(objspace, (VALUE)value)) {
 	return ST_REPLACE;
     }
-    return ST_CHECK;
+    return ST_CONTINUE;
 }
 
 static void
@@ -7558,7 +7558,7 @@ rb_gc_update_tbl_refs(st_table *ptr)
 static void
 gc_ref_update_hash(rb_objspace_t * objspace, VALUE v)
 {
-    gc_update_table_refs(objspace, rb_hash_tbl_raw(v));
+    rb_hash_stlike_foreach_with_replace(v, hash_foreach_replace, hash_replace_ref, (st_data_t)objspace);
 }
 
 void rb_update_st_references(struct st_table *ht)

hash.c

@@ -781,7 +781,7 @@ ar_add_direct_with_hash(VALUE hash, st_data_t key, st_data_t val, st_hash_t hash
 }
 
 static int
-ar_foreach(VALUE hash, int (*func)(ANYARGS), st_data_t arg)
+ar_general_foreach(VALUE hash, int (*func)(ANYARGS), st_update_callback_func *replace, st_data_t arg)
 {
     if (RHASH_AR_TABLE_SIZE(hash) > 0) {
         unsigned i, bound = RHASH_AR_TABLE_BOUND(hash);
@@ -797,9 +797,22 @@ ar_foreach(VALUE hash, int (*func)(ANYARGS), st_data_t arg)
               case ST_CONTINUE:
                 break;
               case ST_CHECK:
-              case ST_REPLACE:
               case ST_STOP:
                 return 0;
+              case ST_REPLACE:
+                if (replace) {
+                    VALUE key;
+                    VALUE value;
+
+                    key = cur_entry->key;
+                    value = cur_entry->record;
+                    retval = (*replace)(&key, &value, arg, TRUE);
+
+                    ar_table_entry *entry = RHASH_AR_TABLE_REF(hash, i);
+                    entry->key = key;
+                    entry->record = value;
+                }
+                break;
               case ST_DELETE:
                 ar_clear_entry(RHASH_AR_TABLE_REF(hash, i));
                 RHASH_AR_TABLE_SIZE_DEC(hash);
@@ -810,6 +823,18 @@ ar_foreach(VALUE hash, int (*func)(ANYARGS), st_data_t arg)
     return 0;
 }
 
+static int
+ar_foreach_with_replace(VALUE hash, int (*func)(ANYARGS), st_update_callback_func *replace, st_data_t arg)
+{
+    return ar_general_foreach(hash, func, replace, arg);
+}
+
+static int
+ar_foreach(VALUE hash, int (*func)(ANYARGS), st_data_t arg)
+{
+    return ar_general_foreach(hash, func, NULL, arg);
+}
+
 static int
 ar_foreach_check(VALUE hash, int (*func)(ANYARGS), st_data_t arg,
                      st_data_t never)
@@ -1259,6 +1284,17 @@ rb_hash_stlike_foreach(VALUE hash, int (*func)(ANYARGS), st_data_t arg)
     }
 }
 
+int
+rb_hash_stlike_foreach_with_replace(VALUE hash, int (*func)(ANYARGS), st_update_callback_func *replace, st_data_t arg)
+{
+    if (RHASH_AR_TABLE_P(hash)) {
+        return ar_foreach_with_replace(hash, func, replace, arg);
+    }
+    else {
+        return st_foreach_with_replace(RHASH_ST_TABLE(hash), func, replace, arg);
+    }
+}
+
 static VALUE
 hash_foreach_call(VALUE arg)
 {

internal.h

@@ -1566,6 +1566,7 @@ void rb_hash_bulk_insert(long, const VALUE *, VALUE);
 int rb_hash_stlike_lookup(VALUE hash, st_data_t key, st_data_t *pval);
 int rb_hash_stlike_delete(VALUE hash, st_data_t *pkey, st_data_t *pval);
 int rb_hash_stlike_foreach(VALUE hash, int (*func)(ANYARGS), st_data_t arg);
+int rb_hash_stlike_foreach_with_replace(VALUE hash, int (*func)(ANYARGS), st_update_callback_func *replace, st_data_t arg);
 int rb_hash_stlike_update(VALUE hash, st_data_t key, st_update_callback_func func, st_data_t arg);
 
 /* inits.c */