Revert "[Bug #21331] Prohibit modification during stlike loop"

This reverts commit bb180b8, which
caused "malloc during GC" error on wasm.

Author: nobu

hash.c

@@ -880,7 +880,7 @@ ar_general_foreach(VALUE hash, st_foreach_check_callback_func *func, st_update_c
                 return 0;
               case ST_REPLACE:
                 if (replace) {
-                    (*replace)(&key, &val, arg, TRUE);
+                    retval = (*replace)(&key, &val, arg, TRUE);
 
                     // TODO: pair should be same as pair before.
                     pair = RHASH_AR_TABLE_REF(hash, i);
@@ -1404,84 +1404,26 @@ hash_foreach_ensure(VALUE hash)
     return 0;
 }
 
-struct hash_stlike_foreach_arg {
-    VALUE hash;
-    st_foreach_callback_func *func;
-    VALUE arg;
-};
-
-static VALUE
-hash_stlike_foreach_call(VALUE args)
+int
+rb_hash_stlike_foreach(VALUE hash, st_foreach_callback_func *func, st_data_t arg)
 {
-    struct hash_stlike_foreach_arg *argp = (void *)args;
-    VALUE hash = argp->hash;
-    st_foreach_callback_func *func = argp->func;
-    VALUE arg = argp->arg;
-    int ret;
-
     if (RHASH_AR_TABLE_P(hash)) {
-        ret = ar_foreach(hash, func, arg);
+        return ar_foreach(hash, func, arg);
     }
     else {
-        ret = st_foreach(RHASH_ST_TABLE(hash), func, arg);
+        return st_foreach(RHASH_ST_TABLE(hash), func, arg);
     }
-    return (VALUE)ret;
 }
 
 int
-rb_hash_stlike_foreach(VALUE hash, st_foreach_callback_func *func, st_data_t arg)
+rb_hash_stlike_foreach_with_replace(VALUE hash, st_foreach_check_callback_func *func, st_update_callback_func *replace, st_data_t arg)
 {
-    struct hash_stlike_foreach_arg args = {
-        .hash = hash,
-        .func = func,
-        .arg = arg,
-    };
-    hash_iter_lev_inc(hash);
-    VALUE ret = rb_ensure(hash_stlike_foreach_call, (VALUE)&args,
-                          hash_foreach_ensure, hash);
-    return (int)ret;
-}
-
-struct hash_stlike_foreach_with_replace_arg {
-    VALUE hash;
-    st_foreach_check_callback_func *func;
-    st_update_callback_func *replace;
-    VALUE arg;
-};
-
-static VALUE
-hash_stlike_foreach_with_replace_call(VALUE args)
-{
-    struct hash_stlike_foreach_with_replace_arg *argp = (void *)args;
-    VALUE hash = argp->hash;
-    st_foreach_check_callback_func *func = argp->func;
-    st_update_callback_func *replace = argp->replace;
-    VALUE arg = argp->arg;
-    int ret;
-
     if (RHASH_AR_TABLE_P(hash)) {
-        ret = ar_foreach_with_replace(hash, func, replace, arg);
+        return ar_foreach_with_replace(hash, func, replace, arg);
     }
     else {
-        ret = st_foreach_with_replace(RHASH_ST_TABLE(hash), func, replace, arg);
+        return st_foreach_with_replace(RHASH_ST_TABLE(hash), func, replace, arg);
     }
-    return (VALUE)ret;
-}
-
-int
-rb_hash_stlike_foreach_with_replace(VALUE hash, st_foreach_check_callback_func *func,
-                                    st_update_callback_func *replace, st_data_t arg)
-{
-    struct hash_stlike_foreach_with_replace_arg args = {
-        .hash = hash,
-        .func = func,
-        .replace = replace,
-        .arg = arg,
-    };
-    hash_iter_lev_inc(hash);
-    VALUE ret = rb_ensure(hash_stlike_foreach_with_replace_call, (VALUE)&args,
-                          hash_foreach_ensure, hash);
-    return (int)ret;
 }
 
 static VALUE

test/ruby/test_hash.rb

@@ -1853,14 +1853,6 @@ def test_transform_values_bang
       end
     end
     assert_equal(@cls[a: 2, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7, h: 8, i: 9, j: 10], x)
-
-    x = (1..1337).to_h {|k| [k, k]}
-    assert_raise_with_message(RuntimeError, /rehash during iteration/) do
-      x.transform_values! {|v|
-        x.rehash if v == 1337
-        v * 2
-      }
-    end
   end
 
   def hrec h, n, &b