Merge branch 'master' into dist/4.0/trixie

Author: sorah

ChangeLog

@@ -7070,7 +7070,7 @@ int_pow_tmp3(VALUE x, VALUE y, VALUE m, int nega_flg)
     zn = mn;
     z = bignew(zn, 1);
     bary_powm_gmp(BDIGITS(z), zn, BDIGITS(x), xn, BDIGITS(y), yn, BDIGITS(m), mn);
-    if (nega_flg & BIGNUM_POSITIVE_P(z)) {
+    if (nega_flg && BIGNUM_POSITIVE_P(z) && !BIGZEROP(z)) {
         z = rb_big_minus(z, m);
     }
     RB_GC_GUARD(x);
@@ -7098,7 +7098,7 @@ int_pow_tmp3(VALUE x, VALUE y, VALUE m, int nega_flg)
         x = rb_int_modulo(x, m);
     }
 
-    if (nega_flg && rb_int_positive_p(tmp)) {
+    if (nega_flg && rb_int_positive_p(tmp) && !rb_int_zero_p(tmp)) {
         tmp = rb_int_minus(tmp, m);
     }
     return tmp;
@@ -7210,6 +7210,11 @@ rb_int_powm(int const argc, VALUE * const argv, VALUE const num)
             rb_raise(rb_eTypeError, "Integer#pow() 2nd argument not allowed unless all arguments are integers");
         }
 
+        if (rb_int_zero_p(a) && !rb_int_zero_p(b)) {
+            /* shortcut; 0**x => 0 except for x == 0 */
+            return INT2FIX(0);
+        }
+
         if (rb_int_negative_p(m)) {
             m = rb_int_uminus(m);
             nega_flg = 1;

bignum.c

@@ -491,6 +491,7 @@ rb_class_duplicate_classext(rb_classext_t *orig, VALUE klass, const rb_box_t *bo
         while (subclass_entry) {
             if (subclass_entry->klass && RB_TYPE_P(subclass_entry->klass, T_ICLASS)) {
                 iclass = subclass_entry->klass;
+                VM_ASSERT(RB_TYPE_P(iclass, T_ICLASS));
                 if (RBASIC_CLASS(iclass) == klass) {
                     // Is the subclass an ICLASS including this module into another class
                     // If so we need to re-associate it under our box with the new ext
@@ -819,7 +820,8 @@ class_alloc0(enum ruby_value_type type, VALUE klass, bool boxable)
 static VALUE
 class_alloc(enum ruby_value_type type, VALUE klass)
 {
-    return class_alloc0(type, klass, false);
+    bool boxable = rb_box_available() && BOX_ROOT_P(rb_current_box());
+    return class_alloc0(type, klass, boxable);
 }
 
 static VALUE

class.c

@@ -1,3 +1,9 @@
+ruby4.0 (4.0.1-0nkmi1~dist) unstable; urgency=medium
+
+  * 4.0.1
+
+ -- Sorah Fukumori <her@sorah.jp>  Wed, 14 Jan 2026 08:59:19 +0900
+
 ruby4.0 (4.0.0-0nkmi1~dist) unstable; urgency=medium
 
   * Ruby 4.0!