`Hash#dup` for kwsplat arguments

On `f(*a, **kw)` method calls, a rest keyword parameter is identically
same Hash object is passed and it should make `#dup`ed Hahs.

fix https://bugs.ruby-lang.org/issues/19526

1 files changed, 17 insertions, 3 deletions

diff --git a/vm_args.c b/vm_args.c
index 1af69cceee..cc7f1e29b5 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -450,6 +450,18 @@ ignore_keyword_hash_p(VALUE keyword_hash, const rb_iseq_t * const iseq, unsigned
            RHASH_EMPTY_P(keyword_hash);
 }
 
+static VALUE
+check_kwrestarg(VALUE keyword_hash, unsigned int *kw_flag)
+{
+    if (!(*kw_flag & VM_CALL_KW_SPLAT_MUT)) {
+        *kw_flag |= VM_CALL_KW_SPLAT_MUT;
+        return rb_hash_dup(keyword_hash);
+    }
+    else {
+        return keyword_hash;
+    }
+}
+
 static int
 setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * const iseq,
                          struct rb_calling_info *const calling,
@@ -528,12 +540,14 @@ setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * co
             keyword_hash = Qnil;
         }
         else if (UNLIKELY(ISEQ_BODY(iseq)->param.flags.ruby2_keywords)) {
-            flag_keyword_hash = keyword_hash;
-            rb_ary_push(args->rest, keyword_hash);
+            converted_keyword_hash = check_kwrestarg(converted_keyword_hash, &kw_flag);
+            flag_keyword_hash = converted_keyword_hash;
+            rb_ary_push(args->rest, converted_keyword_hash);
             keyword_hash = Qnil;
         }
         else if (!ISEQ_BODY(iseq)->param.flags.has_kwrest && !ISEQ_BODY(iseq)->param.flags.has_kw) {
-            rb_ary_push(args->rest, keyword_hash);
+            converted_keyword_hash = check_kwrestarg(converted_keyword_hash, &kw_flag);
+            rb_ary_push(args->rest, converted_keyword_hash);
             keyword_hash = Qnil;
         }