From 7e0ae8168917278fab2dc040f74aff220d6b8357 Mon Sep 17 00:00:00 2001
From: Jeremy Evans <code@jeremyevans.net>
Date: Mon, 23 Sep 2019 16:03:15 -0700
Subject: [PATCH] Support obj.clone(freeze: true) for freezing clone

This freezes the clone even if the receiver is not frozen.  It
is only for consistency with freeze: false not freezing the clone
even if the receiver is frozen.

Implements [Feature #16175]
---
 object.c                 | 41 +++++++++++++++++++++++-----------------
 test/ruby/test_object.rb |  8 ++++++++
 2 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/object.c b/object.c
index 9c603a8f10..fc43604526 100644
--- a/object.c
+++ b/object.c
@@ -351,9 +351,9 @@ init_copy(VALUE dest, VALUE obj)
     }
 }
 
-static int freeze_opt(int argc, VALUE *argv);
-static VALUE immutable_obj_clone(VALUE obj, int kwfreeze);
-static VALUE mutable_obj_clone(VALUE obj, int kwfreeze);
+static VALUE freeze_opt(int argc, VALUE *argv);
+static VALUE immutable_obj_clone(VALUE obj, VALUE kwfreeze);
+static VALUE mutable_obj_clone(VALUE obj, VALUE kwfreeze);
 PUREFUNC(static inline int special_object_p(VALUE obj)); /*!< \private */
 static inline int
 special_object_p(VALUE obj)
@@ -374,13 +374,13 @@ special_object_p(VALUE obj)
 
 /*
  *  call-seq:
- *     obj.clone(freeze: true) -> an_object
+ *     obj.clone(freeze: frozen?) -> an_object
  *
  *  Produces a shallow copy of <i>obj</i>---the instance variables of
  *  <i>obj</i> are copied, but not the objects they reference.
- *  #clone copies the frozen (unless +:freeze+ keyword argument is
- *  given with a false value) and tainted state of <i>obj</i>.  See
- *  also the discussion under Object#dup.
+ *  By default, #clone copies the frozen state of the object, but the
+ *  +:freeze+ keyword can override this. See also the discussion under
+ *  Object#dup.
  *
  *     class Klass
  *        attr_accessor :str
@@ -400,7 +400,7 @@ special_object_p(VALUE obj)
 static VALUE
 rb_obj_clone2(int argc, VALUE *argv, VALUE obj)
 {
-    int kwfreeze = freeze_opt(argc, argv);
+    VALUE kwfreeze = freeze_opt(argc, argv);
     if (!special_object_p(obj))
 	return mutable_obj_clone(obj, kwfreeze);
     return immutable_obj_clone(obj, kwfreeze);
@@ -410,16 +410,16 @@ rb_obj_clone2(int argc, VALUE *argv, VALUE obj)
 VALUE
 rb_immutable_obj_clone(int argc, VALUE *argv, VALUE obj)
 {
-    int kwfreeze = freeze_opt(argc, argv);
+    VALUE kwfreeze = freeze_opt(argc, argv);
     return immutable_obj_clone(obj, kwfreeze);
 }
 
-static int
+static VALUE
 freeze_opt(int argc, VALUE *argv)
 {
     static ID keyword_ids[1];
     VALUE opt;
-    VALUE kwfreeze;
+    VALUE kwfreeze = Qundef;
 
     if (!keyword_ids[0]) {
 	CONST_ID(keyword_ids[0], "freeze");
@@ -427,26 +427,26 @@ freeze_opt(int argc, VALUE *argv)
     rb_scan_args(argc, argv, "0:", &opt);
     if (!NIL_P(opt)) {
 	rb_get_kwargs(opt, keyword_ids, 0, 1, &kwfreeze);
-	if (kwfreeze == Qfalse) return FALSE;
+        if (kwfreeze == Qfalse) return kwfreeze;
 	if (kwfreeze != Qundef && kwfreeze != Qtrue) {
 	    rb_raise(rb_eArgError, "unexpected value for freeze: %"PRIsVALUE,
 		     rb_obj_class(kwfreeze));
 	}
     }
-    return TRUE;
+    return kwfreeze;
 }
 
 static VALUE
-immutable_obj_clone(VALUE obj, int kwfreeze)
+immutable_obj_clone(VALUE obj, VALUE kwfreeze)
 {
-    if (!kwfreeze)
+    if (kwfreeze == Qfalse)
 	rb_raise(rb_eArgError, "can't unfreeze %"PRIsVALUE,
 		 rb_obj_class(obj));
     return obj;
 }
 
 static VALUE
-mutable_obj_clone(VALUE obj, int kwfreeze)
+mutable_obj_clone(VALUE obj, VALUE kwfreeze)
 {
     VALUE clone, singleton;
 
@@ -461,8 +461,15 @@ mutable_obj_clone(VALUE obj, int kwfreeze)
     init_copy(clone, obj);
     rb_funcall(clone, id_init_clone, 1, obj);
 
-    if (kwfreeze) {
+    switch (kwfreeze) {
+      case Qtrue:
+        RBASIC(clone)->flags |= FL_FREEZE;
+        break;
+      case Qundef:
 	RBASIC(clone)->flags |= RBASIC(obj)->flags & FL_FREEZE;
+        break;
+      default:
+        break;
     }
 
     return clone;
diff --git a/test/ruby/test_object.rb b/test/ruby/test_object.rb
index fcb6c2826f..d14c9bc4ba 100644
--- a/test/ruby/test_object.rb
+++ b/test/ruby/test_object.rb
@@ -47,6 +47,14 @@ def test_clone
     a = Object.new
     def a.b; 2 end
 
+    c = a.clone
+    assert_equal(false, c.frozen?)
+    assert_equal(2, c.b)
+
+    c = a.clone(freeze: true)
+    assert_equal(true, c.frozen?)
+    assert_equal(2, c.b)
+
     a.freeze
     c = a.clone
     assert_equal(true, c.frozen?)
-- 
2.22.0