Stop exposing `rb_str_chilled_p`

[Feature #20205]

Now that chilled strings no longer appear as frozen, there is no
need to offer an API to check for chilled strings.

We however need to change `rb_check_frozen_internal` to no
longer be a macro, as it needs to check for chilled strings.

error.c

@@ -3914,14 +3914,20 @@ rb_error_frozen_object(VALUE frozen_obj)
 void
 rb_check_frozen(VALUE obj)
 {
-    rb_check_frozen_internal(obj);
+    if (RB_UNLIKELY(RB_OBJ_FROZEN(obj))) {
+        rb_error_frozen_object(obj);
+    }
+
+    if (RB_UNLIKELY(CHILLED_STRING_P(obj))) {
+        rb_str_modify(obj);
+    }
 }
 
 void
 rb_check_copyable(VALUE obj, VALUE orig)
 {
     if (!FL_ABLE(obj)) return;
-    rb_check_frozen_internal(obj);
+    rb_check_frozen(obj);
     if (!FL_ABLE(orig)) return;
 }
 

ext/-test-/string/chilled.c

@@ -1,13 +0,0 @@
-#include "ruby.h"
-
-static VALUE
-bug_s_rb_str_chilled_p(VALUE self, VALUE str)
-{
-    return rb_str_chilled_p(str) ? Qtrue : Qfalse;
-}
-
-void
-Init_string_chilled(VALUE klass)
-{
-    rb_define_singleton_method(klass, "rb_str_chilled_p", bug_s_rb_str_chilled_p, 1);
-}

include/ruby/internal/intern/error.h

@@ -237,9 +237,6 @@ RBIMPL_ATTR_NORETURN()
  */
 void rb_error_arity(int argc, int min, int max);
 
-bool rb_str_chilled_p(VALUE str);
-void rb_str_modify(VALUE str);
-
 RBIMPL_SYMBOL_EXPORT_END()
 
 /**
@@ -247,30 +244,10 @@ RBIMPL_SYMBOL_EXPORT_END()
  *
  * Does anyone use this?  Remain not deleted for compatibility.
  */
-#define rb_check_frozen_internal(obj) do { \
-        VALUE frozen_obj = (obj); \
-        if (RB_UNLIKELY(RB_OBJ_FROZEN(frozen_obj))) { \
-            rb_error_frozen_object(frozen_obj); \
-        } \
-        if (RB_UNLIKELY(rb_str_chilled_p(frozen_obj))) { \
-            rb_str_modify(frozen_obj); \
-        } \
-    } while (0)
+#define rb_check_frozen_internal rb_check_frozen
 
 /** @alias{rb_check_frozen} */
-static inline void
-rb_check_frozen_inline(VALUE obj)
-{
-    if (rb_str_chilled_p(obj)) {
-        rb_str_modify(obj);
-    }
-    if (RB_UNLIKELY(RB_OBJ_FROZEN(obj))) {
-        rb_error_frozen_object(obj);
-    }
-}
-
-/** @alias{rb_check_frozen} */
-#define rb_check_frozen rb_check_frozen_inline
+#define rb_check_frozen_inline rb_check_frozen
 
 /**
  * Ensures that the  passed integer is in  the passed range.  When  you can use

include/ruby/internal/intern/string.h

@@ -601,21 +601,6 @@ VALUE rb_str_dup(VALUE str);
  */
 VALUE rb_str_resurrect(VALUE str);
 
-/**
- * Returns whether a string is chilled or not.
- *
- * This function is temporary and users must check for its presence using
- * #ifdef HAVE_RB_STR_CHILLED_P. If HAVE_RB_STR_CHILLED_P is not defined, then
- * strings can't be chilled.
- *
- * @param[in]  str  A string.
- * @retval     1    The string is chilled.
- * @retval     0    Otherwise.
- */
-bool rb_str_chilled_p(VALUE str);
-
-#define HAVE_RB_STR_CHILLED_P 1
-
 /**
  * Obtains a "temporary  lock" of the string.  This  advisory locking mechanism
  * prevents other  cooperating threads from  tampering the receiver.   The same

insns.def

@@ -222,7 +222,7 @@ setinstancevariable
 (ID id, IVC ic)
 (VALUE val)
 ()
-// attr bool leaf = false; /* has rb_check_frozen_internal() */
+// attr bool leaf = false; /* has rb_check_frozen() */
 {
     vm_setinstancevariable(GET_ISEQ(), GET_SELF(), id, val, ic);
 }

string.c

@@ -1898,12 +1898,6 @@ rb_ec_str_resurrect(struct rb_execution_context_struct *ec, VALUE str, bool chil
     return new_str;
 }
 
-bool
-rb_str_chilled_p(VALUE str)
-{
-    return CHILLED_STRING_P(str);
-}
-
 /*
  *
  *  call-seq:

test/-ext-/string/test_chilled.rb

@@ -1,19 +0,0 @@
-require 'test/unit'
-require '-test-/string'
-
-class Test_String_ChilledString < Test::Unit::TestCase
-  def test_rb_str_chilled_p
-    str = ""
-    assert_equal true, Bug::String.rb_str_chilled_p(str)
-  end
-
-  def test_rb_str_chilled_p_frozen
-    str = "".freeze
-    assert_equal false, Bug::String.rb_str_chilled_p(str)
-  end
-
-  def test_rb_str_chilled_p_mutable
-    str = "".dup
-    assert_equal false, Bug::String.rb_str_chilled_p(str)
-  end
-end

variable.c

@@ -1761,7 +1761,7 @@ rb_obj_ivar_set(VALUE obj, ID id, VALUE val)
 VALUE
 rb_vm_set_ivar_id(VALUE obj, ID id, VALUE val)
 {
-    rb_check_frozen_internal(obj);
+    rb_check_frozen(obj);
     rb_obj_ivar_set(obj, id, val);
     return val;
 }

vm_insnhelper.c

@@ -1419,7 +1419,7 @@ vm_setivar_slowpath(VALUE obj, ID id, VALUE val, const rb_iseq_t *iseq, IVC ic,
     RB_DEBUG_COUNTER_INC(ivar_set_ic_miss);
 
     if (BUILTIN_TYPE(obj) == T_OBJECT) {
-        rb_check_frozen_internal(obj);
+        rb_check_frozen(obj);
 
         attr_index_t index = rb_obj_ivar_set(obj, id, val);
 
@@ -3767,7 +3767,7 @@ vm_call_attrset_direct(rb_execution_context_t *ec, rb_control_frame_t *cfp, cons
     attr_index_t index = vm_cc_attr_index(cc);
     shape_id_t dest_shape_id = vm_cc_attr_index_dest_shape_id(cc);
     ID id = vm_cc_cme(cc)->def->body.attr.id;
-    rb_check_frozen_internal(obj);
+    rb_check_frozen(obj);
     VALUE res = vm_setivar(obj, id, val, dest_shape_id, index);
     if (UNDEF_P(res)) {
         switch (BUILTIN_TYPE(obj)) {