variable.c: Module#deprecate_constant

* variable.c (rb_const_get_0): warn deprecated constant reference.
* variable.c (rb_mod_deprecate_constant): mark constants to be
  warned as deprecated.  [Feature #11398]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51444 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,10 @@
+Thu Jul 30 13:19:54 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* variable.c (rb_const_get_0): warn deprecated constant reference.
+
+	* variable.c (rb_mod_deprecate_constant): mark constants to be
+	  warned as deprecated.  [Feature #11398]
+
 Thu Jul 30 11:53:54 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* thread.c (rb_thread_s_handle_interrupt): make identical hash,

NEWS

@@ -44,6 +44,9 @@ with all sufficient information, see the ChangeLog file.
     this parameter is bitwise-ORed to oflags generated by normal mode argument.
     [Feature #11253]
 
+* Module
+  * Module#deprecate_constant [Feature #11398]
+
 * NameError
   * NameError#receiver is added to take the receiver object. [Feature #10881]
 

constant.h

@@ -12,15 +12,21 @@
 #define CONSTANT_H
 
 typedef enum {
+    CONST_DEPRECATED = 0x100,
+
+    CONST_VISIBILITY_MASK = 0xff,
     CONST_PUBLIC    = 0x00,
     CONST_PRIVATE,
     CONST_VISIBILITY_MAX
 } rb_const_flag_t;
 
 #define RB_CONST_PRIVATE_P(ce) \
-    ((ce)->flag == CONST_PRIVATE)
+    (((ce)->flag & CONST_VISIBILITY_MASK) == CONST_PRIVATE)
 #define RB_CONST_PUBLIC_P(ce) \
-    ((ce)->flag == CONST_PUBLIC)
+    (((ce)->flag & CONST_VISIBILITY_MASK) == CONST_PUBLIC)
+
+#define RB_CONST_DEPRECATED_P(ce) \
+    ((ce)->flag & CONST_DEPRECATED)
 
 typedef struct rb_const_entry_struct {
     rb_const_flag_t flag;
@@ -31,6 +37,7 @@ typedef struct rb_const_entry_struct {
 
 VALUE rb_mod_private_constant(int argc, const VALUE *argv, VALUE obj);
 VALUE rb_mod_public_constant(int argc, const VALUE *argv, VALUE obj);
+VALUE rb_mod_deprecate_constant(int argc, const VALUE *argv, VALUE obj);
 void rb_free_const_table(st_table *tbl);
 VALUE rb_public_const_get(VALUE klass, ID id);
 VALUE rb_public_const_get_at(VALUE klass, ID id);

lib/timeout.rb

@@ -120,3 +120,6 @@ end
 # Another name for Timeout::Error, defined for backwards compatibility with
 # earlier versions of timeout.rb.
 TimeoutError = Timeout::Error
+class Object
+  deprecate_constant :TimeoutError
+end

object.c

@@ -3414,6 +3414,7 @@ Init_Object(void)
     rb_define_method(rb_cModule, "class_variable_defined?", rb_mod_cvar_defined, 1);
     rb_define_method(rb_cModule, "public_constant", rb_mod_public_constant, -1); /* in variable.c */
     rb_define_method(rb_cModule, "private_constant", rb_mod_private_constant, -1); /* in variable.c */
+    rb_define_method(rb_cModule, "deprecate_constant", rb_mod_deprecate_constant, -1); /* in variable.c */
     rb_define_method(rb_cModule, "singleton_class?", rb_mod_singleton_p, 0);
 
     rb_define_method(rb_cClass, "allocate", rb_obj_alloc, 0);

test/ruby/test_module.rb

@@ -1360,6 +1360,13 @@ class TestModule < Test::Unit::TestCase
     assert_equal("foo", c::FOO)
   end
 
+  def test_deprecate_constant
+    c = Class.new
+    c.const_set(:FOO, "foo")
+    c.deprecate_constant(:FOO)
+    assert_warn(/deprecated/) {c::FOO}
+  end
+
   def test_constants_with_private_constant
     assert_not_include(::TestModule.constants, :PrivateClass)
   end

variable.c

@@ -2149,6 +2149,15 @@ rb_const_get_0(VALUE klass, ID id, int exclude, int recurse, int visibility)
 		rb_name_error(id, "private constant %"PRIsVALUE"::%"PRIsVALUE" referenced",
 			      rb_class_name(klass), QUOTE_ID(id));
 	    }
+	    if (RB_CONST_DEPRECATED_P(ce)) {
+		if (klass == rb_cObject) {
+		    rb_warn("constant ::%"PRIsVALUE" is deprecated", QUOTE_ID(id));
+		}
+		else {
+		    rb_warn("constant %"PRIsVALUE"::%"PRIsVALUE" is deprecated",
+			    rb_class_name(klass), QUOTE_ID(id));
+		}
+	    }
 	    value = ce->value;
 	    if (value == Qundef) {
 		if (am == tmp) break;
@@ -2576,7 +2585,7 @@ rb_define_global_const(const char *name, VALUE val)
 }
 
 static void
-set_const_visibility(VALUE mod, int argc, const VALUE *argv, rb_const_flag_t flag)
+set_const_visibility(VALUE mod, int argc, const VALUE *argv, rb_const_flag_t flag, rb_const_flag_t mask)
 {
     int i;
     rb_const_entry_t *ce;
@@ -2600,7 +2609,8 @@ set_const_visibility(VALUE mod, int argc, const VALUE *argv, rb_const_flag_t fla
 			      rb_class_name(mod), QUOTE(val));
 	}
 	if ((ce = rb_const_lookup(mod, id))) {
-	    ce->flag = flag;
+	    ce->flag &= ~mask;
+	    ce->flag |= flag;
 	}
 	else {
 	    if (i > 0) {
@@ -2623,7 +2633,7 @@ set_const_visibility(VALUE mod, int argc, const VALUE *argv, rb_const_flag_t fla
 VALUE
 rb_mod_private_constant(int argc, const VALUE *argv, VALUE obj)
 {
-    set_const_visibility(obj, argc, argv, CONST_PRIVATE);
+    set_const_visibility(obj, argc, argv, CONST_PRIVATE, CONST_VISIBILITY_MASK);
     return obj;
 }
 
@@ -2637,7 +2647,14 @@ rb_mod_private_constant(int argc, const VALUE *argv, VALUE obj)
 VALUE
 rb_mod_public_constant(int argc, const VALUE *argv, VALUE obj)
 {
-    set_const_visibility(obj, argc, argv, CONST_PUBLIC);
+    set_const_visibility(obj, argc, argv, CONST_PUBLIC, CONST_VISIBILITY_MASK);
+    return obj;
+}
+
+VALUE
+rb_mod_deprecate_constant(int argc, const VALUE *argv, VALUE obj)
+{
+    set_const_visibility(obj, argc, argv, CONST_DEPRECATED, CONST_DEPRECATED);
     return obj;
 }