Add support for deprecating class constants

Author: Girgias

Zend/Optimizer/pass1.c

@@ -164,7 +164,7 @@ void zend_optimizer_pass1(zend_op_array *op_array, zend_optimizer_ctx *ctx)
 				if (ce) {
 					zend_class_constant *cc = zend_hash_find_ptr(
 						&ce->constants_table, Z_STR(ZEND_OP2_LITERAL(opline)));
-					if (cc && (ZEND_CLASS_CONST_FLAGS(cc) & ZEND_ACC_PPP_MASK) == ZEND_ACC_PUBLIC && !(ce->ce_flags & ZEND_ACC_TRAIT)) {
+					if (cc && !(ZEND_CLASS_CONST_FLAGS(cc) & ZEND_ACC_DEPRECATED) && (ZEND_CLASS_CONST_FLAGS(cc) & ZEND_ACC_PPP_MASK) == ZEND_ACC_PUBLIC && !(ce->ce_flags & ZEND_ACC_TRAIT)) {
 						zval *c = &cc->value;
 						if (Z_TYPE_P(c) == IS_CONSTANT_AST) {
 							zend_ast *ast = Z_ASTVAL_P(c);

Zend/zend_compile.c

@@ -1728,7 +1728,9 @@ static bool zend_try_compile_const_expr_resolve_class_name(zval *zv, zend_ast *c
 /* We don't use zend_verify_const_access because we need to deal with unlinked classes. */
 static bool zend_verify_ct_const_access(zend_class_constant *c, zend_class_entry *scope)
 {
-	if (c->ce->ce_flags & ZEND_ACC_TRAIT) {
+	if (ZEND_CLASS_CONST_FLAGS(c) & ZEND_ACC_DEPRECATED) {
+		return 0;
+	} else if (c->ce->ce_flags & ZEND_ACC_TRAIT) {
 		/* This condition is only met on directly accessing trait constants,
 		 * because the ce is replaced to the class entry of the composing class
 		 * on binding. */

Zend/zend_constants.c

@@ -347,6 +347,14 @@ ZEND_API zval *zend_get_class_constant_ex(zend_string *class_name, zend_string *
 				goto failure;
 			}
 
+			if (UNEXPECTED(ZEND_CLASS_CONST_FLAGS(c) & ZEND_ACC_DEPRECATED)) {
+				if ((flags & ZEND_FETCH_CLASS_SILENT) == 0) {
+					zend_error(E_DEPRECATED, "Constant %s::%s is deprecated", ZSTR_VAL(class_name), ZSTR_VAL(constant_name));
+					if (EG(exception)) {
+						goto failure;
+					}
+				}
+			}
 			ret_constant = &c->value;
 		}
 	}

Zend/zend_vm_def.h

@@ -5983,6 +5983,17 @@ ZEND_VM_HANDLER(181, ZEND_FETCH_CLASS_CONSTANT, VAR|CONST|UNUSED|CLASS_FETCH, CO
 				HANDLE_EXCEPTION();
 			}
 
+			bool is_constant_deprecated = ZEND_CLASS_CONST_FLAGS(c) & ZEND_ACC_DEPRECATED;
+			if (UNEXPECTED(is_constant_deprecated)) {
+				zend_error(E_DEPRECATED, "Constant %s::%s is deprecated", ZSTR_VAL(ce->name), ZSTR_VAL(constant_name));
+
+				if (EG(exception)) {
+					ZVAL_UNDEF(EX_VAR(opline->result.var));
+					FREE_OP2();
+					HANDLE_EXCEPTION();
+				}
+			}
+
 			value = &c->value;
 			// Enums require loading of all class constants to build the backed enum table
 			if (ce->ce_flags & ZEND_ACC_ENUM && ce->enum_backing_type != IS_UNDEF && ce->type == ZEND_USER_CLASS && !(ce->ce_flags & ZEND_ACC_CONSTANTS_UPDATED)) {
@@ -5999,7 +6010,7 @@ ZEND_VM_HANDLER(181, ZEND_FETCH_CLASS_CONSTANT, VAR|CONST|UNUSED|CLASS_FETCH, CO
 					HANDLE_EXCEPTION();
 				}
 			}
-			if (OP2_TYPE == IS_CONST) {
+			if (OP2_TYPE == IS_CONST && !is_constant_deprecated) {
 				CACHE_POLYMORPHIC_PTR(opline->extended_value, ce, value);
 			}
 		} else {