RFC: Static class

Zend/Optimizer/escape_analysis.c

@@ -162,7 +162,7 @@ static bool is_allocation_def(zend_op_array *op_array, zend_ssa *ssa, int def, i
 					script, op_array, opline);
 				uint32_t forbidden_flags =
 					/* These flags will always cause an exception */
-					ZEND_ACC_IMPLICIT_ABSTRACT_CLASS | ZEND_ACC_EXPLICIT_ABSTRACT_CLASS
+					ZEND_ACC_STATIC | ZEND_ACC_IMPLICIT_ABSTRACT_CLASS | ZEND_ACC_EXPLICIT_ABSTRACT_CLASS
 					| ZEND_ACC_INTERFACE | ZEND_ACC_TRAIT;
 				if (ce
 				 && !ce->parent

Zend/tests/readonly_classes/readonly_enum.phpt

@@ -9,4 +9,4 @@ readonly enum Foo
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "enum", expecting "abstract" or "final" or "readonly" or "class" in %s on line %d
+Parse error: syntax error, unexpected token "enum" in %s on line %d

Zend/tests/readonly_classes/readonly_interface.phpt

@@ -9,4 +9,4 @@ readonly interface Foo
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "interface", expecting "abstract" or "final" or "readonly" or "class" in %s on line %d
+Parse error: syntax error, unexpected token "interface" in %s on line %d

Zend/tests/readonly_classes/readonly_trait.phpt

@@ -9,4 +9,4 @@ readonly trait Foo
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "trait", expecting "abstract" or "final" or "readonly" or "class" in %s on line %d
+Parse error: syntax error, unexpected token "trait" in %s on line %d

Zend/tests/static_class/inherit_non-static_subclass.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Tests that a non-static class cannot inherit from a static class
+--FILE--
+<?php
+
+static class C {}
+
+class C2 extends C {}
+?>
+--EXPECTF--
+Fatal error: Non-static class C2 cannot extend static class C in %s on line %d

Zend/tests/static_class/inherit_non-static_superclass.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Tests that a static class cannot inherit from a non-static class
+--FILE--
+<?php
+
+class C {}
+
+static class C2 extends C {}
+?>
+--EXPECTF--
+Fatal error: Static class C2 cannot extend non-static class C in %s on line %d

Zend/tests/static_class/inherit_static_class.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Tests that a static class can inherit from another static class
+--FILE--
+<?php
+
+static class C {
+    static function F() {
+        echo 'OK';
+    }
+}
+
+static class C2 extends C {}
+
+C2::F();
+?>
+--EXPECT--
+OK

Zend/tests/static_class/inherit_trait.phpt

@@ -0,0 +1,21 @@
+--TEST--
+Tests that a static class can inherit static members from a trait
+--FILE--
+<?php
+
+trait T {
+    static $P = 'OK';
+
+    static function F() {
+        echo self::$P;
+    }
+}
+
+static class C {
+    use T;
+}
+
+C::F();
+?>
+--EXPECT--
+OK

Zend/tests/static_class/inherit_trait_instance_method.phpt

@@ -0,0 +1,15 @@
+--TEST--
+Tests that a static class cannot inherit an instance method from a trait
+--FILE--
+<?php
+
+trait T {
+    function F() {}
+}
+
+static class C {
+    use T;
+}
+?>
+--EXPECTF--
+Fatal error: Static class C cannot use trait with a non-static method T::F in %s on line %d

Zend/tests/static_class/inherit_trait_instance_property.phpt

@@ -0,0 +1,15 @@
+--TEST--
+Tests that a static class cannot inherit an instance property from a trait
+--FILE--
+<?php
+
+trait T {
+    var $V;
+}
+
+static class C {
+    use T;
+}
+?>
+--EXPECTF--
+Fatal error: Static class C cannot use trait with a non-static property T::$V in %s on line %d

Zend/tests/static_class/new_static_class.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Tests that a static class cannot be instantiated
+--FILE--
+<?php
+
+static class C {}
+
+new C;
+?>
+--EXPECTF--
+Fatal error: Uncaught Error: Cannot instantiate static class C in %s:%d
+Stack trace:%a

Zend/tests/static_class/new_static_class_via_reflection.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Tests that a static class cannot be instantiated via reflection
+--FILE--
+<?php
+
+static class C {}
+
+new ReflectionClass('C')->newInstance();
+?>
+--EXPECTF--
+Fatal error: Uncaught Error: Cannot instantiate static class C in %s:%d
+Stack trace:%a

Zend/tests/static_class/static_abstract_class.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Tests that a static class can be marked abstract
+--FILE--
+<?php
+
+abstract static class C {
+    abstract static function F();
+}
+
+static class C2 extends C {
+    static function F() {
+        echo 'OK';
+    }
+}
+
+C2::F();
+?>
+--EXPECT--
+OK

Zend/tests/static_class/static_anonymous_class.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Tests that an anonymous class cannot be marked static
+--FILE--
+<?php
+
+new static class C {}
+?>
+--EXPECTF--
+Fatal error: Cannot use the static modifier on an anonymous class in %s on line %d

Zend/tests/static_class/static_class.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Tests that a class can be marked static and functions as a static class
+--FILE--
+<?php
+
+static class C {
+    static $P = 'OK';
+
+    static function F() {
+        echo self::$P;
+    }
+}
+
+C::F();
+?>
+--EXPECT--
+OK

Zend/tests/static_class/static_class_ast_export.phpt

@@ -0,0 +1,13 @@
+--TEST--
+Tests that the AST export of a static class includes the static modifier
+--FILE--
+<?php
+
+assert(false && function () {
+    static class C {}
+});
+?>
+--EXPECTF--
+%a
+%wstatic class C {%w}
+%a

Zend/tests/static_class/static_class_call_static.phpt

@@ -0,0 +1,15 @@
+--TEST--
+Tests that a static class allows __callStatic() magic method
+--FILE--
+<?php
+
+static class C {
+    static function __callStatic(string $name, array $arguments) {
+        echo $name;
+    }
+}
+
+C::F();
+?>
+--EXPECT--
+F

Zend/tests/static_class/static_class_instance_method.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Tests that a static class cannot contain an instance method
+--FILE--
+<?php
+
+static class C {
+    function F() {}
+}
+?>
+--EXPECTF--
+Fatal error: Class method C::F() must be declared static in a static class in %s on line %d

Zend/tests/static_class/static_final_class.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Tests that a static class can be marked final
+--FILE--
+<?php
+
+final static class C {}
+
+static class C2 extends C {}
+?>
+--EXPECTF--
+Fatal error: Class C2 cannot extend final class C in %s on line %d

Zend/tests/static_class/static_interface.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Tests that an interface cannot be declared static
+--FILE--
+<?php
+
+static interface I {}
+?>
+--EXPECTF--
+Parse error: syntax error, unexpected token "interface" in %s on line %d

Zend/tests/static_class/static_readonly_class.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Tests that a static class cannot be marked readonly
+--FILE--
+<?php
+
+static readonly class C {}
+?>
+--EXPECTF--
+Fatal error: Cannot use the static modifier on a readonly class in %s on line %d

Zend/tests/static_class/static_static_class.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Tests that a static class cannot be so marked more than once
+--FILE--
+<?php
+
+static static class C {}
+?>
+--EXPECTF--
+Fatal error: Multiple static modifiers are not allowed in %s on line %d

Zend/tests/static_class/static_trait.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Tests that a trait cannot be declared static
+--FILE--
+<?php
+
+static trait T {}
+?>
+--EXPECTF--
+Parse error: syntax error, unexpected token "trait" in %s on line %d

Zend/tests/static_class/unserialize_static_class.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Tests that a static class cannot be created via unserialize()
+--FILE--
+<?php
+
+static class C {}
+
+unserialize('O:1:"C":0:{}');
+?>
+--EXPECTF--
+Fatal error: Uncaught Error: Cannot instantiate static class C in %s:%d
+Stack trace:%a

Zend/zend_API.c

@@ -1795,13 +1795,15 @@ ZEND_API void object_properties_load(zend_object *object, HashTable *properties)
  * calling zend_merge_properties(). */
 static zend_always_inline zend_result _object_and_properties_init(zval *arg, zend_class_entry *class_type, HashTable *properties) /* {{{ */
 {
-	if (UNEXPECTED(class_type->ce_flags & (ZEND_ACC_INTERFACE|ZEND_ACC_TRAIT|ZEND_ACC_IMPLICIT_ABSTRACT_CLASS|ZEND_ACC_EXPLICIT_ABSTRACT_CLASS|ZEND_ACC_ENUM))) {
+	if (UNEXPECTED(class_type->ce_flags & (ZEND_ACC_STATIC|ZEND_ACC_INTERFACE|ZEND_ACC_TRAIT|ZEND_ACC_IMPLICIT_ABSTRACT_CLASS|ZEND_ACC_EXPLICIT_ABSTRACT_CLASS|ZEND_ACC_ENUM))) {
 		if (class_type->ce_flags & ZEND_ACC_INTERFACE) {
 			zend_throw_error(NULL, "Cannot instantiate interface %s", ZSTR_VAL(class_type->name));
 		} else if (class_type->ce_flags & ZEND_ACC_TRAIT) {
 			zend_throw_error(NULL, "Cannot instantiate trait %s", ZSTR_VAL(class_type->name));
 		} else if (class_type->ce_flags & ZEND_ACC_ENUM) {
 			zend_throw_error(NULL, "Cannot instantiate enum %s", ZSTR_VAL(class_type->name));
+		} else if (class_type->ce_flags & ZEND_ACC_STATIC) {
+			zend_throw_error(NULL, "Cannot instantiate static class %s", ZSTR_VAL(class_type->name));
 		} else {
 			zend_throw_error(NULL, "Cannot instantiate abstract class %s", ZSTR_VAL(class_type->name));
 		}

Zend/zend_ast.c

@@ -1837,6 +1837,9 @@ static ZEND_COLD void zend_ast_export_ex(smart_str *str, zend_ast *ast, int prio
 				if (decl->flags & ZEND_ACC_EXPLICIT_ABSTRACT_CLASS) {
 					smart_str_appends(str, "abstract ");
 				}
+				if (decl->flags & ZEND_ACC_STATIC) {
+					smart_str_appends(str, "static ");
+				}
 				if (decl->flags & ZEND_ACC_FINAL) {
 					smart_str_appends(str, "final ");
 				}

Zend/zend_compile.c

@@ -944,6 +944,16 @@ uint32_t zend_add_class_modifier(uint32_t flags, uint32_t new_flag) /* {{{ */
 			"Cannot use the final modifier on an abstract class", 0);
 		return 0;
 	}
+	if ((new_flags & ZEND_ACC_STATIC) && (new_flags & ZEND_ACC_READONLY_CLASS)) {
+		zend_throw_exception(zend_ce_compile_error, "Cannot use the static modifier on a readonly class", 0);
+		return 0;
+	}
+    if ((flags & ZEND_ACC_STATIC) && (new_flag & ZEND_ACC_STATIC)) {
+		zend_throw_exception(zend_ce_compile_error,
+			"Multiple static modifiers are not allowed", 0);
+		return 0;
+	}
+
 	return new_flags;
 }
 /* }}} */
@@ -960,6 +970,10 @@ uint32_t zend_add_anonymous_class_modifier(uint32_t flags, uint32_t new_flag)
 		zend_throw_exception(zend_ce_compile_error, "Cannot use the final modifier on an anonymous class", 0);
 		return 0;
 	}
+	if (new_flag & ZEND_ACC_STATIC) {
+		zend_throw_exception(zend_ce_compile_error, "Cannot use the static modifier on an anonymous class", 0);
+		return 0;
+	}
 	if ((flags & ZEND_ACC_READONLY_CLASS) && (new_flag & ZEND_ACC_READONLY_CLASS)) {
 		zend_throw_exception(zend_ce_compile_error, "Multiple readonly modifiers are not allowed", 0);
 		return 0;
@@ -7838,6 +7852,11 @@ static zend_string *zend_begin_method_decl(zend_op_array *op_array, zend_string
 		zend_error(E_COMPILE_WARNING, "Private methods cannot be final as they are never overridden by other classes");
 	}
 
+	if ((ce->ce_flags & ZEND_ACC_STATIC) && !(fn_flags & ZEND_ACC_STATIC)) {
+		zend_error(E_COMPILE_ERROR, "Class method %s::%s() must be declared static in a static class",
+			ZSTR_VAL(ce->name), ZSTR_VAL(name));
+	}
+
 	if (in_interface) {
 		if (!(fn_flags & ZEND_ACC_PUBLIC)) {
 			zend_error_noreturn(E_COMPILE_ERROR, "Access type for interface method "

Zend/zend_compile.h

@@ -218,7 +218,7 @@ typedef struct _zend_oparray_context {
 #define ZEND_ACC_CHANGED                 (1 <<  3) /*     |  X  |  X  |     */
 /*                                                        |     |     |     */
 /* Static method or property                              |     |     |     */
-#define ZEND_ACC_STATIC                  (1 <<  4) /*     |  X  |  X  |     */
+#define ZEND_ACC_STATIC                  (1 <<  4) /*  X  |  X  |  X  |     */
 /*                                                        |     |     |     */
 /* Promoted property / parameter                          |     |     |     */
 #define ZEND_ACC_PROMOTED                (1 <<  5) /*     |     |  X  |  X  */
@@ -251,7 +251,7 @@ typedef struct _zend_oparray_context {
 /* or IS_CONSTANT_VISITED_MARK                            |     |     |     */
 #define ZEND_CLASS_CONST_IS_CASE         (1 << 6)  /*     |     |     |  X  */
 /*                                                        |     |     |     */
-/* Class Flags (unused: 30,31)                            |     |     |     */
+/* Class Flags (unused: 31)                               |     |     |     */
 /* ===========                                            |     |     |     */
 /*                                                        |     |     |     */
 /* Special class types                                    |     |     |     */
@@ -265,7 +265,7 @@ typedef struct _zend_oparray_context {
 /*                                                        |     |     |     */
 /* Class is abstract, since it is set by any              |     |     |     */
 /* abstract method                                        |     |     |     */
-#define ZEND_ACC_IMPLICIT_ABSTRACT_CLASS (1 <<  4) /*  X  |     |     |     */
+#define ZEND_ACC_IMPLICIT_ABSTRACT_CLASS (1 << 30) /*  X  |     |     |     */
 /*                                                        |     |     |     */
 /* Class has magic methods __get/__set/__unset/           |     |     |     */
 /* __isset that use guards                                |     |     |     */