Implement "Constructor Promotion"

php · nikic · Mar 24, 2020 · Apr 2, 2020 · Apr 2, 2020 · Apr 2, 2020
commit a7c7d9180edf664bf678df583bf69676e33ecd69
diff --git a/Zend/tests/ctor_promotion_abstract.phpt b/Zend/tests/ctor_promotion_abstract.phpt
@@ -0,0 +1,12 @@
+--TEST--
+Constructor promotion cannot be used inside an abstract constructor
+--FILE--
+<?php
+
+abstract class Test {
+    abstract public function __construct(public int $x);
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot declare promoted property in an abstract constructor in %s on line %d
diff --git a/Zend/tests/ctor_promotion_additional_modifiers.phpt b/Zend/tests/ctor_promotion_additional_modifiers.phpt
@@ -0,0 +1,12 @@
+--TEST--
+Constructor promotion only permits visibility modifiers
+--FILE--
+<?php
+
+class Test {
+    public function __construct(public static $x) {}
+}
+
+?>
+--EXPECTF--
+Parse error: syntax error, unexpected 'static' (T_STATIC), expecting variable (T_VARIABLE) in %s on line %d
diff --git a/Zend/tests/ctor_promotion_basic.phpt b/Zend/tests/ctor_promotion_basic.phpt
@@ -0,0 +1,21 @@
+--TEST--
+Constructor promotion (basic example)
+--FILE--
+<?php
+
+class Point {
+    public function __construct(public int $x, public int $y, public int $z) {}
+}
+
+$point = new Point(1, 2, 3);
+
+// Check that properties really are typed.
+try {
+    $point->x = "foo";
+} catch (TypeError $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECT--
+Cannot assign string to property Point::$x of type int
diff --git a/Zend/tests/ctor_promotion_by_ref.phpt b/Zend/tests/ctor_promotion_by_ref.phpt
@@ -0,0 +1,20 @@
+--TEST--
+Constructor promotion of by-ref parameter
+--FILE--
+<?php
+
+class Ary {
+    public function __construct(public array &$array) {}
+}
+
+$array = [];
+$ary = new Ary($array);
+$array[] = 42;
+var_dump($ary->array);
+
+?>
+--EXPECT--
+array(1) {
+  [0]=>
+  int(42)
+}
diff --git a/Zend/tests/ctor_promotion_callable_type.phpt b/Zend/tests/ctor_promotion_callable_type.phpt
@@ -0,0 +1,12 @@
+--TEST--
+Type of promoted property may not be callable
+--FILE--
+<?php
+
+class Test {
+    public function __construct(public callable $callable) {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Property Test::$callable cannot have type callable in %s on line %d
diff --git a/Zend/tests/ctor_promotion_defaults.phpt b/Zend/tests/ctor_promotion_defaults.phpt
@@ -0,0 +1,43 @@
+--TEST--
+Constructor promotion with default values
+--FILE--
+<?php
+
+class Point {
+    public function __construct(
+        public float $x = 0.0,
+        public float $y = 1.0,
+        public float $z = 2.0
+    ) {}
+}
+
+var_dump(new Point(10.0));
+var_dump(new Point(10.0, 11.0));
+var_dump(new Point(10.0, 11.0, 12.0));
+
+?>
+--EXPECT--
+object(Point)#1 (3) {
+  ["x"]=>
+  float(10)
+  ["y"]=>
+  float(1)
+  ["z"]=>
+  float(2)
+}
+object(Point)#1 (3) {
+  ["x"]=>
+  float(10)
+  ["y"]=>
+  float(11)
+  ["z"]=>
+  float(2)
+}
+object(Point)#1 (3) {
+  ["x"]=>
+  float(10)
+  ["y"]=>
+  float(11)
+  ["z"]=>
+  float(12)
+}
diff --git a/Zend/tests/ctor_promotion_free_function.phpt b/Zend/tests/ctor_promotion_free_function.phpt
@@ -0,0 +1,10 @@
+--TEST--
+Constructor promotion cannot be used in a free function
+--FILE--
+<?php
+
+function __construct(public $prop) {}
+
+?>
+--EXPECTF--
+Fatal error: Cannot declare promoted property outside a constructor in %s on line %d
diff --git a/Zend/tests/ctor_promotion_interface.phpt b/Zend/tests/ctor_promotion_interface.phpt
@@ -0,0 +1,12 @@
+--TEST--
+Constructor promotion cannot be used inside an abstract constructor (interface variant)
+--FILE--
+<?php
+
+interface Test {
+    public function __construct(public int $x);
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot declare promoted property in an abstract constructor in %s on line %d
diff --git a/Zend/tests/ctor_promotion_mixing.phpt b/Zend/tests/ctor_promotion_mixing.phpt
@@ -0,0 +1,54 @@
+--TEST--
+Constructor promotiong mixed with other properties, parameters and code
+--FILE--
+<?php
+
+class Test {
+    public string $prop2;
+
+    public function __construct(public string $prop1 = "", $param2 = "") {
+        $this->prop2 = $prop1 . $param2;
+    }
+}
+
+var_dump(new Test("Foo", "Bar"));
+echo "\n";
+echo new ReflectionClass(Test::class), "\n";
+
+?>
+--EXPECTF--
+object(Test)#1 (2) {
+  ["prop2"]=>
+  string(6) "FooBar"
+  ["prop1"]=>
+  string(3) "Foo"
+}
+
+Class [ <user> class Test ] {
+  @@ %s
+
+  - Constants [0] {
+  }
+
+  - Static properties [0] {
+  }
+
+  - Static methods [0] {
+  }
+
+  - Properties [2] {
+    Property [ <default> public $prop2 ]
+    Property [ <default> public $prop1 ]
+  }
+
+  - Methods [1] {
+    Method [ <user, ctor> public method __construct ] {
+      @@ %s
+
+      - Parameters [2] {
+        Parameter #0 [ <optional> string $prop1 = '' ]
+        Parameter #1 [ <optional> $param2 = '' ]
+      }
+    }
+  }
+}
diff --git a/Zend/tests/ctor_promotion_not_a_ctor.phpt b/Zend/tests/ctor_promotion_not_a_ctor.phpt
@@ -0,0 +1,12 @@
+--TEST--
+Constructor promotion can only be used in constructors ... duh
+--FILE--
+<?php
+
+class Test {
+    public function foobar(public int $x, public int $y) {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot declare promoted property outside a constructor in %s on line %d
diff --git a/Zend/tests/ctor_promotion_null_default.phpt b/Zend/tests/ctor_promotion_null_default.phpt
@@ -0,0 +1,12 @@
+--TEST--
+Constructor promotion with null default, requires an explicitly nullable type
+--FILE--
+<?php
+
+class Test {
+    public function __construct(public int $x = null) {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot use null as default value for parameter $x of type int in %s on line %d
diff --git a/Zend/tests/ctor_promotion_repeated_prop.phpt b/Zend/tests/ctor_promotion_repeated_prop.phpt
@@ -0,0 +1,14 @@
+--TEST--
+Clash between promoted and explicit property
+--FILE--
+<?php
+
+class Test {
+    public $prop;
+
+    public function __construct(public $prop) {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot redeclare Test::$prop in %s on line %d
diff --git a/Zend/tests/ctor_promotion_trait.phpt b/Zend/tests/ctor_promotion_trait.phpt
@@ -0,0 +1,21 @@
+--TEST--
+Constructor promotion can be used inside a trait
+--FILE--
+<?php
+
+trait Test {
+    public function __construct(public $prop) {}
+}
+
+class Test2 {
+    use Test;
+}
+
+var_dump(new Test2(42));
+
+?>
+--EXPECT--
+object(Test2)#1 (1) {
+  ["prop"]=>
+  int(42)
+}
diff --git a/Zend/tests/ctor_promotion_variadic.phpt b/Zend/tests/ctor_promotion_variadic.phpt
@@ -0,0 +1,12 @@
+--TEST--
+Cannot use constructor promotion with variadic parameter
+--FILE--
+<?php
+
+class Test {
+    public function __construct(public string ...$strings) {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot declare variadic promoted property in %s on line %d
diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
@@ -5790,6 +5790,8 @@ void zend_compile_params(zend_ast *ast, zend_ast *return_type_ast, uint32_t fall
 		zend_string *name = zval_make_interned_string(zend_ast_get_zval(var_ast));
 		zend_bool is_ref = (param_ast->attr & ZEND_PARAM_REF) != 0;
 		zend_bool is_variadic = (param_ast->attr & ZEND_PARAM_VARIADIC) != 0;
+		uint32_t visibility =
+			param_ast->attr & (ZEND_ACC_PUBLIC|ZEND_ACC_PROTECTED|ZEND_ACC_PRIVATE);
 
 		znode var_node, default_node;
 		zend_uchar opcode;
@@ -5862,16 +5864,16 @@ void zend_compile_params(zend_ast *ast, zend_ast *return_type_ast, uint32_t fall
 
 		if (type_ast) {
 			uint32_t default_type = default_ast ? Z_TYPE(default_node.u.constant) : IS_UNDEF;
+			zend_bool force_nullable = default_type == IS_NULL && !visibility;
 
 			op_array->fn_flags |= ZEND_ACC_HAS_TYPE_HINTS;
-			arg_info->type = zend_compile_typename(
-				type_ast, default_type == IS_NULL, /* use_arena */ 0);
+			arg_info->type = zend_compile_typename(type_ast, force_nullable, /* use_arena */ 0);
 
 			if (ZEND_TYPE_FULL_MASK(arg_info->type) & MAY_BE_VOID) {
 				zend_error_noreturn(E_COMPILE_ERROR, "void cannot be used as a parameter type");
 			}
 
-			if (default_type > IS_NULL && default_type != IS_CONSTANT_AST
+			if (default_type != IS_UNDEF && default_type != IS_CONSTANT_AST && !force_nullable
 					&& !zend_is_valid_default_value(arg_info->type, &default_node.u.constant)) {
 				zend_string *type_str = zend_type_to_string(arg_info->type);
 				zend_error_noreturn(E_COMPILE_ERROR,
@@ -5896,6 +5898,49 @@ void zend_compile_params(zend_ast *ast, zend_ast *return_type_ast, uint32_t fall
 			opline->op2.num = type_ast ?
 				ZEND_TYPE_FULL_MASK(arg_info->type) : MAY_BE_ANY;
 		}
+
+		if (visibility) {
+			zend_op_array *op_array = CG(active_op_array);
+			zend_class_entry *scope = op_array->scope;
+			zend_bool is_ctor =
+				scope && zend_string_equals_literal_ci(op_array->function_name, "__construct");
+			if (!is_ctor) {
+				zend_error_noreturn(E_COMPILE_ERROR,
+					"Cannot declare promoted property outside a constructor");
+			}
+			if ((op_array->fn_flags & ZEND_ACC_ABSTRACT)
+					|| (scope->ce_flags & ZEND_ACC_INTERFACE)) {
+				zend_error_noreturn(E_COMPILE_ERROR,
+					"Cannot declare promoted property in an abstract constructor");
+			}
+			if (is_variadic) {
+				zend_error_noreturn(E_COMPILE_ERROR,
+					"Cannot declare variadic promoted property");
+			}
+			if (zend_hash_exists(&scope->properties_info, name)) {
+				zend_error_noreturn(E_COMPILE_ERROR, "Cannot redeclare %s::$%s",
+					ZSTR_VAL(scope->name), ZSTR_VAL(name));
+			}
+			if (ZEND_TYPE_FULL_MASK(arg_info->type) & MAY_BE_CALLABLE) {
+				zend_string *str = zend_type_to_string(arg_info->type);
+				zend_error_noreturn(E_COMPILE_ERROR,
+					"Property %s::$%s cannot have type %s",
+					ZSTR_VAL(scope->name), ZSTR_VAL(name), ZSTR_VAL(str));
+			}
+
+			/* Always use uninitialized as the default. */
+			zval default_value;
+			ZVAL_UNDEF(&default_value);
+
+			/* Recompile the type, as it has different memory management requirements. */
+			zend_type type = ZEND_TYPE_INIT_NONE(0);
+			if (type_ast) {
+				type = zend_compile_typename(type_ast, /* force_allow_null */ 0, /* use_arena */ 1);
+			}
+
+			zend_declare_typed_property(
+				scope, name, &default_value, visibility, /* doc_comment */ NULL, type);
+		}
 	}
 
 	/* These are assigned at the end to avoid uninitialized memory in case of an error */
@@ -5907,6 +5952,29 @@ void zend_compile_params(zend_ast *ast, zend_ast *return_type_ast, uint32_t fall
 		op_array->num_args--;
 	}
 	zend_set_function_arg_flags((zend_function*)op_array);
+
+	for (i = 0; i < list->children; i++) {
+		zend_ast *param_ast = list->child[i];
+		zend_bool is_ref = (param_ast->attr & ZEND_PARAM_REF) != 0;
+		uint32_t visibility =
+			param_ast->attr & (ZEND_ACC_PUBLIC|ZEND_ACC_PROTECTED|ZEND_ACC_PRIVATE);
+		if (!visibility) {
+			continue;
+		}
+
+		/* Emit $this->prop = $prop for promoted properties. */
+		zend_string *name = zend_ast_get_str(param_ast->child[1]);
+		znode name_node, value_node;
+		name_node.op_type = IS_CONST;
+		ZVAL_STR_COPY(&name_node.u.constant, name);
+		value_node.op_type = IS_CV;
+		value_node.u.op.var = lookup_cv(name);
+
+		zend_op *opline = zend_emit_op(NULL,
+			is_ref ? ZEND_ASSIGN_OBJ_REF : ZEND_ASSIGN_OBJ, NULL, &name_node);
+		opline->extended_value = zend_alloc_cache_slots(3);
+		zend_emit_op_data(&value_node);
+	}
 }
 /* }}} */