Zend: Warn when destructuring non-array values (#19439)

RFC: https://wiki.php.net/rfc/warnings-php-8-5#destructuring_non-array_values

Zend/tests/foreach/foreach_list_002.phpt

@@ -7,16 +7,48 @@ foreach (array(array(1,2), array(3,4)) as list($a, )) {
     var_dump($a);
 }
 
+echo "Array of strings:\n";
 $array = [['a', 'b'], 'c', 'd'];
 
 foreach($array as list(, $a)) {
    var_dump($a);
 }
 
+echo "Array of ints:\n";
+$array = [[5, 6], 10, 20];
+
+foreach($array as list(, $a)) {
+   var_dump($a);
+}
+
+echo "Array of nulls:\n";
+$array = [[null, null], null, null];
+
+foreach($array as list(, $a)) {
+   var_dump($a);
+}
+
 ?>
---EXPECT--
+--EXPECTF--
 int(1)
 int(3)
+Array of strings:
 string(1) "b"
+
+Warning: Cannot use string as array in %s on line %d
+NULL
+
+Warning: Cannot use string as array in %s on line %d
+NULL
+Array of ints:
+int(6)
+
+Warning: Cannot use int as array in %s on line %d
+NULL
+
+Warning: Cannot use int as array in %s on line %d
+NULL
+Array of nulls:
+NULL
 NULL
 NULL

Zend/tests/list/bug39304.phpt

@@ -8,5 +8,9 @@ Bug #39304 (Segmentation fault with list unpacking of string offset)
 ?>
 --EXPECTF--
 Warning: Uninitialized string offset 0 in %s on line %d
+
+Warning: Cannot use string as array in %s on line %d
+
+Warning: Cannot use string as array in %s on line %d
 NULL
 NULL

Zend/tests/list/destruct_bool.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Destructuring with list() a value of type bool
+--FILE--
+<?php
+
+$v = true;
+
+list($a, $b) = $v;
+
+var_dump($a, $b);
+
+?>
+--EXPECTF--
+Warning: Cannot use bool as array in %s on line %d
+
+Warning: Cannot use bool as array in %s on line %d
+NULL
+NULL

Zend/tests/list/destruct_float.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Destructuring with list() a value of type float
+--FILE--
+<?php
+
+$v = 25.64;
+
+list($a, $b) = $v;
+
+var_dump($a, $b);
+
+?>
+--EXPECTF--
+Warning: Cannot use float as array in %s on line %d
+
+Warning: Cannot use float as array in %s on line %d
+NULL
+NULL

Zend/tests/list/destruct_int.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Destructuring with list() a value of type int
+--FILE--
+<?php
+
+$v = 5;
+
+list($a, $b) = $v;
+
+var_dump($a, $b);
+
+?>
+--EXPECTF--
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+NULL
+NULL

Zend/tests/list/destruct_null.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Destructuring with list() a value of type null
+--FILE--
+<?php
+
+list($a) = null;
+
+var_dump($a);
+
+?>
+--EXPECT--
+NULL

Zend/tests/list/destruct_object_not_ArrayAccess.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Destructuring with list() a value of type object (that does not implement ArrayAccess)
+--FILE--
+<?php
+
+$v = new stdClass();
+
+list($a, $b) = $v;
+
+var_dump($a, $b);
+
+?>
+--EXPECTF--
+Fatal error: Uncaught Error: Cannot use object of type stdClass as array in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

Zend/tests/list/destruct_resource.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Destructuring with list() a value of type resource
+--FILE--
+<?php
+
+$v = STDERR;
+
+list($a, $b) = $v;
+
+var_dump($a, $b);
+
+?>
+--EXPECTF--
+Warning: Cannot use resource as array in %s on line %d
+
+Warning: Cannot use resource as array in %s on line %d
+NULL
+NULL

Zend/tests/list/destruct_string.phpt

@@ -0,0 +1,21 @@
+--TEST--
+Destructuring with list() a value of type string
+--FILE--
+<?php
+
+$v = 'hi';
+
+list($a, $b, $c) = $v;
+
+var_dump($a, $b, $c);
+
+?>
+--EXPECTF--
+Warning: Cannot use string as array in %s on line %d
+
+Warning: Cannot use string as array in %s on line %d
+
+Warning: Cannot use string as array in %s on line %d
+NULL
+NULL
+NULL

Zend/tests/list/list_003.phpt

@@ -1,24 +0,0 @@
---TEST--
-list() with non-array
---FILE--
-<?php
-
-list($a) = NULL;
-
-list($b) = 1;
-
-list($c) = 1.;
-
-list($d) = 'foo';
-
-list($e) = print '';
-
-var_dump($a, $b, $c, $d, $e);
-
-?>
---EXPECT--
-NULL
-NULL
-NULL
-NULL
-NULL

Zend/tests/list/list_005.phpt

@@ -1,50 +0,0 @@
---TEST--
-Testing list() with several variables
---FILE--
-<?php
-
-$str = "foo";
-
-list($a, $b, $c) = $str;
-
-var_dump($a, $b, $c);
-
-print "----\n";
-
-$int = 1;
-
-list($a, $b, $c) = $int;
-
-var_dump($a, $b, $c);
-
-print "----\n";
-
-$obj = new stdClass;
-
-list($a, $b, $c) = $obj;
-
-var_dump($a, $b, $c);
-
-print "----\n";
-
-$arr = array(1, 2, 3);
-
-list($a, $b, $c) = $arr;
-
-var_dump($a, $b, $c);
-
-?>
---EXPECTF--
-NULL
-NULL
-NULL
-----
-NULL
-NULL
-NULL
-----
-
-Fatal error: Uncaught Error: Cannot use object of type stdClass as array in %s:%d
-Stack trace:
-#0 {main}
-  thrown in %s on line %d

Zend/zend_execute.c

@@ -3005,7 +3005,7 @@ static zend_never_inline void ZEND_FASTCALL zend_fetch_dimension_address_UNSET(z
 	zend_fetch_dimension_address(result, container_ptr, dim, dim_type, BP_VAR_UNSET EXECUTE_DATA_CC);
 }
 
-static zend_always_inline void zend_fetch_dimension_address_read(zval *result, zval *container, zval *dim, int dim_type, int type, bool is_list, int slow EXECUTE_DATA_DC)
+static zend_always_inline void zend_fetch_dimension_address_read(zval *result, zval *container, zval *dim, int dim_type, int type, bool is_list, bool slow EXECUTE_DATA_DC)
 {
 	zval *retval;
 
@@ -3143,6 +3143,9 @@ try_string_offset:
 		if (ZEND_CONST_COND(dim_type == IS_CV, 1) && UNEXPECTED(Z_TYPE_P(dim) == IS_UNDEF)) {
 			ZVAL_UNDEFINED_OP2();
 		}
+		if (is_list && Z_TYPE_P(container) > IS_NULL) {
+			zend_error(E_WARNING, "Cannot use %s as array", zend_zval_type_name(container));
+		}
 		if (!is_list && type != BP_VAR_IS) {
 			zend_error(E_WARNING, "Trying to access array offset on %s",
 				zend_zval_value_name(container));

ext/opcache/jit/zend_jit_helpers.c

@@ -16,6 +16,7 @@
    +----------------------------------------------------------------------+
 */
 
+#include "Zend/zend_types.h"
 #include "Zend/zend_API.h"
 
 static ZEND_COLD void undef_result_after_exception(void) {
@@ -2561,6 +2562,14 @@ static void ZEND_FASTCALL zend_jit_only_vars_by_reference(zval *arg)
 	zend_error(E_NOTICE, "Only variables should be passed by reference");
 }
 
+static void ZEND_FASTCALL zend_jit_invalid_array_use(const zval *container)
+{
+	/* Warning should not occur on null */
+	if (Z_TYPE_P(container) != IS_NULL) {
+		zend_error(E_WARNING, "Cannot use %s as array", zend_zval_type_name(container));
+	}
+}
+
 static void ZEND_FASTCALL zend_jit_invalid_array_access(zval *container)
 {
 	zend_error(E_WARNING, "Trying to access array offset on %s", zend_zval_value_name(container));

ext/opcache/jit/zend_jit_ir.c

@@ -16,6 +16,7 @@
  *  +----------------------------------------------------------------------+
  */
 
+#include "Zend/zend_type_info.h"
 #include "jit/ir/ir.h"
 #include "jit/ir/ir_builder.h"
 #include "jit/tls/zend_jit_tls.h"
@@ -12786,7 +12787,7 @@ static int zend_jit_fetch_dim_read(zend_jit_ctx       *jit,
 				}
 			}
 
-			if (opline->opcode != ZEND_FETCH_DIM_IS && opline->opcode != ZEND_FETCH_LIST_R) {
+			if (opline->opcode != ZEND_FETCH_DIM_IS) {
 				ir_ref ref;
 
 				may_throw = 1;
@@ -12796,7 +12797,11 @@ static int zend_jit_fetch_dim_read(zend_jit_ctx       *jit,
 					jit_SET_EX_OPLINE(jit, opline);
 					ref = jit_ZVAL_ADDR(jit, op1_addr);
 				}
-				ir_CALL_1(IR_VOID, ir_CONST_FC_FUNC(zend_jit_invalid_array_access), ref);
+				if (opline->opcode == ZEND_FETCH_LIST_R) {
+					ir_CALL_1(IR_VOID, ir_CONST_FC_FUNC(zend_jit_invalid_array_use), ref);
+				} else {
+					ir_CALL_1(IR_VOID, ir_CONST_FC_FUNC(zend_jit_invalid_array_access), ref);
+				}
 			}
 
 			jit_set_Z_TYPE_INFO(jit, res_addr, IS_NULL);

ext/opcache/tests/jit/fetch_list_r_001.phpt

@@ -13,5 +13,6 @@ function test() {
 }
 test();
 ?>
---EXPECT--
+--EXPECTF--
+Warning: Cannot use string as array in %s on line %d
 NULL

ext/opcache/tests/opt/block_pass_003.phpt

@@ -1,5 +1,5 @@
 --TEST--
-Block Pass 003: Inorrect constant substitution in FETCH_LIST_R
+Block Pass 003: Incorrect constant substitution in FETCH_LIST_R
 --INI--
 opcache.enable=1
 opcache.enable_cli=1
@@ -16,5 +16,44 @@ function test() {
 test();
 ?>
 DONE
---EXPECT--
+--EXPECTF--
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
 DONE

tests/lang/engine_assignExecutionOrder_002.phpt

@@ -116,6 +116,10 @@ array(3) {
   int(3000)
 }
 L=100 M=200 N=300
+
+Warning: Cannot use int as array in %s on line %d
+
+Warning: Cannot use int as array in %s on line %d
 O= and P=
 10 20 40 50 60 70 80