Version 35: Backward/forward emulation of list() format

Author: nikic

README.md

@@ -445,6 +445,10 @@ Version changelog
 * The `class` node of `AST_CATCH` is now always represented as an `AST_NAME_LIST`. In lower
   versions: On PHP 7.0 it will always be an `AST_NAME`. In PHP 7.1 it will be an `AST_NAME` if
   there is only a single class and `AST_NAME_LIST` otherwise.
+* `list()` destructuring is now always represented as an `AST_ARRAY` with `ARRAY_SYNTAX_LIST` flag.
+  In lower versions: On PHP 7.0 it will always be an `AST_LIST`. In PHP 7.1 it will be an
+  `AST_ARRAY` if `list()` is used with keys. In PHP 7.1 destructuring using `[]` will always be
+  represented using `AST_ARRAY`, independently of the version.
 
 ### 30 (current)
 

ast.c

@@ -233,6 +233,22 @@ static inline zend_ast_attr ast_assign_op_to_binary_op(zend_ast_attr attr) {
 	}
 }
 
+static inline zend_bool ast_array_is_list(zend_ast *ast) {
+	zend_ast_list *list = zend_ast_get_list(ast);
+	uint32_t i;
+	if (ast->attr != ZEND_ARRAY_SYNTAX_LIST) {
+		return 0;
+	}
+
+	for (i = 0; i < list->children; i++) {
+		if (list->child[i]->child[1] != NULL || list->child[i]->attr) {
+			return 0;
+		}
+	}
+
+	return 1;
+}
+
 static inline zend_ast **ast_get_children(zend_ast *ast, uint32_t *count) {
 	if (ast_kind_is_decl(ast->kind)) {
 		zend_ast_decl *decl = (zend_ast_decl *) ast;
@@ -378,6 +394,15 @@ static void ast_fill_children_ht(HashTable *ht, zend_ast *ast, zend_long version
 				&& (ast->kind == ZEND_AST_PROP_ELEM || ast->kind == ZEND_AST_CONST_ELEM)) {
 			/* Skip docComment child -- It's handled separately */
 			continue;
+#if PHP_VERSION_ID >= 70100
+		} else if (ast->kind == ZEND_AST_LIST) {
+			ast_to_zval(&child_zv, child->child[0], version);
+#else
+		} else if (ast->kind == ZEND_AST_LIST && version >= 35) {
+			zend_ast *new_child = zend_ast_create(ZEND_AST_ARRAY_ELEM, child, NULL);
+			new_child->lineno = zend_ast_get_lineno(child);
+			ast_to_zval(&child_zv, new_child, version);
+#endif
 		} else {
 			ast_to_zval(&child_zv, child, version);
 		}
@@ -447,6 +472,18 @@ static void ast_to_zval(zval *zv, zend_ast *ast, zend_long version) {
 		}
 	}
 
+#if PHP_VERSION_ID >= 70100
+	if (version < 35 && ast->kind == ZEND_AST_ARRAY && ast_array_is_list(ast)) {
+		ast->kind = ZEND_AST_LIST;
+		ast->attr = 0;
+	}
+#else
+	if (version >= 35 && ast->kind == ZEND_AST_LIST) {
+		ast->kind = ZEND_AST_ARRAY;
+		ast->attr = ZEND_AST_LIST;
+	}
+#endif
+
 	is_decl = ast_kind_is_decl(ast->kind);
 	object_init_ex(zv, is_decl ? ast_decl_ce : ast_node_ce);
 

tests/array_destructuring.phpt

@@ -9,7 +9,6 @@ require __DIR__ . '/../util.php';
 
 $code = <<<'PHP'
 <?php
-list($a, $b) = $x;
 list('foo' => $a, 'bar' => $b) = $x;
 [$a, $b] = $x;
 ['foo' => $a, 'bar' => $b] = $x;
@@ -22,21 +21,6 @@ echo ast_dump(ast\parse_code($code, $version=30));
 --EXPECT--
 AST_STMT_LIST
     0: AST_ASSIGN
-        var: AST_ARRAY
-            flags: ARRAY_SYNTAX_LIST (1)
-            0: AST_ARRAY_ELEM
-                flags: 0
-                value: AST_VAR
-                    name: "a"
-                key: null
-            1: AST_ARRAY_ELEM
-                flags: 0
-                value: AST_VAR
-                    name: "b"
-                key: null
-        expr: AST_VAR
-            name: "x"
-    1: AST_ASSIGN
         var: AST_ARRAY
             flags: ARRAY_SYNTAX_LIST (1)
             0: AST_ARRAY_ELEM
@@ -51,7 +35,7 @@ AST_STMT_LIST
                 key: "bar"
         expr: AST_VAR
             name: "x"
-    2: AST_ASSIGN
+    1: AST_ASSIGN
         var: AST_ARRAY
             flags: ARRAY_SYNTAX_SHORT (3)
             0: AST_ARRAY_ELEM
@@ -66,7 +50,7 @@ AST_STMT_LIST
                 key: null
         expr: AST_VAR
             name: "x"
-    3: AST_ASSIGN
+    2: AST_ASSIGN
         var: AST_ARRAY
             flags: ARRAY_SYNTAX_SHORT (3)
             0: AST_ARRAY_ELEM
@@ -81,7 +65,7 @@ AST_STMT_LIST
                 key: "bar"
         expr: AST_VAR
             name: "x"
-    4: AST_ASSIGN
+    3: AST_ASSIGN
         var: AST_ARRAY
             flags: ARRAY_SYNTAX_SHORT (3)
             0: null

tests/array_destructuring_old.phpt

@@ -0,0 +1,42 @@
+--TEST--
+Array destructuring (using unkeyed list())
+--FILE--
+<?php
+
+require __DIR__ . '/../util.php';
+
+$code = <<<'PHP'
+<?php
+list($a, $b) = $x;
+PHP;
+
+echo ast_dump(ast\parse_code($code, $version=30)), "\n";
+echo ast_dump(ast\parse_code($code, $version=35));
+
+?>
+--EXPECT--
+AST_STMT_LIST
+    0: AST_ASSIGN
+        var: AST_LIST
+            0: AST_VAR
+                name: "a"
+            1: AST_VAR
+                name: "b"
+        expr: AST_VAR
+            name: "x"
+AST_STMT_LIST
+    0: AST_ASSIGN
+        var: AST_ARRAY
+            flags: ARRAY_SYNTAX_LIST (1)
+            0: AST_ARRAY_ELEM
+                flags: 0
+                value: AST_VAR
+                    name: "a"
+                key: null
+            1: AST_ARRAY_ELEM
+                flags: 0
+                value: AST_VAR
+                    name: "b"
+                key: null
+        expr: AST_VAR
+            name: "x"