fix unintentional bc break with compact('this') behavior

Author: marcioAlmada

ext/standard/array.c

@@ -1976,6 +1976,14 @@ static void php_compact_var(HashTable *eg_active_symbol_table, zval *return_valu
 			ZVAL_COPY(&data, value_ptr);
 			zend_hash_update(Z_ARRVAL_P(return_value), Z_STR_P(entry), &data);
 		}
+		if (zend_string_equals_literal(Z_STR_P(entry), "this")) {
+			zend_object *object = zend_get_this_object(EG(current_execute_data));
+			if (object) {
+				GC_REFCOUNT(object)++;
+				ZVAL_OBJ(&data, object);
+				zend_hash_update(Z_ARRVAL_P(return_value), Z_STR_P(entry), &data);
+			}
+		}
 	} else if (Z_TYPE_P(entry) == IS_ARRAY) {
 		if ((Z_ARRVAL_P(entry)->u.v.nApplyCount > 1)) {
 			php_error_docref(NULL, E_WARNING, "recursion detected");

ext/standard/tests/array/compact_no_this.phpt

@@ -0,0 +1,25 @@
+--TEST--
+compact() without object context
+--FILE--
+<?php
+
+var_dump(
+    (new class {
+        function test(){
+            return (static function(){ return compact('this'); })();
+        }
+    })->test()
+);
+
+var_dump(compact('this'));
+
+var_dump((function(){ return compact('this'); })());
+
+?>
+--EXPECT--
+array(0) {
+}
+array(0) {
+}
+array(0) {
+}

ext/standard/tests/array/compact_this.phpt

@@ -0,0 +1,46 @@
+--TEST--
+compact() with object context
+--FILE--
+<?php
+
+var_dump(
+    (new class {
+        function test(){
+            return compact('this');
+        }
+    })->test()
+);
+
+var_dump(
+    (new class {
+        function test(){
+            return compact([['this']]);
+        }
+    })->test()
+);
+
+var_dump(
+    (new class {
+        function test(){
+            return (function(){ return compact('this'); })();
+        }
+    })->test()
+);
+
+?>
+--EXPECT--
+array(1) {
+  ["this"]=>
+  object(class@anonymous)#1 (0) {
+  }
+}
+array(1) {
+  ["this"]=>
+  object(class@anonymous)#1 (0) {
+  }
+}
+array(1) {
+  ["this"]=>
+  object(class@anonymous)#1 (0) {
+  }
+}