Merge branch 'PHP-7.4'

* PHP-7.4:
  Fixed bug #78689

Author: nikic

Zend/tests/bug78689.phpt

@@ -0,0 +1,13 @@
+--TEST--
+Bug #78689: Closure::fromCallable() doesn't handle [Closure, '__invoke']
+--FILE--
+<?php
+$a = [function () { echo "123\n"; }, '__invoke'];
+$a();
+
+$b = Closure::fromCallable($a);
+$b();
+?>
+--EXPECT--
+123
+123

Zend/zend_closures.c

@@ -280,7 +280,13 @@ static int zend_create_closure_from_callable(zval *return_value, zval *callable,
 
 	mptr = fcc.function_handler;
 	if (mptr->common.fn_flags & ZEND_ACC_CALL_VIA_TRAMPOLINE) {
-		memset(&call, 0, sizeof(zend_internal_function));
+		/* For Closure::fromCallable([$closure, "__invoke"]) return $closure. */
+		if (fcc.object && fcc.object->ce == zend_ce_closure
+				&& zend_string_equals_literal(mptr->common.function_name, "__invoke")) {
+			ZVAL_OBJ(return_value, fcc.object);
+			zend_free_trampoline(mptr);
+			return SUCCESS;
+		}
 
 		if (!mptr->common.scope) {
 			return FAILURE;
@@ -295,6 +301,7 @@ static int zend_create_closure_from_callable(zval *return_value, zval *callable,
 			}
 		}
 
+		memset(&call, 0, sizeof(zend_internal_function));
 		call.type = ZEND_INTERNAL_FUNCTION;
 		call.fn_flags = mptr->common.fn_flags & ZEND_ACC_STATIC;
 		call.handler = zend_closure_call_magic;