Fix bug #65764

I'm not exactly sure whether this is the right way to fix it. The
question is whether Generator::throw() on a newborn generator (i.e.
a generator that is not yet at yield expression) should first advance to
the first yield and throw the exception there or whether it should
instead throw the exception in the caller's context.

The old behavior was to throw it at the start of the function (i.e.
the very first opcode), which causes issues like the one in #65764.
Effectively it's impossible to properly handle the exceptions in this
case.

For now I choose the variant where the generator advances to the
first yield before throwing, as that's consistent with how all other
methods on the Generator object currently behave. This does not
necessarily match the behavior in other languages, e.g. Python would throw
the exception in the caller's context. But then our send() method already
has this kind of deviation, so it stays internally consistent at least.

Author: nikic

NEWS

@@ -4,8 +4,10 @@ PHP                                                                        NEWS
 
 - Core:
   . Added validation of class names in the autoload process. (Dmitry)
-  . Fixed buf #66041 (list() fails to unpack yielded ArrayAccess object).
+  . Fixed bug #66041 (list() fails to unpack yielded ArrayAccess object).
     (Nikita)
+  . Fixed bug #65764 (generators/throw_rethrow FAIL with
+    ZEND_COMPILE_EXTENDED_INFO). (Nikita)
 
 - Date:
   . Fixed bug #66060 (Heap buffer over-read in DateInterval). (Remi)

Zend/tests/generators/throw_caught.phpt

@@ -4,6 +4,7 @@ Generator::throw() where the exception is caught in the generator
 <?php
 
 function gen() {
+    echo "before yield\n";
     try {
         yield;
     } catch (RuntimeException $e) {
@@ -18,6 +19,7 @@ var_dump($gen->throw(new RuntimeException('Test')));
 
 ?>
 --EXPECTF--
+before yield
 exception 'RuntimeException' with message 'Test' in %s:%d
 Stack trace:
 #0 {main}

Zend/tests/generators/throw_rethrow.phpt

@@ -4,6 +4,7 @@ Generator::throw() where the generator throws a different exception
 <?php
 
 function gen() {
+    echo "before yield\n";
     try {
         yield;
     } catch (RuntimeException $e) {
@@ -18,6 +19,7 @@ var_dump($gen->throw(new RuntimeException('throw')));
 
 ?>
 --EXPECTF--
+before yield
 Caught: exception 'RuntimeException' with message 'throw' in %s:%d
 Stack trace:
 #0 {main}

Zend/zend_generators.c

@@ -560,6 +560,8 @@ ZEND_METHOD(Generator, throw)
 
 	generator = (zend_generator *) zend_object_store_get_object(getThis() TSRMLS_CC);
 
+	zend_generator_ensure_initialized(generator TSRMLS_CC); 
+
 	if (generator->execute_data) {
 		/* Throw the exception in the context of the generator */
 		zend_execute_data *current_execute_data = EG(current_execute_data);