From df2db7fceaff4f46909f1aa8b31f0a9010631fc9 Mon Sep 17 00:00:00 2001
From: Nikita Popov <nikita.ppv@gmail.com>
Date: Mon, 8 Jun 2020 11:31:28 +0200
Subject: [PATCH] Fixed bug #79657

Throwing an exception should count as an initialization for this
purpose.
---
 NEWS                     |  2 ++
 Zend/tests/bug79657.phpt | 42 ++++++++++++++++++++++++++++++++++++++++
 Zend/zend_generators.c   |  1 +
 3 files changed, 45 insertions(+)
 create mode 100644 Zend/tests/bug79657.phpt

diff --git a/Zend/tests/bug79657.phpt b/Zend/tests/bug79657.phpt
new file mode 100644
index 000000000000..fb2ccab3e3ef
--- /dev/null
+++ b/Zend/tests/bug79657.phpt
@@ -0,0 +1,42 @@
+--TEST--
+Bug #79657: "yield from" hangs when invalid value encountered
+--FILE--
+<?php
+
+function throwException(): iterable
+{
+    throw new Exception();
+}
+
+function loop(): iterable
+{
+    $callbacks = [
+        function () {
+            yield 'first';
+        },
+        function () {
+            yield from throwException();
+        }
+    ];
+
+    foreach ($callbacks as $callback) {
+        yield from $callback();
+    }
+}
+
+function get(string $first, int $second): array
+{
+    return [];
+}
+
+get(...loop());
+
+?>
+--EXPECTF--
+Fatal error: Uncaught Exception in %s:%d
+Stack trace:
+#0 %s(%d): throwException()
+#1 %s(%d): {closure}()
+#2 %s(%d): loop()
+#3 {main}
+  thrown in %s on line %d
diff --git a/Zend/zend_generators.c b/Zend/zend_generators.c
index 4cd9087303a3..15bbfca1c58a 100644
--- a/Zend/zend_generators.c
+++ b/Zend/zend_generators.c
@@ -857,6 +857,7 @@ ZEND_API void zend_generator_resume(zend_generator *orig_generator) /* {{{ */
 			} else {
 				generator = zend_generator_get_current(orig_generator);
 				zend_generator_throw_exception(generator, NULL);
+				orig_generator->flags &= ~ZEND_GENERATOR_DO_INIT;
 				goto try_again;
 			}
 		}