From 40f14bad33f428994b4a590dafa8fe4d058f7241 Mon Sep 17 00:00:00 2001
From: Thomas Punt <tpunt@hotmail.co.uk>
Date: Wed, 23 Mar 2016 23:57:50 +0000
Subject: [PATCH] Fix DateInterval::format segfault

---
 ext/date/php_date.c          |  4 ++++
 ext/date/tests/bug71889.phpt | 11 +++++++++++
 2 files changed, 15 insertions(+)
 create mode 100644 ext/date/tests/bug71889.phpt

diff --git a/ext/date/php_date.c b/ext/date/php_date.c
index 4cb0ec8ff4..4bb088881e 100644
--- a/ext/date/php_date.c
+++ b/ext/date/php_date.c
@@ -4359,6 +4359,10 @@ static char *date_interval_format(char *format, int format_len, timelib_rel_time
 
 	smart_str_0(&string);
 
+	if (string.c == NULL) {
+		return estrdup("");
+	}
+
 	return string.c;
 }
 /* }}} */
diff --git a/ext/date/tests/bug71889.phpt b/ext/date/tests/bug71889.phpt
new file mode 100644
index 0000000000..129930a1fc
--- /dev/null
+++ b/ext/date/tests/bug71889.phpt
@@ -0,0 +1,11 @@
+--TEST--
+Bug #71889 (DateInterval::format segfault on '%' input)
+--INI--
+date.timezone=US/Eastern
+--FILE--
+<?php
+$di = new DateInterval('P1D');
+var_dump($di->format("%"));
+?>
+--EXPECT--
+string(0) ""
-- 
2.40.0