symfony
diff --git a/‎src/Symfony/Component/Process/Process.php‎
Lines changed: 11 additions & 3 deletions b/‎src/Symfony/Component/Process/Process.php‎
Lines changed: 11 additions & 3 deletions
@@ -911,8 +911,16 @@ public function setTty($tty)
         if ('\\' === DIRECTORY_SEPARATOR && $tty) {
             throw new RuntimeException('TTY mode is not supported on Windows platform.');
         }
-        if ($tty && (!file_exists('/dev/tty') || !is_readable('/dev/tty'))) {
-            throw new RuntimeException('TTY mode requires /dev/tty to be readable.');
+        if ($tty) {
+            static $isTtySupported;
+
+            if (null === $isTtySupported) {
+                $isTtySupported = (bool) @proc_open('echo 1 >/dev/null', array(array('file', '/dev/tty', 'r'), array('file', '/dev/tty', 'w'), array('file', '/dev/tty', 'w')), $pipes);
+            }
+
+            if (!$isTtySupported) {
+                throw new RuntimeException('TTY mode requires /dev/tty to be read/writable.');
+            }
         }
 
         $this->tty = (bool) $tty;
@@ -1214,7 +1222,7 @@ public static function isPtySupported()
             return $result = false;
         }
 
-        return $result = (bool) @proc_open('echo 1', array(array('pty'), array('pty'), array('pty')), $pipes);
+        return $result = (bool) @proc_open('echo 1>/dev/null', array(array('pty'), array('pty'), array('pty')), $pipes);
     }
 
     /**
Original file line number	Diff line number	Diff line change
`@@ -911,8 +911,16 @@ public function setTty($tty)`
`911`	`911`	`if ('\\' === DIRECTORY_SEPARATOR && $tty) {`
`912`	`912`	`throw new RuntimeException('TTY mode is not supported on Windows platform.');`
`913`	`913`	`}`
`914`		`- if ($tty && (!file_exists('/dev/tty') \|\| !is_readable('/dev/tty'))) {`
`915`		`- throw new RuntimeException('TTY mode requires /dev/tty to be readable.');`
	`914`	`+ if ($tty) {`
	`915`	`+ static $isTtySupported;`
	`916`	`+`
	`917`	`+ if (null === $isTtySupported) {`
	`918`	`+ $isTtySupported = (bool) @proc_open('echo 1 >/dev/null', array(array('file', '/dev/tty', 'r'), array('file', '/dev/tty', 'w'), array('file', '/dev/tty', 'w')), $pipes);`
	`919`	`+ }`
	`920`	`+`
	`921`	`+ if (!$isTtySupported) {`
	`922`	`+ throw new RuntimeException('TTY mode requires /dev/tty to be read/writable.');`
	`923`	`+ }`
`916`	`924`	`}`
`917`	`925`
`918`	`926`	`$this->tty = (bool) $tty;`
`@@ -1214,7 +1222,7 @@ public static function isPtySupported()`
`1214`	`1222`	`return $result = false;`
`1215`	`1223`	`}`
`1216`	`1224`
`1217`		`- return $result = (bool) @proc_open('echo 1', array(array('pty'), array('pty'), array('pty')), $pipes);`
	`1225`	`+ return $result = (bool) @proc_open('echo 1>/dev/null', array(array('pty'), array('pty'), array('pty')), $pipes);`
`1218`	`1226`	`}`
`1219`	`1227`
`1220`	`1228`	`/**`