input: Ignore touch up events if num_tp is 0
This can happen if we start out with one or more fingers on the touch
screen, in which case we didn't get the corresponding down event.
Closes: https://bugs.freedesktop.org/show_bug.cgi?id=73367
diff --git a/src/input.c b/src/input.c
index 902cfb8..157066c 100644
--- a/src/input.c
+++ b/src/input.c
@@ -1488,6 +1488,14 @@
grab->interface->motion(grab, time, touch_id, sx, sy);
break;
case WL_TOUCH_UP:
+ if (touch->num_tp == 0) {
+ /* This can happen if we start out with one or
+ * more fingers on the touch screen, in which
+ * case we didn't get the corresponding down
+ * event. */
+ weston_log("unmatched touch up event\n");
+ break;
+ }
weston_compositor_idle_release(ec);
touch->num_tp--;