#6243: fix segfault when keyname() returns a NULL pointer.

Bug noted by Trundle, patched by Trundle and Jerry Chen.

Lib/test/test_curses.py

@@ -257,6 +257,10 @@ def test_resize_term(stdscr):
         if curses.LINES != lines - 1 or curses.COLS != cols + 1:
             raise RuntimeError, "Expected resizeterm to update LINES and COLS"
 
+def test_issue6243(stdscr):
+    curses.ungetch(1025)
+    stdscr.getkey()
+
 def main(stdscr):
     curses.savetty()
     try:
@@ -264,6 +268,7 @@ def main(stdscr):
         window_funcs(stdscr)
         test_userptr_without_set(stdscr)
         test_resize_term(stdscr)
+        test_issue6243(stdscr)
     finally:
         curses.resetty()
 

Modules/_cursesmodule.c

@@ -882,14 +882,17 @@ PyCursesWindow_GetKey(PyCursesWindowObject *self, PyObject *args)
     /* getch() returns ERR in nodelay mode */
     PyErr_SetString(PyCursesError, "no input");
     return NULL;
-  } else if (rtn<=255)
+  } else if (rtn<=255) {
     return Py_BuildValue("c", rtn);
-  else
+  } else {
+    const char *knp;
 #if defined(__NetBSD__)
-    return PyString_FromString(unctrl(rtn));
+    knp = unctrl(rtn);
 #else
-    return PyString_FromString((char *)keyname(rtn));
+    knp = keyname(rtn);
 #endif
+    return PyString_FromString((knp == NULL) ? "" : knp);
+  }
 }
 
 static PyObject *