bb.exceptions: don't choke on frames without arguments

(Bitbake rev: c9bb37e588ee7ee95eca798b0eae57bad68e8caf)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/exceptions.py

@@ -32,6 +32,9 @@ class TracebackEntry(namedtuple.abc):
 def _get_frame_args(frame):
     """Get the formatted arguments and class (if available) for a frame"""
     arginfo = inspect.getargvalues(frame)
+    if not arginfo.args:
+        return '', None
+
     firstarg = arginfo.args[0]
     if firstarg == 'self':
         self = arginfo.locals['self']