warn() has a flag to print exception stack traces now

main.py

@@ -10,8 +10,11 @@ import sys, os, json, traceback
 EXIT_SUCCESS=0
 EXIT_ERROR=1
 
-def warn(message):
+def warn(message, is_exception=False):
     print("WARNING: "+str(message), file=sys.stderr)
+    if is_exception:
+        traceback.print_exc()
+    else:
         traceback.print_stack()
 
 def error(message, is_exception=True, handle_gracefully=True):