Issue #21883: os.path.join() and os.path.relpath() now raise a TypeError with
more helpful error message for unsupported or mismatched types of arguments.
diff --git a/Lib/genericpath.py b/Lib/genericpath.py
index ca4a510..6714061 100644
--- a/Lib/genericpath.py
+++ b/Lib/genericpath.py
@@ -130,3 +130,16 @@
filenameIndex += 1
return p, p[:0]
+
+def _check_arg_types(funcname, *args):
+ hasstr = hasbytes = False
+ for s in args:
+ if isinstance(s, str):
+ hasstr = True
+ elif isinstance(s, bytes):
+ hasbytes = True
+ else:
+ raise TypeError('%s() argument must be str or bytes, not %r' %
+ (funcname, s.__class__.__name__)) from None
+ if hasstr and hasbytes:
+ raise TypeError("Can't mix strings and bytes in path components") from None