bpo-33034: Improve exception message when cast fails for {Parse,Split}Result.port (GH-6078)

Lib/urllib/parse.py

@@ -166,7 +166,11 @@ class _NetlocResultMixinBase(object):
     def port(self):
         port = self._hostinfo[1]
         if port is not None:
-            port = int(port, 10)
+            try:
+                port = int(port, 10)
+            except ValueError:
+                message = f'Port could not be cast to integer value as {port!r}'
+                raise ValueError(message) from None
             if not ( 0 <= port <= 65535):
                 raise ValueError("Port out of range 0-65535")
         return port