You should read TFA.

I did. It basically said to change your input stream to avoid the problem. Not all data sources can be changed. If you don't have canonically parsable inputs, then assumptions don't work and you can't predict if an add::d:ress is with or without the :port syntax, a priori unless you know the input stream.

So between your input and your parsing library you should put a bit of code to clean up the incoming data. Don’t create a library that processes incorrect data because at some point someone will absolutely try to use it to parse different input data and it will cause problems.