[Python-Dev] when is binary mode required for pickle?

[Tim Peters]

Let me simplify this:  if you want a surprise-free and portable life, always
open pickle files in binary mode, regardless of pickling module (pickle or
cPickle), platform, pickle protocol, or whether reading or writing.

And, yes, the docs could be clearer about this.

The downside is that proto 0 (text mode) pickles "look funny" in Notepad on
Windows if written to a file opened in binary mode (they don't have the \r\n
line endings then that Notepad expects).