I don't have a specific use case. This spawned from a tangentially-related StackOverflow question (http://stackoverflow.com/questions/34858088), where in the answers a behavior difference between Python 2 and 3 was noted. I couldn't find any documentation to explain it, so I opened a follow-up question (http://stackoverflow.com/questions/34879318), and based on some feedback I got there, I opened up this issue.

Just to be sure I understand, you're suggesting deprecating truncate on text-mode file objects? And the interleaved read-writes are likely related to an issue that will be dealt with elsewhere?