This also affects a number of files under Lib, including some that set their version using "$Revision$".

Since I stumbled on this issue by encountering some code that checks the version string in tkinker breaking, this is an issue that can break existing code.

Mercurial does have the keyword extension (http://mercurial.selenic.com/wiki/KeywordExtension) which can provide something similar, but should be some sort of recommended configuration for this and there'll be discrepancies between the id's from svn and mercurial (which may or may not be an issue in practice).

find ./Lib -name "*.py" | xargs grep -n '"\$Revision\$"'

./Lib/tarfile.py:32:__version__ = "$Revision$"
./Lib/pydoc.py:45:__version__ = "$Revision$"
./Lib/tkinter/__init__.py:33:__version__ = "$Revision$"
./Lib/pickle.py:26:__version__ = "$Revision$"       # Code version