branchcache: use an explicit class for the v2 version
This prepare the introduction of an experimental v3 format version.
In the process, we move the description of the format in that new class.
#require test-repo pure
$ . "$TESTDIR/helpers-testrepo.sh"
$ cd "$TESTDIR"/..
$ testrepohg files 'set:(**.py) - grep(pygments)' \
> -X hgext/fsmonitor/pywatchman \
> -X mercurial/cffi \
> -X mercurial/thirdparty \
> | sed 's|\\|/|g' | xargs "$PYTHON" contrib/check-py3-compat.py \
> | sed 's/[0-9][0-9]*)$/*)/'
hgext/convert/transport.py: error importing: <*Error> No module named 'svn.client' (error at transport.py:*) (glob) (?)
mercurial/scmwindows.py: error importing: <ValueError> _type_ 'v' not supported (error at win32.py:*) (no-windows !)
mercurial/win32.py: error importing: <ValueError> _type_ 'v' not supported (error at win32.py:*) (no-windows !)
mercurial/windows.py: error importing: <*Error> No module named 'msvcrt' (error at windows.py:*) (glob) (no-windows !)
mercurial/posix.py: error importing: <*Error> No module named 'fcntl' (error at posix.py:*) (glob) (windows !)
mercurial/scmposix.py: error importing: <*Error> No module named 'fcntl' (error at scmposix.py:*) (glob) (windows !)
#if pygments
$ testrepohg files 'set:(**.py) and grep(pygments)' | sed 's|\\|/|g' \
> | xargs "$PYTHON" contrib/check-py3-compat.py \
> | sed 's/[0-9][0-9]*)$/*)/'
#endif