mercurial/utils/hashutil.py

rust-revlog: bare minimal NodeTree exposition

The independent `NodeTree` instances needs to be associated to an
index (for forward-checks of candidates) but do not need to
encompass all revisions from that index.

This is exactly how it is used in `scmutil.shortesthenodeidprefix`
and we restrict the implementation to the bare minimum needed there
and to write convincing tests.
It would of course be fairly trivial to add more.

import hashlib

try:
    from ..thirdparty import sha1dc  # pytype: disable=import-error

    sha1 = sha1dc.sha1
except (ImportError, AttributeError):
    sha1 = hashlib.sha1