branchmap: don't use buffer() on Python 3
This is certainly slower than the Python 2 code, but it works, and we
can revisit it later if it's a problem.
--- a/mercurial/branchmap.py Sun Mar 12 03:32:21 2017 -0400
+++ b/mercurial/branchmap.py Sun Mar 12 00:49:19 2017 -0500
@@ -409,7 +409,7 @@
# fast path: extract data from cache, use it if node is matching
reponode = changelog.node(rev)[:_rbcnodelen]
cachenode, branchidx = unpack(
- _rbcrecfmt, buffer(self._rbcrevs, rbcrevidx, _rbcrecsize))
+ _rbcrecfmt, util.buffer(self._rbcrevs, rbcrevidx, _rbcrecsize))
close = bool(branchidx & _rbccloseflag)
if close:
branchidx &= _rbcbranchidxmask