revlog: make chainbase cache its result for the correct revision
Previously, as 'rev' was our iterator, we were always caching the chain base
for the second revision of the chain, or for the base itself.
#require test-repo pyflakes hg10
$ . "$TESTDIR/helpers-testrepo.sh"
run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)
$ cat > test.py <<EOF
> print(undefinedname)
> EOF
$ pyflakes test.py 2>/dev/null | "$TESTDIR/filterpyflakes.py"
test.py:1: undefined name 'undefinedname'
$ cd "`dirname "$TESTDIR"`"
$ testrepohg locate 'set:**.py or grep("^#!.*python")' \
> -X hgext/fsmonitor/pywatchman \
> -X mercurial/pycompat.py -X contrib/python-zstandard \
> -X mercurial/thirdparty/cbor \
> -X mercurial/thirdparty/concurrent \
> -X mercurial/thirdparty/zope \
> 2>/dev/null \
> | xargs pyflakes 2>/dev/null | "$TESTDIR/filterpyflakes.py"