stream: in v3, skip the "size" fast path if the entries as some unknown size
We are about to prefetch size during the lock less in the v3 case. So we need to
avoid trying to use that prefetched size when it is not available.
See next changeset for the motivation.
$ hg init repo
$ cd repo
$ echo 0 > a
$ hg ci -qAm 0
$ for i in 5 8 14 43 167; do
> hg up -q 0
> echo $i > a
> hg ci -qm $i
> done
$ cat <<EOF >> .hg/hgrc
> [alias]
> l = log -T '{rev}:{shortest(node,1)}\n'
> EOF
$ hg l
5:00f
4:7ba5d
3:7ba57
2:72
1:9
0:b
$ cat <<EOF >> .hg/hgrc
> [experimental]
> revisions.disambiguatewithin=not 4
> EOF
$ hg l
5:00
4:7ba5d
3:7b
2:72
1:9
0:b
9 was unambiguous and still is
$ hg l -r 9
1:9
7 was ambiguous and still is
$ hg l -r 7
abort: ambiguous revision identifier: 7
[10]
7b is no longer ambiguous
$ hg l -r 7b
3:7b
$ cd ..