precheck: fix false warning about content-divergence creation
Before this patch, if we try to `hg prune` (without any successors) an
already obsoleted cset which has at least one successor, it would false
warn about new content-divergence. As we know, pruning cset without any
successors can not create any divergence.
Differential Revision: https://phab.mercurial-scm.org/D12002
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ hg commit -qAm x
$ echo y >> x
$ hg commit -qAm y
$ echo z >> x
$ hg commit -qAm z
$ echo a > a
$ hg commit -qAm a
$ cd ..
$ hgcloneshallow ssh://user@dummy/master shallow -q
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ cd shallow
Test blame
$ hg blame x
0: x
1: y
2: z
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
Test grepping the working directory.
$ hg grep --all-files x
x:x
$ echo foo >> x
$ hg grep --all-files x
x:x