Check that evolve shows error while handling split commits

--------------------------------------

  $ cat >> $HGRCPATH <<EOF

  > [defaults]

  > amend=-d "0 0"

  > fold=-d "0 0"

  > [web]

  > push_ssl = false

  > allow_push = *

  > [phases]

  > publish = False

  > [diff]

  > git = 1

  > unified = 0

  > [ui]

  > logtemplate = {rev}:{node|short}@{branch}({phase}) {desc|firstline}\n

  > [extensions]

  > EOF

  $ echo "evolve=$(echo $(dirname $TESTDIR))/hgext3rd/evolve/" >> $HGRCPATH

  $ mkcommit() {

  >    echo "$1" > "$1"

  >    hg add "$1"

  >    hg ci -m "add $1"

  > }

  $ hg init split

  $ cd split

  $ mkcommit aa

Create a split commit

  $ printf "oo" > oo;

  $ printf "pp" > pp;

  $ hg add oo pp

  $ hg commit -m "oo+pp"

  $ mkcommit uu

  $ hg up 0

  0 files updated, 0 files merged, 3 files removed, 0 files unresolved

  $ printf "oo" > oo;

  $ hg add oo

  $ hg commit -m "_oo"

  created new head

  $ printf "pp" > pp;

  $ hg add pp

  $ hg commit -m "_pp"

  $ hg prune --succ "desc(_oo) + desc(_pp)" -r "desc('oo+pp')" --split

  1 changesets pruned

  1 new unstable changesets

  $ hg log -G

  @  4:d0dcf24cddd3@default(draft) _pp

  |

  o  3:a7fdfda64c08@default(draft) _oo

  |

  | o  2:f52200b086ca@default(draft) add uu

  | |

  | x  1:d55647aaa0c6@default(draft) oo+pp

  |/

  o  0:58663bb03074@default(draft) add aa

  $ hg evolve --rev "0::"

  move:[2] add uu

  atop:[4] _pp

  working directory is now at 6f5bbe2e3df3