tests/test-rebase-legacy.t

dirstate-v2: add check of parent/child nodes being related when writing

This stems from a corruption seen in a private repository. We're not sure
of the source of the corruption, and it's very possible that we're seeing
compounded effects of multiple writes on a corrupted dirstate.

Adding this check is not expensive in itself and large writes of the dirstate
are not common.

This change does not catch this problem at the root node, the next one will.

#testcases continuecommand continueflag
Test rebase --continue with rebasestate written by legacy client

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > drawdag=$TESTDIR/drawdag.py
  > EOF

#if continueflag
  $ cat >> $HGRCPATH <<EOF
  > [alias]
  > continue = rebase --continue
  > EOF
#endif

  $ hg init
  $ hg debugdrawdag <<'EOF'
  >    D H
  >    | |
  >    C G
  >    | |
  >    B F
  >    | |
  >  Z A E
  >   \|/
  >    R
  > EOF
  $ for r in A B C D E F G H R Z
  > do
  >   eval node_$r=$(hg log -r $r -T '{node}')
  > done

rebasestate generated by a legacy client running "hg rebase -r B+D+E+G+H -d Z"

  $ touch .hg/last-message.txt
  $ cat > .hg/rebasestate <<EOF
  > 0000000000000000000000000000000000000000
  > $node_Z
  > 0000000000000000000000000000000000000000
  > 0
  > 0
  > 0
  > 
  > $node_A:-2
  > $node_E:0000000000000000000000000000000000000000
  > $node_B:0000000000000000000000000000000000000000
  > $node_F:-3
  > $node_C:-3
  > $node_G:0000000000000000000000000000000000000000
  > $node_D:0000000000000000000000000000000000000000
  > $node_H:0000000000000000000000000000000000000000
  > EOF

#if continuecommand
  $ hg continue --dry-run
  rebase in progress, will be resumed
#endif

  $ hg continue
  rebasing 4:c1e6b162678d B "B"
  rebasing 8:6f7a236de685 D "D"
  rebasing 2:de008c61a447 E "E"
  rebasing 7:d2fa1c02b240 G "G"
  rebasing 9:6582e6951a9c H tip "H"
  warning: orphaned descendants detected, not stripping c1e6b162678d, de008c61a447
  saved backup bundle to $TESTTMP/.hg/strip-backup/6f7a236de685-9880a3dc-rebase.hg

  $ hg log -G -T '{rev}:{node|short} {desc}\n'
  o  11:721b8da0a708 H
  |
  o  10:9d65695ec3c2 G
  |
  o  9:21c8397a5d68 E
  |
  | o  8:fc52970345e8 D
  | |
  | o  7:eac96551b107 B
  |/
  | o  6:bd5548558fcf C
  | |
  | | o  5:aeba276fcb7d F
  | | |
  | o |  4:c1e6b162678d B
  | | |
  o | |  3:f424eb6a8c01 Z
  | | |
  +---o  2:de008c61a447 E
  | |
  | o  1:21a6c4502885 A
  |/
  o  0:b41ce7760717 R