tests/test-rebase-legacy.t

filelog: don't crash on invalid copy metadata (issue5748)

"copy" and "copyrev" are both supposed to appear next to each other.
However, a user report demonstrated a crash that indicates that
something in the wild is producing "copy" without "copyrev"
(probably `hg convert`).

While we should definitely fix the source of the bad metadata,
the bad code causing the crash is already in the wild and who knows
how many repositories are impacted. So let's be more defensive
when accessing the file revision metadata.

Test rebase --continue with rebasestate written by legacy client

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

  $ hg init
  $ hg debugdrawdag <<'EOF'
  >    D H
  >    | |
  >    C G
  >    | |
  >    B F
  >    | |
  >  Z A E
  >   \|/
  >    R
  > EOF

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
  > f424eb6a8c01c4a0c0fba9f863f79b3eb5b4b69f
  > 0000000000000000000000000000000000000000
  > 0
  > 0
  > 0
  > 
  > 21a6c45028857f500f56ae84fbf40689c429305b:-2
  > de008c61a447fcfd93f808ef527d933a84048ce7:0000000000000000000000000000000000000000
  > c1e6b162678d07d0b204e5c8267d51b4e03b633c:0000000000000000000000000000000000000000
  > aeba276fcb7df8e10153a07ee728d5540693f5aa:-3
  > bd5548558fcf354d37613005737a143871bf3723:-3
  > d2fa1c02b2401b0e32867f26cce50818a4bd796a:0000000000000000000000000000000000000000
  > 6f7a236de6852570cd54649ab62b1012bb78abc8:0000000000000000000000000000000000000000
  > 6582e6951a9c48c236f746f186378e36f59f4928:0000000000000000000000000000000000000000
  > EOF

  $ hg rebase --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" (H tip)
  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