tests/test-rebase-check-restore.t

filectx: add isabsent method

This will indicate whether this filectx represents a file that is *not* in a
changectx. This will be used by merge and filemerge code to know about when a
conflict is a change/delete conflict.

While this is kind of hacky, it is the least bad of all the alternatives. Other
options considered but rejected include:
- isinstance(fctx, ...) -- not very Pythonic, doesn't support duck typing
- fctx.size() is None -- the 'size()' call on workingfilectxes causes a disk stat
- fctx.filenode() == nullid -- the semantics around filenode are incredibly
  confusing. In particular, for workingfilectxes, filenode() is always None no
  matter whether the file is present on disk or in either parent. Having different
  behavior for None versus nullid in the merge code is just asking for pain.

Thanks to Pierre-Yves David for early review feedback here.

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > 
  > [phases]
  > publish=False
  > 
  > [alias]
  > tglog = log -G --template "{rev}:{phase} '{desc}' {branches}\n"
  > EOF


  $ hg init a
  $ cd a

  $ echo A > A
  $ hg add A
  $ hg ci -m A

  $ echo 'B' > B
  $ hg add B
  $ hg ci -m B

  $ echo C >> A
  $ hg ci -m C

  $ hg up -q -C 0

  $ echo D >> A
  $ hg ci -m D
  created new head

  $ echo E > E
  $ hg add E
  $ hg ci -m E

  $ hg up -q -C 0

  $ hg branch 'notdefault'
  marked working directory as branch notdefault
  (branches are permanent and global, did you want a bookmark?)
  $ echo F >> A
  $ hg ci -m F

  $ cd ..


Rebasing B onto E - check keep: and phases

  $ hg clone -q -u . a a1
  $ cd a1
  $ hg phase --force --secret 2

  $ hg tglog
  @  5:draft 'F' notdefault
  |
  | o  4:draft 'E'
  | |
  | o  3:draft 'D'
  |/
  | o  2:secret 'C'
  | |
  | o  1:draft 'B'
  |/
  o  0:draft 'A'
  
  $ hg rebase -s 1 -d 4 --keep
  rebasing 1:27547f69f254 "B"
  rebasing 2:965c486023db "C"
  merging A
  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

Solve the conflict and go on:

  $ echo 'conflict solved' > A
  $ rm A.orig
  $ hg resolve -m A
  (no more unresolved files)
  $ hg rebase --continue
  already rebased 1:27547f69f254 "B" as 45396c49d53b
  rebasing 2:965c486023db "C"

  $ hg tglog
  o  7:secret 'C'
  |
  o  6:draft 'B'
  |
  | @  5:draft 'F' notdefault
  | |
  o |  4:draft 'E'
  | |
  o |  3:draft 'D'
  |/
  | o  2:secret 'C'
  | |
  | o  1:draft 'B'
  |/
  o  0:draft 'A'
  
  $ cd ..


Rebase F onto E - check keepbranches:

  $ hg clone -q -u . a a2
  $ cd a2
  $ hg phase --force --secret 2

  $ hg tglog
  @  5:draft 'F' notdefault
  |
  | o  4:draft 'E'
  | |
  | o  3:draft 'D'
  |/
  | o  2:secret 'C'
  | |
  | o  1:draft 'B'
  |/
  o  0:draft 'A'
  
  $ hg rebase -s 5 -d 4 --keepbranches
  rebasing 5:01e6ebbd8272 "F" (tip)
  merging A
  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

Solve the conflict and go on:

  $ echo 'conflict solved' > A
  $ rm A.orig
  $ hg resolve -m A
  (no more unresolved files)
  $ hg rebase --continue
  rebasing 5:01e6ebbd8272 "F" (tip)
  saved backup bundle to $TESTTMP/a2/.hg/strip-backup/01e6ebbd8272-6fd3a015-backup.hg (glob)

  $ hg tglog
  @  5:draft 'F' notdefault
  |
  o  4:draft 'E'
  |
  o  3:draft 'D'
  |
  | o  2:secret 'C'
  | |
  | o  1:draft 'B'
  |/
  o  0:draft 'A'
  

  $ cd ..