view tests/test-issue672.t @ 26631:e077ce385609

localrepo: restore dirstate to one before rollbacking if not parent-gone

'localrepository.rollback()' explicilty restores dirstate, only if at
least one of current parents of the working directory is removed at
rollbacking (a.k.a "parent-gone").

After DirstateTransactionPlan, 'dirstate.write()' will cause marking
'.hg/dirstate' as a file to be restored at rollbacking.

    https://mercurial.selenic.com/wiki/DirstateTransactionPlan

Then, 'transaction.rollback()' restores '.hg/dirstate' regardless of
parents of the working directory at that time, and this causes
unexpected dirstate changes if not "parent-gone" (e.g.  "hg update" to
another branch after "hg commit" or so, then "hg rollback").

To avoid such situation, this patch restores dirstate to one before
rollbacking if not "parent-gone".

  before:
    b1. restore dirstate explicitly, if "parent-gone"

  after:
    a1. save dirstate before actual rollbacking via dirstateguard
    a2. restore dirstate via 'transaction.rollback()'
    a3. if "parent-gone"
        - discard backup (a1)
        - restore dirstate from 'undo.dirstate'
    a4. otherwise, restore dirstate from backup (a1)

Even though restoring dirstate at (a3) after (a2) seems redundant,
this patch keeps this existing code path, because:

  - it isn't ensured that 'dirstate.write()' was invoked at least once
    while transaction running

    If not, '.hg/dirstate' isn't restored at (a2).

    In addition to it, rude 3rd party extension invoking
    'dirstate.write()' without 'repo' while transaction running (see
    subsequent patches for detail) may break consistency of a file
    backup-ed by transaction.

  - this patch mainly focuses on changes for DirstateTransactionPlan

    Restoring dirstate at (a3) itself should be cheaper enough than
    rollbacking itself. Redundancy will be removed in next step.

Newly added test is almost meaningless at this point. It will be used
to detect regression while implementing delayed dirstate write out.

https://bz.mercurial-scm.org/672

# 0-2-4
#  \ \ \
#   1-3-5
#
# rename in #1, content change in #4.

  $ hg init

  $ touch 1
  $ touch 2
  $ hg commit -Am init  # 0
  adding 1
  adding 2

  $ hg rename 1 1a
  $ hg commit -m rename # 1

  $ hg co -C 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo unrelated >> 2
  $ hg ci -m unrelated1 # 2
  created new head

  $ hg merge --debug 1
    searching for copies back to rev 1
    unmatched files in other:
     1a
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: '1' -> dst: '1a' 
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 81f4b099af3d, local: c64f439569a9+, remote: c12dcd37c90a
   1: other deleted -> r
  removing 1
   1a: remote created -> g
  getting 1a
   2: remote unchanged -> k
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg ci -m merge1 # 3

  $ hg co -C 2
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo hello >> 1
  $ hg ci -m unrelated2 # 4
  created new head

  $ hg co -C 3
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ hg merge -y --debug 4
    searching for copies back to rev 1
    unmatched files in local:
     1a
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: '1' -> dst: '1a' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: c64f439569a9, local: e327dca35ac8+, remote: 746e9549ea96
   preserving 1a for resolve of 1a
   1a: local copied/moved from 1 -> m (premerge)
  picked tool ':merge' for 1a (binary False symlink False)
  merging 1a and 1 to 1a
  my 1a@e327dca35ac8+ other 1@746e9549ea96 ancestor 1@81f4b099af3d
   premerge successful
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg co -C 4
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ hg merge -y --debug 3
    searching for copies back to rev 1
    unmatched files in other:
     1a
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: '1' -> dst: '1a' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: c64f439569a9, local: 746e9549ea96+, remote: e327dca35ac8
   preserving 1 for resolve of 1a
  removing 1
   1a: remote moved from 1 -> m (premerge)
  picked tool ':merge' for 1a (binary False symlink False)
  merging 1 and 1a to 1a
  my 1a@746e9549ea96+ other 1a@e327dca35ac8 ancestor 1@81f4b099af3d
   premerge successful
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)