view tests/test-merge-local.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.

  $ hg init

Revision 0:

  $ echo "unchanged" > unchanged
  $ echo "remove me" > remove
  $ echo "copy me" > copy
  $ echo "move me" > move
  $ for i in 1 2 3 4 5 6 7 8 9; do
  >     echo "merge ok $i" >> zzz1_merge_ok
  > done
  $ echo "merge bad" > zzz2_merge_bad
  $ hg ci -Am "revision 0"
  adding copy
  adding move
  adding remove
  adding unchanged
  adding zzz1_merge_ok
  adding zzz2_merge_bad

Revision 1:

  $ hg rm remove
  $ hg mv move moved
  $ hg cp copy copied
  $ echo "added" > added
  $ hg add added
  $ echo "new first line" > zzz1_merge_ok
  $ hg cat zzz1_merge_ok >> zzz1_merge_ok
  $ echo "new last line" >> zzz2_merge_bad
  $ hg ci -m "revision 1"

Local changes to revision 0:

  $ hg co 0
  4 files updated, 0 files merged, 3 files removed, 0 files unresolved
  $ echo "new last line" >> zzz1_merge_ok
  $ echo "another last line" >> zzz2_merge_bad

  $ hg diff --nodates | grep "^[+-][^<>]"
  --- a/zzz1_merge_ok
  +++ b/zzz1_merge_ok
  +new last line
  --- a/zzz2_merge_bad
  +++ b/zzz2_merge_bad
  +another last line

  $ hg st
  M zzz1_merge_ok
  M zzz2_merge_bad

Local merge with bad merge tool:

  $ HGMERGE=false hg co
  merging zzz1_merge_ok
  merging zzz2_merge_bad
  merging zzz2_merge_bad failed!
  3 files updated, 1 files merged, 2 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges
  [1]

  $ hg co 0
  merging zzz1_merge_ok
  merging zzz2_merge_bad
  warning: conflicts while merging zzz2_merge_bad! (edit, then use 'hg resolve --mark')
  2 files updated, 1 files merged, 3 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges
  [1]

  $ hg diff --nodates | grep "^[+-][^<>]"
  --- a/zzz1_merge_ok
  +++ b/zzz1_merge_ok
  +new last line
  --- a/zzz2_merge_bad
  +++ b/zzz2_merge_bad
  +another last line
  +=======

  $ hg st
  M zzz1_merge_ok
  M zzz2_merge_bad
  ? zzz2_merge_bad.orig

Local merge with conflicts:

  $ hg co
  merging zzz1_merge_ok
  merging zzz2_merge_bad
  warning: conflicts while merging zzz2_merge_bad! (edit, then use 'hg resolve --mark')
  3 files updated, 1 files merged, 2 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges
  [1]

  $ hg co 0
  merging zzz1_merge_ok
  merging zzz2_merge_bad
  warning: conflicts while merging zzz2_merge_bad! (edit, then use 'hg resolve --mark')
  2 files updated, 1 files merged, 3 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges
  [1]

  $ hg diff --nodates | grep "^[+-][^<>]"
  --- a/zzz1_merge_ok
  +++ b/zzz1_merge_ok
  +new last line
  --- a/zzz2_merge_bad
  +++ b/zzz2_merge_bad
  +another last line
  +=======
  +=======
  +new last line
  +=======

  $ hg st
  M zzz1_merge_ok
  M zzz2_merge_bad
  ? zzz2_merge_bad.orig

Local merge without conflicts:

  $ hg revert zzz2_merge_bad

  $ hg co
  merging zzz1_merge_ok
  4 files updated, 1 files merged, 2 files removed, 0 files unresolved

  $ hg diff --nodates | grep "^[+-][^<>]"
  --- a/zzz1_merge_ok
  +++ b/zzz1_merge_ok
  +new last line

  $ hg st
  M zzz1_merge_ok
  ? zzz2_merge_bad.orig