view tests/test-histedit-non-commute.t @ 32697:19b9fc40cc51

revlog: skeleton support for version 2 revlogs

There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.

It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.

This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.

An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.

To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.

Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.

There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.

  $ . "$TESTDIR/histedit-helpers.sh"

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > histedit=
  > EOF

  $ initrepo ()
  > {
  >     hg init $1
  >     cd $1
  >     for x in a b c d e f ; do
  >         echo $x$x$x$x$x > $x
  >         hg add $x
  >     done
  >     hg ci -m 'Initial commit'
  >     for x in a b c d e f ; do
  >         echo $x > $x
  >         hg ci -m $x
  >     done
  >     echo 'I can haz no commute' > e
  >     hg ci -m 'does not commute with e'
  >     cd ..
  > }

  $ initrepo r1
  $ cd r1

Initial generation of the command files

  $ EDITED="$TESTTMP/editedhistory"
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 3 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 4 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 7 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 5 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 6 >> $EDITED
  $ cat $EDITED
  pick 65a9a84f33fd 3 c
  pick 00f1c5383965 4 d
  pick 39522b764e3d 7 does not commute with e
  pick 7b4e2f4b7bcd 5 e
  pick 500cac37a696 6 f

log before edit
  $ hg log --graph
  @  changeset:   7:39522b764e3d
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   6:500cac37a696
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:7b4e2f4b7bcd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     e
  |
  o  changeset:   4:00f1c5383965
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:65a9a84f33fd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:da6535b52e45
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:c1f09da44841
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

edit the history
  $ hg histedit 3 --commands $EDITED 2>&1 | fixbundle
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 39522b764e3d)
  (hg histedit --continue to resume)

abort the edit
  $ hg histedit --abort 2>&1 | fixbundle
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved


second edit set

  $ hg log --graph
  @  changeset:   7:39522b764e3d
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   6:500cac37a696
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:7b4e2f4b7bcd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     e
  |
  o  changeset:   4:00f1c5383965
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:65a9a84f33fd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:da6535b52e45
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:c1f09da44841
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

edit the history
  $ hg histedit 3 --commands $EDITED 2>&1 | fixbundle
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 39522b764e3d)
  (hg histedit --continue to resume)

fix up
  $ echo 'I can haz no commute' > e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 7b4e2f4b7bcd)
  (hg histedit --continue to resume)
  $ hg histedit --continue 2>&1 | fixbundle
  abort: unresolved merge conflicts (see 'hg help resolve')

This failure is caused by 7b4e2f4b7bcd "e" not rebasing the non commutative
former children.

just continue this time
  $ hg revert -r 'p1()' e
make sure the to-be-empty commit doesn't screw up the state (issue5545)
  $ hg histedit --continue 2>&1 | fixbundle
  abort: unresolved merge conflicts (see 'hg help resolve')
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle
  7b4e2f4b7bcd: skipping changeset (no changes)

log after edit
  $ hg log --graph
  @  changeset:   6:7efe1373e4bc
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:e334d87a1e55
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   4:00f1c5383965
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:65a9a84f33fd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:da6535b52e45
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:c1f09da44841
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

start over

  $ cd ..

  $ initrepo r2
  $ cd r2
  $ rm $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 3 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 4 >> $EDITED
  $ hg log --template 'mess {node|short} {rev} {desc}\n' -r 7 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 5 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 6 >> $EDITED
  $ cat $EDITED
  pick 65a9a84f33fd 3 c
  pick 00f1c5383965 4 d
  mess 39522b764e3d 7 does not commute with e
  pick 7b4e2f4b7bcd 5 e
  pick 500cac37a696 6 f

edit the history, this time with a fold action
  $ hg histedit 3 --commands $EDITED 2>&1 | fixbundle
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (mess 39522b764e3d)
  (hg histedit --continue to resume)

  $ echo 'I can haz no commute' > e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 7b4e2f4b7bcd)
  (hg histedit --continue to resume)
second edit also fails, but just continue
  $ hg revert -r 'p1()' e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle
  7b4e2f4b7bcd: skipping changeset (no changes)

post message fix
  $ hg log --graph
  @  changeset:   6:7efe1373e4bc
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:e334d87a1e55
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   4:00f1c5383965
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:65a9a84f33fd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:da6535b52e45
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:c1f09da44841
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

  $ cd ..