tests/test-clone-r.t

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outdated and unsupported repo format.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.

  $ hg init test
  $ cd test

  $ echo 0 >> afile
  $ hg add afile
  $ hg commit -m "0.0"

  $ echo 1 >> afile
  $ hg commit -m "0.1"

  $ echo 2 >> afile
  $ hg commit -m "0.2"

  $ echo 3 >> afile
  $ hg commit -m "0.3"

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

  $ echo 1 >> afile
  $ hg commit -m "1.1"
  created new head

  $ echo 2 >> afile
  $ hg commit -m "1.2"

  $ echo a line > fred
  $ echo 3 >> afile
  $ hg add fred
  $ hg commit -m "1.3"
  $ hg mv afile adifferentfile
  $ hg commit -m "1.3m"

  $ hg update -C 3
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved

  $ hg mv afile anotherfile
  $ hg commit -m "0.3m"

  $ hg debugindex -f 1 afile
     rev flag   offset   length     size  .....   link     p1     p2       nodeid (re)
       0 0000        0        3        2  .....      0     -1     -1 362fef284ce2 (re)
       1 0000        3        5        4  .....      1      0     -1 125144f7e028 (re)
       2 0000        8        7        6  .....      2      1     -1 4c982badb186 (re)
       3 0000       15        9        8  .....      3      2     -1 19b1fc555737 (re)

  $ hg debugindex adifferentfile
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0      75  .....       7 2565f3199a74 000000000000 000000000000 (re)

  $ hg debugindex anotherfile
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0      75  .....       8 2565f3199a74 000000000000 000000000000 (re)

  $ hg debugindex fred
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       8  .....       6 12ab3bcc5ea4 000000000000 000000000000 (re)

  $ hg debugindex --manifest
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0      48  .....       0 43eadb1d2d06 000000000000 000000000000 (re)
       1        48      48  .....       1 8b89697eba2c 43eadb1d2d06 000000000000 (re)
       2        96      48  .....       2 626a32663c2f 8b89697eba2c 000000000000 (re)
       3       144      48  .....       3 f54c32f13478 626a32663c2f 000000000000 (re)
       4       192      ..  .....       6 de68e904d169 626a32663c2f 000000000000 (re)
       5       2..      ..  .....       7 09bb521d218d de68e904d169 000000000000 (re)
       6       3..      54  .....       8 1fde233dfb0f f54c32f13478 000000000000 (re)

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  4 files, 9 changesets, 7 total revisions

  $ cd ..

  $ for i in 0 1 2 3 4 5 6 7 8; do
  >   echo
  >   echo ---- hg clone -r "$i" test test-"$i"
  >   hg clone -r "$i" test test-"$i"
  >   cd test-"$i"
  >   hg verify
  >   cd ..
  > done
  
  ---- hg clone -r 0 test test-0
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions
  
  ---- hg clone -r 1 test test-1
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 2 changesets, 2 total revisions
  
  ---- hg clone -r 2 test test-2
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 3 changesets, 3 total revisions
  
  ---- hg clone -r 3 test test-3
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 4 changesets, 4 total revisions
  
  ---- hg clone -r 4 test test-4
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 2 changesets, 2 total revisions
  
  ---- hg clone -r 5 test test-5
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 3 changesets, 3 total revisions
  
  ---- hg clone -r 6 test test-6
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 5 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 4 changesets, 5 total revisions
  
  ---- hg clone -r 7 test test-7
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 6 changes to 3 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  3 files, 5 changesets, 6 total revisions
  
  ---- hg clone -r 8 test test-8
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 2 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 5 changesets, 5 total revisions

  $ cd test-8
  $ hg pull ../test-7
  pulling from ../test-7
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 2 changes to 3 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  4 files, 9 changesets, 7 total revisions
  $ cd ..

  $ hg clone test test-9
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd test-9
  $ hg branch foobar
  marked working directory as branch foobar
  (branches are permanent and global, did you want a bookmark?)
  $ echo file2 >> file2
  $ hg add file2
  $ hg commit -m "changeset9"
  $ echo file3 >> file3
  $ hg add file3
  $ hg commit -m "changeset10"
  $ cd ..
  $ hg clone -r 9 -u foobar test-9 test-10
  adding changesets
  adding manifests
  adding file changes
  added 6 changesets with 6 changes to 3 files
  updating to branch foobar
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved