tests/test-revlog-v2.t

dirstate-v2: freeze the on-disk format

It seems the format as reached a good balance. With a core of new capabilities
that motivated it initially and enough new feature and room for future
improvement to be a clear progress we can set a milestone for.

Having the format frozen will help the feature to get real life testing, outside
of the test suite.

The feature itself stay experimental but the config gains a new name to avoid
people enable non-frozen version by default.

If too many bugs are reported during the RC we might move the format back to
experimental and drop its support in future version (in favor of a new one)

Differential Revision: https://phab.mercurial-scm.org/D11709

#require reporevlogstore

A repo with unknown revlogv2 requirement string cannot be opened

  $ hg init invalidreq
  $ cd invalidreq
  $ echo exp-revlogv2.unknown >> .hg/requires
  $ hg log
  abort: repository requires features unknown to this Mercurial: exp-revlogv2.unknown
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]
  $ cd ..

Can create and open repo with revlog v2 requirement

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > revlogv2 = enable-unstable-format-and-corrupt-my-data
  > EOF

  $ hg init new-repo
  $ cd new-repo
  $ cat .hg/requires
  dotencode
  exp-rc-dirstate-v2 (dirstate-v2 !)
  exp-revlogv2.2
  fncache
  generaldelta
  persistent-nodemap (rust !)
  revlog-compression-zstd (zstd !)
  sparserevlog
  store

  $ hg log

Unknown flags to revlog are rejected

  >>> with open('.hg/store/00changelog.i', 'wb') as fh:
  ...     fh.write(b'\xff\x00\xde\xad') and None

  $ hg log
  abort: unknown flags (0xff00) in version 57005 revlog 00changelog
  [50]

  $ cd ..

Writing a simple revlog v2 works

  $ hg init simple
  $ cd simple
  $ touch foo
  $ hg -q commit -A -m initial

  $ hg log
  changeset:   0:96ee1d7354c4
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     initial
  

Header written as expected

  $ f --hexdump --bytes 4 .hg/store/00changelog.i
  .hg/store/00changelog.i:
  0000: 00 00 de ad                                     |....|

  $ f --hexdump --bytes 4 .hg/store/data/foo.i
  .hg/store/data/foo.i:
  0000: 00 00 de ad                                     |....|

Bundle use a compatible changegroup format
------------------------------------------

  $ hg bundle --all ../basic.hg
  1 changesets found
  $ hg debugbundle --spec ../basic.hg
  bzip2-v2

The expected files are generated
--------------------------------

We should have have:
- a docket
- a index file with a unique name
- a data file

  $ ls .hg/store/00changelog* .hg/store/00manifest*
  .hg/store/00changelog-1335303a.sda
  .hg/store/00changelog-6b8ab34b.idx
  .hg/store/00changelog-b875dfc5.dat
  .hg/store/00changelog.i
  .hg/store/00manifest-05a21d65.idx
  .hg/store/00manifest-43c37dde.dat
  .hg/store/00manifest-e2c9362a.sda
  .hg/store/00manifest.i

Local clone works
-----------------

  $ hg clone . ../cloned-repo
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg tip | tee ../tip-new
  changeset:   0:96ee1d7354c4
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     initial
  
  $ hg tip -R ../cloned-repo | tee ../tip-cloned
  changeset:   0:96ee1d7354c4
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     initial
  

The two repository should be identical, this diff MUST be empty

  $ cmp ../tip-new ../tip-cloned || diff -U8 ../tip-new ../tip-cloned


hg verify should be happy
-------------------------

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files

  $ hg verify -R ../cloned-repo
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files