view tests/test-identify.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outdated and unsupported repo format.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.

#require serve

#if no-outer-repo

no repo

  $ hg id
  abort: there is no Mercurial repository here (.hg not found)
  [255]

#endif

create repo

  $ hg init test
  $ cd test
  $ echo a > a
  $ hg ci -Ama
  adding a

basic id usage

  $ hg id
  cb9a9f314b8b tip
  $ hg id --debug
  cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b tip
  $ hg id -q
  cb9a9f314b8b
  $ hg id -v
  cb9a9f314b8b tip

with options

  $ hg id -r.
  cb9a9f314b8b tip
  $ hg id -n
  0
  $ hg id -t
  tip
  $ hg id -b
  default
  $ hg id -i
  cb9a9f314b8b
  $ hg id -n -t -b -i
  cb9a9f314b8b 0 default tip

with modifications

  $ echo b > a
  $ hg id -n -t -b -i
  cb9a9f314b8b+ 0+ default tip

other local repo

  $ cd ..
  $ hg -R test id
  cb9a9f314b8b+ tip
#if no-outer-repo
  $ hg id test
  cb9a9f314b8b+ tip
#endif

with remote http repo

  $ cd test
  $ hg serve -p $HGPORT1 -d --pid-file=hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ hg id http://localhost:$HGPORT1/
  cb9a9f314b8b

remote with rev number?

  $ hg id -n http://localhost:$HGPORT1/
  abort: can't query remote revision number, branch, or tags
  [255]

remote with tags?

  $ hg id -t http://localhost:$HGPORT1/
  abort: can't query remote revision number, branch, or tags
  [255]

remote with branch?

  $ hg id -b http://localhost:$HGPORT1/
  abort: can't query remote revision number, branch, or tags
  [255]

test bookmark support

  $ hg bookmark Y
  $ hg bookmark Z
  $ hg bookmarks
     Y                         0:cb9a9f314b8b
   * Z                         0:cb9a9f314b8b
  $ hg id
  cb9a9f314b8b+ tip Y/Z
  $ hg id --bookmarks
  Y Z

test remote identify with bookmarks

  $ hg id http://localhost:$HGPORT1/
  cb9a9f314b8b Y/Z
  $ hg id --bookmarks http://localhost:$HGPORT1/
  Y Z
  $ hg id -r . http://localhost:$HGPORT1/
  cb9a9f314b8b Y/Z
  $ hg id --bookmarks -r . http://localhost:$HGPORT1/
  Y Z

test invalid lookup

  $ hg id -r noNoNO http://localhost:$HGPORT1/
  abort: unknown revision 'noNoNO'!
  [255]

Make sure we do not obscure unknown requires file entries (issue2649)

  $ echo fake >> .hg/requires
  $ hg id
  abort: repository requires features unknown to this Mercurial: fake!
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]

  $ cd ..
#if no-outer-repo
  $ hg id test
  abort: repository requires features unknown to this Mercurial: fake!
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]
#endif