tests/test-revlog-v2.t

bundle: add config option to include phases

This adds an experimental.bundle-phases config option to include phase
information in bundles. As with the recently added support for
bundling obsmarkers, the support for bundling phases is hidden behind
the config option until we decide to make a bundlespec v3 that
includes phases (and obsmarkers and ...).

We could perhaps use the listkeys format for this, but that's
considered obsolete according to Pierre-Yves. Instead, we introduce a
new "phase-heads" bundle part. The new part contains the phase heads
among the set of bundled revisions. It does not include those in
secret phase; any head in the bundle that is not mentioned in the
phase-heads part is assumed to be secret. As a special case, an empty
phase-heads part thus means that any changesets should be added in
secret phase. (If we ever add a fourth phase, we'll include secret in
the part and we'll add a version number.)

For now, phases are only included by "hg bundle", and not by
e.g. strip and rebase.

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 empty-repo
  $ cd empty-repo
  $ cat .hg/requires
  dotencode
  exp-revlogv2.0
  fncache
  store

  $ hg log

Unknown flags to revlog are rejected

  >>> with open('.hg/store/00changelog.i', 'wb') as fh:
  ...     fh.write('\x00\x04\xde\xad')

  $ hg log
  abort: unknown flags (0x04) in version 57005 revlog 00changelog.i!
  [255]

  $ 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 (changelog always disables generaldelta)

  $ f --hexdump --bytes 4 .hg/store/00changelog.i
  .hg/store/00changelog.i:
  0000: 00 01 de ad                                     |....|

  $ f --hexdump --bytes 4 .hg/store/data/foo.i
  .hg/store/data/foo.i:
  0000: 00 03 de ad                                     |....|