view tests/test-dirstate-version-fallback.t @ 51580:b70628a9aa7e

phases: use revision number in new_heads

All graph operations will be done using revision numbers, so passing nodes only
means they will eventually get converted to revision numbers internally.

As part of an effort to align the code on using revision number we make the
`phases.newheads` function operated on revision number, taking them as input
and using them in returns, instead of the node-id it used to consume and
produce.

This is part of multiple changesets effort to translate more part of the logic,
but is done step by step to facilitate the identification of issue that might
arise in mercurial core and extensions.

To make the change simpler to handle for third party extensions, we also rename
the function, using a more modern form. This will help detecting the different
between the node-id version and the rev-num version.

I also take this as an opportunity to add some comment about possible
performance improvement for the future. They don't matter too much now, but they
are worse exploring in a while.

  $ cat >> $HGRCPATH << EOF
  > [storage]
  > dirstate-v2.slow-path=allow
  > [format]
  > use-dirstate-v2=no
  > EOF

Set up a v1 repo

  $ hg init repo
  $ cd repo
  $ echo a > a
  $ touch file-with-somewhat-long-name-to-make-dirstate-v1-bigger-than-v2
  $ hg commit -Aqm a
  $ hg debugrequires | grep dirstate
  [1]
  $ ls -1 .hg/dirstate*
  .hg/dirstate

Copy v1 dirstate
  $ cp .hg/dirstate $TESTTMP/dirstate-v1-backup

Upgrade it to v2

  $ hg debugupgraderepo -q --config format.use-dirstate-v2=1 --run | grep -E 'added:|removed:'
     added: dirstate-v2
  $ hg debugrequires | grep dirstate
  dirstate-v2
  $ ls -1 .hg/dirstate*
  .hg/dirstate
  .hg/dirstate.* (glob)

Manually reset to dirstate v1 to simulate an incomplete dirstate-v2 upgrade

  $ rm .hg/dirstate*
  $ cp $TESTTMP/dirstate-v1-backup .hg/dirstate

There should be no errors, but a v2 dirstate should be written back to disk
  $ hg st
  $ ls -1 .hg/dirstate*
  .hg/dirstate
  .hg/dirstate.* (glob)

Corrupt the dirstate to see how the errors show up to the user
  $ echo "I ate your data" > .hg/dirstate

  $ hg st
  abort: working directory state appears damaged! (no-rhg !)
  (falling back to dirstate-v1 from v2 also failed) (no-rhg !)
  abort: Too little data for dirstate: 16 bytes. (rhg !)
  [255]