tests/test-sidedata.t

mergestate: introduce a new ACTION_KEEP_NEW

`ACTION_KEEP` is overloaded and it's hard to figure out how we end up with this
KEEP, what was the state of things.

In a previous patch, we introduced `ACTION_KEEP_ABSENT` which represents files
which are kept absent in the working directory.

There is another special case where we keep the file when it's not present on
both ancestor and remote side. We introduce a dedicated action for that.

The goal is to use these information to make bid merge smarter.

Differential Revision: https://phab.mercurial-scm.org/D9002

==========================================================
Test file dedicated to checking side-data related behavior
==========================================================

Check data can be written/read from sidedata
============================================

  $ cat << EOF >> $HGRCPATH
  > [extensions]
  > testsidedata=$TESTDIR/testlib/ext-sidedata.py
  > EOF

  $ hg init test-sidedata --config format.exp-use-side-data=yes
  $ cd test-sidedata
  $ echo aaa > a
  $ hg add a
  $ hg commit -m a --traceback
  $ echo aaa > b
  $ hg add b
  $ hg commit -m b
  $ echo xxx >> a
  $ hg commit -m aa

  $ hg debugsidedata -c 0
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg debugsidedata -c 1 -v
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x006'
   entry-0002 size 32
    '\x98\t\xf9\xc4v\xf0\xc5P\x90\xf7wRf\xe8\xe27e\xfc\xc1\x93\xa4\x96\xd0\x1d\x97\xaaG\x1d\xd7t\xfa\xde'
  $ hg debugsidedata -m 2
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg debugsidedata a  1
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32

Check upgrade behavior
======================

Right now, sidedata has not upgrade support

Check that we can upgrade to sidedata
-------------------------------------

  $ hg init up-no-side-data --config format.exp-use-side-data=no
  $ hg debugformat -v -R up-no-side-data
  format-variant     repo config default
  fncache:            yes    yes     yes
  dotencode:          yes    yes     yes
  generaldelta:       yes    yes     yes
  sparserevlog:       yes    yes     yes
  sidedata:            no     no      no
  persistent-nodemap:  no     no      no
  copies-sdc:          no     no      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib
  compression-level:  default default default
  $ hg debugformat -v -R up-no-side-data --config format.exp-use-side-data=yes
  format-variant     repo config default
  fncache:            yes    yes     yes
  dotencode:          yes    yes     yes
  generaldelta:       yes    yes     yes
  sparserevlog:       yes    yes     yes
  sidedata:            no    yes      no
  persistent-nodemap:  no     no      no
  copies-sdc:          no     no      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib
  compression-level:  default default default
  $ hg debugupgraderepo -R up-no-side-data --config format.exp-use-side-data=yes > /dev/null

Check that we can downgrade from sidedata
-----------------------------------------

  $ hg init up-side-data --config format.exp-use-side-data=yes
  $ hg debugformat -v -R up-side-data
  format-variant     repo config default
  fncache:            yes    yes     yes
  dotencode:          yes    yes     yes
  generaldelta:       yes    yes     yes
  sparserevlog:       yes    yes     yes
  sidedata:           yes     no      no
  persistent-nodemap:  no     no      no
  copies-sdc:          no     no      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib
  compression-level:  default default default
  $ hg debugformat -v -R up-side-data --config format.exp-use-side-data=no
  format-variant     repo config default
  fncache:            yes    yes     yes
  dotencode:          yes    yes     yes
  generaldelta:       yes    yes     yes
  sparserevlog:       yes    yes     yes
  sidedata:           yes     no      no
  persistent-nodemap:  no     no      no
  copies-sdc:          no     no      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib
  compression-level:  default default default
  $ hg debugupgraderepo -R up-side-data --config format.exp-use-side-data=no > /dev/null