tests/test-sidedata.t

revlog: make the index always return the same tuple

It is simpler to manage the diferrence in on disk format in the internal index
code itself and lets the rest of the code always handle the same object.

This will become even more important when the data we store will be entirely
different (for example the changelog does not need the "linkrev" field.

We start with item reading, we will deal with item writing in the next
changesets.

Differential Revision: https://phab.mercurial-scm.org/D10568

==========================================================
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
  share-safe:          no     no      no
  sparserevlog:       yes    yes     yes
  persistent-nodemap:  no     no      no (no-rust !)
  persistent-nodemap: yes    yes      no (rust !)
  copies-sdc:          no     no      no
  revlog-v2:           no     no      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib (no-zstd !)
  compression:        zstd   zstd    zstd (zstd !)
  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
  share-safe:          no     no      no
  sparserevlog:       yes    yes     yes
  persistent-nodemap:  no     no      no (no-rust !)
  persistent-nodemap: yes    yes      no (rust !)
  copies-sdc:          no     no      no
  revlog-v2:           no    yes      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib (no-zstd !)
  compression:        zstd   zstd    zstd (zstd !)
  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
  share-safe:          no     no      no
  sparserevlog:       yes    yes     yes
  persistent-nodemap:  no     no      no (no-rust !)
  persistent-nodemap: yes    yes      no (rust !)
  copies-sdc:          no     no      no
  revlog-v2:          yes     no      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib (no-zstd !)
  compression:        zstd   zstd    zstd (zstd !)
  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
  share-safe:          no     no      no
  sparserevlog:       yes    yes     yes
  persistent-nodemap:  no     no      no (no-rust !)
  persistent-nodemap: yes    yes      no (rust !)
  copies-sdc:          no     no      no
  revlog-v2:          yes     no      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib (no-zstd !)
  compression:        zstd   zstd    zstd (zstd !)
  compression-level:  default default default
  $ hg debugupgraderepo -R up-side-data --config format.exp-use-side-data=no > /dev/null