tests/test-contrib-dumprevlog.t

documentation: add some internals documentation about bid merge

This is an important algorithm that was only documented on the wiki so far.

Some update to the algorithm (and associated doc) is to expected in the future
since the bid merge algorithm is bug-ridden when it comes to file deletion comes
to play.

Differential Revision: https://phab.mercurial-scm.org/D8711

#require reporevlogstore

  $ CONTRIBDIR="$TESTDIR/../contrib"

  $ hg init repo-a
  $ cd repo-a

  $ echo this is file a > a
  $ hg add a
  $ hg commit -m first

  $ echo adding to file a >> a
  $ hg commit -m second

  $ echo adding more to file a >> a
  $ hg commit -m third
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 3 changesets with 3 changes to 1 files

Dumping revlog of file a to stdout:
  $ "$PYTHON" "$CONTRIBDIR/dumprevlog" .hg/store/data/a.i
  file: .hg/store/data/a.i
  node: 183d2312b35066fb6b3b449b84efc370d50993d0
  linkrev: 0
  parents: 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000
  length: 15
  -start-
  this is file a
  
  -end-
  node: b1047953b6e6b633c0d8197eaa5116fbdfd3095b
  linkrev: 1
  parents: 183d2312b35066fb6b3b449b84efc370d50993d0 0000000000000000000000000000000000000000
  length: 32
  -start-
  this is file a
  adding to file a
  
  -end-
  node: 8c4fd1f7129b8cdec6c7f58bf48fb5237a4030c1
  linkrev: 2
  parents: b1047953b6e6b633c0d8197eaa5116fbdfd3095b 0000000000000000000000000000000000000000
  length: 54
  -start-
  this is file a
  adding to file a
  adding more to file a
  
  -end-

Dump all revlogs to file repo.dump:

  $ find .hg/store -name "*.i" | sort | xargs "$PYTHON" "$CONTRIBDIR/dumprevlog" > ../repo.dump
  $ cd ..

Undumping into repo-b:

  $ hg init repo-b
  $ cd repo-b
  $ "$PYTHON" "$CONTRIBDIR/undumprevlog" < ../repo.dump
  .hg/store/00changelog.i
  .hg/store/00manifest.i
  .hg/store/data/a.i
  $ cd ..

Rebuild fncache with clone --pull:

  $ hg clone --pull -U repo-b repo-c
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  new changesets de1da620e7d8:46946d278c50

Verify:

  $ hg -R repo-c verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 3 changesets with 3 changes to 1 files

Compare repos:

  $ hg -R repo-c incoming repo-a
  comparing with repo-a
  searching for changes
  no changes found
  [1]

  $ hg -R repo-a incoming repo-c
  comparing with repo-c
  searching for changes
  no changes found
  [1]