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
$ . "$TESTDIR/narrow-library.sh"
$ hg init repo
$ cd repo
$ cat << EOF > .hg/store/narrowspec
> [include]
> path:foo
> [exclude]
> EOF
$ cp .hg/store/narrowspec .hg/narrowspec.dirstate
$ echo treemanifest >> .hg/requires
$ echo narrowhg-experimental >> .hg/requires
$ mkdir -p foo/bar
$ echo b > foo/f
$ echo c > foo/bar/f
$ hg commit -Am hi
adding foo/bar/f
adding foo/f
$ hg debugindex -m
rev linkrev nodeid p1 p2
0 0 14a5d056d75a 000000000000 000000000000
$ hg debugindex --dir foo
rev linkrev nodeid p1 p2
0 0 e635c7857aef 000000000000 000000000000
$ hg debugindex --dir foo/
rev linkrev nodeid p1 p2
0 0 e635c7857aef 000000000000 000000000000
$ hg debugindex --dir foo/bar
rev linkrev nodeid p1 p2
0 0 e091d4224761 000000000000 000000000000
$ hg debugindex --dir foo/bar/
rev linkrev nodeid p1 p2
0 0 e091d4224761 000000000000 000000000000
$ hg debugdata -m 0
foo\x00e635c7857aef92ac761ce5741a99da159abbbb24t (esc)
$ hg debugdata --dir foo 0
bar\x00e091d42247613adff5d41b67f15fe7189ee97b39t (esc)
f\x001e88685f5ddec574a34c70af492f95b6debc8741 (esc)
$ hg debugdata --dir foo/ 0
bar\x00e091d42247613adff5d41b67f15fe7189ee97b39t (esc)
f\x001e88685f5ddec574a34c70af492f95b6debc8741 (esc)
$ hg debugdata --dir foo/bar 0
f\x00149da44f2a4e14f488b7bd4157945a9837408c00 (esc)
$ hg debugdata --dir foo/bar/ 0
f\x00149da44f2a4e14f488b7bd4157945a9837408c00 (esc)