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
Test for changeset 9fe267f77f56ff127cf7e65dc15dd9de71ce8ceb
(merge correctly when all the files in a directory are moved
but then local changes are added in the same directory)
$ hg init a
$ cd a
$ mkdir -p testdir
$ echo a > testdir/a
$ hg add testdir/a
$ hg commit -m a
$ cd ..
$ hg clone a b
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd a
$ echo alpha > testdir/a
$ hg commit -m remote-change
$ cd ..
$ cd b
$ mkdir testdir/subdir
$ hg mv testdir/a testdir/subdir/a
$ hg commit -m move
$ mkdir newdir
$ echo beta > newdir/beta
$ hg add newdir/beta
$ hg commit -m local-addition
$ hg pull ../a
pulling from ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets cc7000b01af9
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg up -C 2
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
Abuse this test for also testing that merge respects ui.relative-paths
$ hg --cwd testdir merge --config ui.relative-paths=yes
merging subdir/a and a to subdir/a
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg stat
M testdir/subdir/a
$ hg diff --nodates
diff -r bc21c9773bfa testdir/subdir/a
--- a/testdir/subdir/a
+++ b/testdir/subdir/a
@@ -1,1 +1,1 @@
-a
+alpha
$ cd ..