tests/test-mq-symlinks.t

phases: large rewrite on retract boundary

The new code is still pure Python, so we still have room to going significantly
faster. However its complexity of the complex part is `O(|[min_new_draft, tip]|)` instead of
`O(|[min_draft, tip]|` which should help tremendously one repository with old
draft (like mercurial-devel or mozilla-try).

This is especially useful as the most common "retract boundary" operation
happens when we commit/rewrite new drafts or when we push new draft to a
non-publishing server. In this case, the smallest new_revs is very close to the
tip and there is very few work to do.

A few smaller optimisation could be done for these cases and will be introduced in
later changesets.

We still have iterate over large sets of roots, but this is already a great
improvement for a very small amount of work. We gather information on the
affected changeset as we go as we can put it to use in the next changesets.
This extra data collection might slowdown the `register_new` case a bit, however
for register_new, it should not really matters. The set of new nodes is either
small, so the impact is negligible, or the set of new nodes is large, and the
amount of work to do to had them will dominate the overhead the collecting
information in `changed_revs`.

As this new code compute the changes on the fly, it unlock other interesting
improvement to be done in later changeset.

#require symlink

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init repo
  $ cd repo
  $ hg qinit
  $ hg qnew base.patch
  $ echo aaa > a
  $ echo bbb > b
  $ echo ccc > c
  $ hg add a b c
  $ hg qrefresh
  $ readlink.py a
  a -> a not a symlink


test replacing a file with a symlink

  $ hg qnew symlink.patch
  $ rm a
  $ ln -s b a
  $ hg qrefresh --git
  $ readlink.py a
  a -> b

  $ hg qpop
  popping symlink.patch
  now at: base.patch
  $ hg qpush
  applying symlink.patch
  now at: symlink.patch
  $ readlink.py a
  a -> b


test updating a symlink

  $ rm a
  $ ln -s c a
  $ hg qnew --git -f updatelink
  $ readlink.py a
  a -> c
  $ hg qpop
  popping updatelink
  now at: symlink.patch
  $ hg qpush --debug
  applying updatelink
  patching file a
  committing files:
  a
  committing manifest
  committing changelog
  updating the branch cache
  now at: updatelink
  $ readlink.py a
  a -> c
  $ hg st


test replacing a symlink with a file

  $ ln -s c s
  $ hg add s
  $ hg qnew --git -f addlink
  $ rm s
  $ echo sss > s
  $ hg qnew --git -f replacelinkwithfile
  $ hg qpop
  popping replacelinkwithfile
  now at: addlink
  $ hg qpush
  applying replacelinkwithfile
  now at: replacelinkwithfile
  $ cat s
  sss
  $ hg st


test symlink removal

  $ hg qnew removesl.patch
  $ hg rm a
  $ hg qrefresh --git
  $ hg qpop
  popping removesl.patch
  now at: replacelinkwithfile
  $ hg qpush
  applying removesl.patch
  now at: removesl.patch
  $ hg st -c
  C b
  C c
  C s

replace broken symlink with another broken symlink

  $ ln -s linka linka
  $ hg add linka
  $ hg qnew link
  $ hg mv linka linkb
  $ rm linkb
  $ ln -s linkb linkb
  $ hg qnew movelink
  $ hg qpop
  popping movelink
  now at: link
  $ hg qpush
  applying movelink
  now at: movelink
  $ readlink.py linkb
  linkb -> linkb