tests/test-sparse-requirement.t

scmutil: handle conflicting files and dirs in origbackuppath

When ui.origbackuppath is set, .orig files are stored outside of the working
copy.  However conflicts can occur when files or directories end up having the
same name.  These conflicts cause Mercurial to abort, even if they've been
created as a result of different backups.

Make sure we always replace files or directories in the origbackuppath if
they conflict with another file or directory.

Test Plan:
Add new unit test for conflicting paths.

Differential Revision: https://phab.mercurial-scm.org/D680

  $ hg init repo
  $ cd repo

  $ touch a.html b.html c.py d.py

  $ cat > frontend.sparse << EOF
  > [include]
  > *.html
  > EOF

  $ hg -q commit -A -m initial

  $ echo 1 > a.html
  $ echo 1 > c.py
  $ hg commit -m 'commit 1'

Enable sparse profile

  $ cat .hg/requires
  dotencode
  fncache
  generaldelta
  revlogv1
  store

  $ hg debugsparse --config extensions.sparse= --enable-profile frontend.sparse
  $ ls
  a.html
  b.html

Requirement for sparse added when sparse is enabled

  $ cat .hg/requires
  dotencode
  exp-sparse
  fncache
  generaldelta
  revlogv1
  store

Client without sparse enabled reacts properly

  $ hg files
  abort: repository is using sparse feature but sparse is not enabled; enable the "sparse" extensions to access!
  [255]

Requirement for sparse is removed when sparse is disabled

  $ hg debugsparse --reset --config extensions.sparse=

  $ cat .hg/requires
  dotencode
  fncache
  generaldelta
  revlogv1
  store

And client without sparse can access

  $ hg files
  a.html
  b.html
  c.py
  d.py
  frontend.sparse