tests/test-sparse-requirement.t

changegroup: move deltaparent() from narrow

I'm not keen on performing the attribute sniff to test for
presence of ellipses mode: I'd rather we use a separate packer
instance that was ellipses mode specific. But I've tried to
formalize a better API without narrow in core and I can't
make sense of all the monkeypatching. My goal is to inline
as much of the monkeypatching as possible then refactor the
changegroup generation API.

We add this code to the cg2packer because narrow doesn't work
with cg1.

Differential Revision: https://phab.mercurial-scm.org/D4062

  $ 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
  testonly-simplestore (reposimplestore !)

  $ 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
  testonly-simplestore (reposimplestore !)

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
  testonly-simplestore (reposimplestore !)

And client without sparse can access

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