tests/test-requires.t

pull: avoid race condition with 'hg pull --rev name --update' (issue4706)

The previous scheme was:

1) lookup node for all pulled revision,
2) pull said node
3) lookup the node of the checkout target
4) update the repository there.

If the remote repo changes between (1) and (3), the resolved name will be
different and (3) crash. There is actually no need for a remote lookup during
(3), we could just set the value in (1). This prevent the race condition and
save a possible network roundtrip.

  $ hg init t
  $ cd t
  $ echo a > a
  $ hg add a
  $ hg commit -m test
  $ rm .hg/requires
  $ hg tip
  abort: index 00changelog.i unknown format 2!
  [255]
  $ echo indoor-pool > .hg/requires
  $ hg tip
  abort: repository requires features unknown to this Mercurial: indoor-pool!
  (see http://mercurial.selenic.com/wiki/MissingRequirement for more information)
  [255]
  $ echo outdoor-pool >> .hg/requires
  $ hg tip
  abort: repository requires features unknown to this Mercurial: indoor-pool outdoor-pool!
  (see http://mercurial.selenic.com/wiki/MissingRequirement for more information)
  [255]
  $ cd ..

Test checking between features supported locally and ones required in
another repository of push/pull/clone on localhost:

  $ mkdir supported-locally
  $ cd supported-locally

  $ hg init supported
  $ echo a > supported/a
  $ hg -R supported commit -Am '#0 at supported'
  adding a

  $ echo 'featuresetup-test' >> supported/.hg/requires
  $ cat > $TESTTMP/supported-locally/supportlocally.py <<EOF
  > from mercurial import localrepo, extensions
  > def featuresetup(ui, supported):
  >     for name, module in extensions.extensions(ui):
  >         if __name__ == module.__name__:
  >             # support specific feature locally
  >             supported |= set(['featuresetup-test'])
  >             return
  > def uisetup(ui):
  >     localrepo.localrepository.featuresetupfuncs.add(featuresetup)
  > EOF
  $ cat > supported/.hg/hgrc <<EOF
  > [extensions]
  > # enable extension locally
  > supportlocally = $TESTTMP/supported-locally/supportlocally.py
  > EOF
  $ hg -R supported status

  $ hg init push-dst
  $ hg -R supported push push-dst
  pushing to push-dst
  abort: required features are not supported in the destination: featuresetup-test
  [255]

  $ hg init pull-src
  $ hg -R pull-src pull supported
  pulling from supported
  abort: required features are not supported in the destination: featuresetup-test
  [255]

  $ hg clone supported clone-dst
  abort: repository requires features unknown to this Mercurial: featuresetup-test!
  (see http://mercurial.selenic.com/wiki/MissingRequirement for more information)
  [255]
  $ hg clone --pull supported clone-dst
  abort: required features are not supported in the destination: featuresetup-test
  [255]

  $ cd ..