$ hg init t

  $ cd t

  $ echo a > a

  $ hg add a

  $ hg commit -m test

  $ rm .hg/requires

  $ hg tip

  abort: unknown version (65535) in revlog 00changelog

  [50]

  $ echo indoor-pool > .hg/requires

  $ hg tip

  abort: repository requires features unknown to this Mercurial: indoor-pool

  (see https://mercurial-scm.org/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 https://mercurial-scm.org/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 __future__ import absolute_import

  > from mercurial import extensions, localrepo

  > def featuresetup(ui, supported):

  >     for name, module in extensions.extensions(ui):

  >         if __name__ == module.__name__:

  >             # support specific feature locally

  >             supported |= {b'featuresetup-test'}

  >             return

  > def uisetup(ui):

  >     localrepo.featuresetupfuncs.add(featuresetup)

  > EOF

  $ cat > supported/.hg/hgrc <<EOF

  > [extensions]

  > # enable extension locally

  > supportlocally = $TESTTMP/supported-locally/supportlocally.py

  > EOF

  $ hg -R supported debugrequirements

  dotencode

  dirstate-v2 (dirstate-v2 !)

  featuresetup-test

  fncache

  generaldelta

  persistent-nodemap (rust !)

  revlog-compression-zstd (zstd !)

  revlogv1

  share-safe

  sparserevlog

  store

  $ 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 https://mercurial-scm.org/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 ..