tests/test-check-py3-compat.t

tests: add test for Python 3 compatibility

Python 3 is inevitable. There have been incremental movements towards
converting the code base to be Python 3 compatible. Unfortunately, we
don't have any tests that look for Python 3 compatibility. This patch
changes that.

We introduce a check-py3-compat.py script whose role is to verify
Python 3 compatibility of the files passed in. We add a test that
calls this script with all .py files from the source checkout.

The script currently only verifies that absolute_import and
print_function are used. These are the low hanging fruits for Python
compatbility. Over time, we can include more checks, including
verifying we're able to load each Python file with Python 3. You
have to start somewhere.

Accepting this patch means that all new .py files must have
absolute_import and print_function (if "print" is used) to avoid
a new warning about Python 3 incompatibility. We've already
converted several files to use absolute_import and print_function
is in the same boat, so I don't think this is such a radical
proposition.

#require test-repo

  $ cd "$TESTDIR"/..

  $ hg files 'set:(**.py)' | xargs python contrib/check-py3-compat.py
  contrib/casesmash.py not using absolute_import
  contrib/check-code.py not using absolute_import
  contrib/check-code.py requires print_function
  contrib/check-config.py not using absolute_import
  contrib/check-config.py requires print_function
  contrib/debugcmdserver.py not using absolute_import
  contrib/debugcmdserver.py requires print_function
  contrib/debugshell.py not using absolute_import
  contrib/fixpax.py not using absolute_import
  contrib/fixpax.py requires print_function
  contrib/hgclient.py not using absolute_import
  contrib/hgclient.py requires print_function
  contrib/hgfixes/__init__.py not using absolute_import
  contrib/hgfixes/fix_bytes.py not using absolute_import
  contrib/hgfixes/fix_bytesmod.py not using absolute_import
  contrib/hgfixes/fix_leftover_imports.py not using absolute_import
  contrib/import-checker.py not using absolute_import
  contrib/import-checker.py requires print_function
  contrib/memory.py not using absolute_import
  contrib/perf.py not using absolute_import
  contrib/python-hook-examples.py not using absolute_import
  contrib/revsetbenchmarks.py not using absolute_import
  contrib/revsetbenchmarks.py requires print_function
  contrib/showstack.py not using absolute_import
  contrib/synthrepo.py not using absolute_import
  contrib/win32/hgwebdir_wsgi.py not using absolute_import
  doc/check-seclevel.py not using absolute_import
  doc/gendoc.py not using absolute_import
  doc/hgmanpage.py not using absolute_import
  hgext/__init__.py not using absolute_import
  hgext/acl.py not using absolute_import
  hgext/blackbox.py not using absolute_import
  hgext/bugzilla.py not using absolute_import
  hgext/censor.py not using absolute_import
  hgext/children.py not using absolute_import
  hgext/churn.py not using absolute_import
  hgext/clonebundles.py not using absolute_import
  hgext/color.py not using absolute_import
  hgext/convert/__init__.py not using absolute_import
  hgext/convert/bzr.py not using absolute_import
  hgext/convert/common.py not using absolute_import
  hgext/convert/convcmd.py not using absolute_import
  hgext/convert/cvs.py not using absolute_import
  hgext/convert/cvsps.py not using absolute_import
  hgext/convert/darcs.py not using absolute_import
  hgext/convert/filemap.py not using absolute_import
  hgext/convert/git.py not using absolute_import
  hgext/convert/gnuarch.py not using absolute_import
  hgext/convert/hg.py not using absolute_import
  hgext/convert/monotone.py not using absolute_import
  hgext/convert/p4.py not using absolute_import
  hgext/convert/subversion.py not using absolute_import
  hgext/convert/transport.py not using absolute_import
  hgext/eol.py not using absolute_import
  hgext/extdiff.py not using absolute_import
  hgext/factotum.py not using absolute_import
  hgext/fetch.py not using absolute_import
  hgext/gpg.py not using absolute_import
  hgext/graphlog.py not using absolute_import
  hgext/hgcia.py not using absolute_import
  hgext/hgk.py not using absolute_import
  hgext/highlight/__init__.py not using absolute_import
  hgext/highlight/highlight.py not using absolute_import
  hgext/histedit.py not using absolute_import
  hgext/keyword.py not using absolute_import
  hgext/largefiles/__init__.py not using absolute_import
  hgext/largefiles/basestore.py not using absolute_import
  hgext/largefiles/lfcommands.py not using absolute_import
  hgext/largefiles/lfutil.py not using absolute_import
  hgext/largefiles/localstore.py not using absolute_import
  hgext/largefiles/overrides.py not using absolute_import
  hgext/largefiles/proto.py not using absolute_import
  hgext/largefiles/remotestore.py not using absolute_import
  hgext/largefiles/reposetup.py not using absolute_import
  hgext/largefiles/uisetup.py not using absolute_import
  hgext/largefiles/wirestore.py not using absolute_import
  hgext/mq.py not using absolute_import
  hgext/notify.py not using absolute_import
  hgext/pager.py not using absolute_import
  hgext/patchbomb.py not using absolute_import
  hgext/purge.py not using absolute_import
  hgext/rebase.py not using absolute_import
  hgext/record.py not using absolute_import
  hgext/relink.py not using absolute_import
  hgext/schemes.py not using absolute_import
  hgext/share.py not using absolute_import
  hgext/shelve.py not using absolute_import
  hgext/strip.py not using absolute_import
  hgext/transplant.py not using absolute_import
  hgext/win32mbcs.py not using absolute_import
  hgext/win32text.py not using absolute_import
  hgext/zeroconf/Zeroconf.py not using absolute_import
  hgext/zeroconf/Zeroconf.py requires print_function
  hgext/zeroconf/__init__.py not using absolute_import
  i18n/check-translation.py not using absolute_import
  i18n/polib.py not using absolute_import
  mercurial/byterange.py not using absolute_import
  mercurial/cmdutil.py not using absolute_import
  mercurial/commands.py not using absolute_import
  mercurial/commandserver.py not using absolute_import
  mercurial/context.py not using absolute_import
  mercurial/destutil.py not using absolute_import
  mercurial/dirstate.py not using absolute_import
  mercurial/dispatch.py requires print_function
  mercurial/encoding.py not using absolute_import
  mercurial/exchange.py not using absolute_import
  mercurial/help.py not using absolute_import
  mercurial/httpclient/__init__.py not using absolute_import
  mercurial/httpclient/_readers.py not using absolute_import
  mercurial/httpclient/socketutil.py not using absolute_import
  mercurial/httpconnection.py not using absolute_import
  mercurial/keepalive.py not using absolute_import
  mercurial/keepalive.py requires print_function
  mercurial/localrepo.py not using absolute_import
  mercurial/lsprof.py requires print_function
  mercurial/lsprofcalltree.py not using absolute_import
  mercurial/lsprofcalltree.py requires print_function
  mercurial/mail.py requires print_function
  mercurial/manifest.py not using absolute_import
  mercurial/mdiff.py not using absolute_import
  mercurial/obsolete.py not using absolute_import
  mercurial/patch.py not using absolute_import
  mercurial/pure/__init__.py not using absolute_import
  mercurial/pure/base85.py not using absolute_import
  mercurial/pure/bdiff.py not using absolute_import
  mercurial/pure/diffhelpers.py not using absolute_import
  mercurial/pure/mpatch.py not using absolute_import
  mercurial/pure/osutil.py not using absolute_import
  mercurial/pure/parsers.py not using absolute_import
  mercurial/pvec.py not using absolute_import
  mercurial/py3kcompat.py not using absolute_import
  mercurial/revlog.py not using absolute_import
  mercurial/scmposix.py not using absolute_import
  mercurial/scmutil.py not using absolute_import
  mercurial/scmwindows.py not using absolute_import
  mercurial/similar.py not using absolute_import
  mercurial/store.py not using absolute_import
  mercurial/util.py not using absolute_import
  mercurial/windows.py not using absolute_import
  setup.py not using absolute_import
  tests/autodiff.py not using absolute_import
  tests/dumbhttp.py not using absolute_import
  tests/fakedirstatewritetime.py not using absolute_import
  tests/fakepatchtime.py not using absolute_import
  tests/filterpyflakes.py not using absolute_import
  tests/filterpyflakes.py requires print_function
  tests/generate-working-copy-states.py not using absolute_import
  tests/generate-working-copy-states.py requires print_function
  tests/get-with-headers.py not using absolute_import
  tests/get-with-headers.py requires print_function
  tests/heredoctest.py not using absolute_import
  tests/heredoctest.py requires print_function
  tests/hghave.py not using absolute_import
  tests/hgweberror.py not using absolute_import
  tests/hypothesishelpers.py not using absolute_import
  tests/hypothesishelpers.py requires print_function
  tests/killdaemons.py not using absolute_import
  tests/md5sum.py not using absolute_import
  tests/mockblackbox.py not using absolute_import
  tests/printenv.py not using absolute_import
  tests/readlink.py not using absolute_import
  tests/readlink.py requires print_function
  tests/revlog-formatv0.py not using absolute_import
  tests/run-tests.py not using absolute_import
  tests/seq.py not using absolute_import
  tests/seq.py requires print_function
  tests/silenttestrunner.py not using absolute_import
  tests/silenttestrunner.py requires print_function
  tests/sitecustomize.py not using absolute_import
  tests/svn-safe-append.py not using absolute_import
  tests/svnxml.py not using absolute_import
  tests/test-ancestor.py not using absolute_import
  tests/test-ancestor.py requires print_function
  tests/test-atomictempfile.py not using absolute_import
  tests/test-batching.py not using absolute_import
  tests/test-batching.py requires print_function
  tests/test-bdiff.py not using absolute_import
  tests/test-bdiff.py requires print_function
  tests/test-context.py not using absolute_import
  tests/test-context.py requires print_function
  tests/test-demandimport.py not using absolute_import
  tests/test-demandimport.py requires print_function
  tests/test-dispatch.py not using absolute_import
  tests/test-dispatch.py requires print_function
  tests/test-doctest.py not using absolute_import
  tests/test-duplicateoptions.py not using absolute_import
  tests/test-duplicateoptions.py requires print_function
  tests/test-filecache.py not using absolute_import
  tests/test-filecache.py requires print_function
  tests/test-filelog.py not using absolute_import
  tests/test-filelog.py requires print_function
  tests/test-hg-parseurl.py not using absolute_import
  tests/test-hg-parseurl.py requires print_function
  tests/test-hgweb-auth.py not using absolute_import
  tests/test-hgweb-auth.py requires print_function
  tests/test-hgwebdir-paths.py not using absolute_import
  tests/test-hybridencode.py not using absolute_import
  tests/test-hybridencode.py requires print_function
  tests/test-lrucachedict.py not using absolute_import
  tests/test-lrucachedict.py requires print_function
  tests/test-manifest.py not using absolute_import
  tests/test-minirst.py not using absolute_import
  tests/test-minirst.py requires print_function
  tests/test-parseindex2.py not using absolute_import
  tests/test-parseindex2.py requires print_function
  tests/test-pathencode.py not using absolute_import
  tests/test-pathencode.py requires print_function
  tests/test-propertycache.py not using absolute_import
  tests/test-propertycache.py requires print_function
  tests/test-revlog-ancestry.py not using absolute_import
  tests/test-revlog-ancestry.py requires print_function
  tests/test-run-tests.py not using absolute_import
  tests/test-simplemerge.py not using absolute_import
  tests/test-status-inprocess.py not using absolute_import
  tests/test-status-inprocess.py requires print_function
  tests/test-symlink-os-yes-fs-no.py not using absolute_import
  tests/test-trusted.py not using absolute_import
  tests/test-trusted.py requires print_function
  tests/test-ui-color.py not using absolute_import
  tests/test-ui-color.py requires print_function
  tests/test-ui-config.py not using absolute_import
  tests/test-ui-config.py requires print_function
  tests/test-ui-verbosity.py not using absolute_import
  tests/test-ui-verbosity.py requires print_function
  tests/test-url.py not using absolute_import
  tests/test-url.py requires print_function
  tests/test-walkrepo.py not using absolute_import
  tests/test-walkrepo.py requires print_function
  tests/test-wireproto.py not using absolute_import
  tests/test-wireproto.py requires print_function
  tests/tinyproxy.py not using absolute_import
  tests/tinyproxy.py requires print_function