view tests/test-check-code.t @ 46667:93e9f448273c

rhg: Add support for automatic fallback to Python

`rhg` is a command-line application that can do a small subset of what
`hg` can. It is written entirely in Rust, which avoids the cost of starting
a Python interpreter and importing many Python modules.
In a script that runs many `hg` commands, this cost can add up.

However making users decide when to use `rhg` instead of `hg` is
not practical as we want the subset of supported functionality
to grow over time.

Instead we introduce "fallback" behavior where, when `rhg` encounters
something (a sub-command, a repository format, …) that is not implemented
in Rust-only, it does nothing but silently start a subprocess of
Python-based `hg` running the same command.
That way `rhg` becomes a drop-in replacement for `hg` that sometimes
goes faster. Whether Python is used should be an implementation detail
not apparent to users (other than through speed).

A new `fallback` value is added to the previously introduced
`rhg.on-unsupported` configuration key. When in this mode, the new
`rhg.fallback-executable` config is determine what command to use
to run a Python-based `hg`.

The previous `rhg.on-unsupported = abort-silent` configuration was designed
to let a wrapper script call `rhg` and then fall back to `hg` based on the
exit code. This is still available, but having fallback behavior built-in
in rhg might be easier for users instead of leaving that script "as an
exercise for the reader".

Using a subprocess like this is not idea, especially when `rhg` is to be
installed in `$PATH` as `hg`, since the other `hg.py` executable needs
to still be available… somewhere. Eventually this could be replaced
by using PyOxidizer to a have a single executable that embeds a Python
interpreter, but only starts it when needed.

Differential Revision: https://phab.mercurial-scm.org/D10093

#require test-repo

  $ . "$TESTDIR/helpers-testrepo.sh"
  $ check_code="$TESTDIR"/../contrib/check-code.py
  $ cd "$TESTDIR"/..

New errors are not allowed. Warnings are strongly discouraged.
(The writing "no-che?k-code" is for not skipping this file when checking.)

  $ testrepohg locate \
  > -X contrib/python-zstandard \
  > -X hgext/fsmonitor/pywatchman \
  > -X mercurial/thirdparty \
  > -X mercurial/pythoncapi_compat.h \
  > | sed 's-\\-/-g' | "$check_code" --warnings --per-file=0 - || false
  Skipping contrib/automation/hgautomation/__init__.py it has no-che?k-code (glob)
  Skipping contrib/automation/hgautomation/aws.py it has no-che?k-code (glob)
  Skipping contrib/automation/hgautomation/cli.py it has no-che?k-code (glob)
  Skipping contrib/automation/hgautomation/linux.py it has no-che?k-code (glob)
  Skipping contrib/automation/hgautomation/pypi.py it has no-che?k-code (glob)
  Skipping contrib/automation/hgautomation/ssh.py it has no-che?k-code (glob)
  Skipping contrib/automation/hgautomation/try_server.py it has no-che?k-code (glob)
  Skipping contrib/automation/hgautomation/windows.py it has no-che?k-code (glob)
  Skipping contrib/automation/hgautomation/winrm.py it has no-che?k-code (glob)
  Skipping contrib/fuzz/FuzzedDataProvider.h it has no-che?k-code (glob)
  Skipping contrib/fuzz/standalone_fuzz_target_runner.cc it has no-che?k-code (glob)
  Skipping contrib/packaging/hgpackaging/cli.py it has no-che?k-code (glob)
  Skipping contrib/packaging/hgpackaging/downloads.py it has no-che?k-code (glob)
  Skipping contrib/packaging/hgpackaging/inno.py it has no-che?k-code (glob)
  Skipping contrib/packaging/hgpackaging/py2exe.py it has no-che?k-code (glob)
  Skipping contrib/packaging/hgpackaging/pyoxidizer.py it has no-che?k-code (glob)
  Skipping contrib/packaging/hgpackaging/util.py it has no-che?k-code (glob)
  Skipping contrib/packaging/hgpackaging/wix.py it has no-che?k-code (glob)
  Skipping i18n/polib.py it has no-che?k-code (glob)
  Skipping mercurial/statprof.py it has no-che?k-code (glob)
  Skipping tests/badserverext.py it has no-che?k-code (glob)

@commands in debugcommands.py should be in alphabetical order.

  >>> import re
  >>> commands = []
  >>> with open('mercurial/debugcommands.py', 'rb') as fh:
  ...     for line in fh:
  ...         m = re.match(br"^@command\('([a-z]+)", line)
  ...         if m:
  ...             commands.append(m.group(1))
  >>> scommands = list(sorted(commands))
  >>> for i, command in enumerate(scommands):
  ...     if command != commands[i]:
  ...         print('commands in debugcommands.py not sorted; first differing '
  ...               'command is %s; expected %s' % (commands[i], command))
  ...         break

Prevent adding new files in the root directory accidentally.

  $ testrepohg files 'glob:*'
  .arcconfig
  .clang-format
  .editorconfig
  .hgignore
  .hgsigs
  .hgtags
  .jshintrc
  CONTRIBUTING
  CONTRIBUTORS
  COPYING
  Makefile
  README.rst
  black.toml
  hg
  hgeditor
  hgweb.cgi
  rustfmt.toml
  setup.py

Prevent adding modules which could be shadowed by ancient .so/.dylib.

  $ testrepohg files \
  > mercurial/base85.py \
  > mercurial/bdiff.py \
  > mercurial/diffhelpers.py \
  > mercurial/mpatch.py \
  > mercurial/osutil.py \
  > mercurial/parsers.py \
  > mercurial/zstd.py
  [1]

Keep python3 tests sorted:
  $ sort < contrib/python3-whitelist > $TESTTMP/py3sorted
  $ cmp contrib/python3-whitelist $TESTTMP/py3sorted || echo 'Please sort passing tests!'

Keep Windows line endings in check

  $ testrepohg files 'set:eol(dos)'
  contrib/win32/hg.bat
  contrib/win32/mercurial.ini