view tests/test-i18n.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

(Translations are optional)

#if gettext no-outer-repo

Test that translations are compiled and installed correctly.

Default encoding in tests is "ascii" and the translation is encoded
using the "replace" error handler:

  $ LANGUAGE=pt_BR hg tip
  abortado: n?o foi encontrado um reposit?rio em '$TESTTMP' (.hg n?o encontrado)
  [10]

Using a more accommodating encoding:

  $ HGENCODING=UTF-8 LANGUAGE=pt_BR hg tip
  abortado: n\xc3\xa3o foi encontrado um reposit\xc3\xb3rio em '$TESTTMP' (.hg n\xc3\xa3o encontrado) (esc)
  [10]

Different encoding:

  $ HGENCODING=Latin-1 LANGUAGE=pt_BR hg tip
  abortado: n\xe3o foi encontrado um reposit\xf3rio em '$TESTTMP' (.hg n\xe3o encontrado) (esc)
  [10]

#endif

#if gettext

Test keyword search in translated help text:

  $ HGENCODING=UTF-8 LANGUAGE=de hg help -k Aktualisiert
  Themen:
  
   subrepos Unterarchive
  
  Befehle:
  
   pull   Ruft \xc3\x84nderungen von der angegebenen Quelle ab (esc)
   update Aktualisiert das Arbeitsverzeichnis (oder wechselt die Version)

#endif

Check Mercurial specific translation problems in each *.po files, and
tool itself by doctest

  $ cd "$TESTDIR"/../i18n
  $ "$PYTHON" check-translation.py *.po
  $ "$PYTHON" check-translation.py --doctest
  $ cd $TESTTMP

#if gettext

Check i18n cache isn't reused after encoding change:

  $ cat > $TESTTMP/encodingchange.py << EOF
  > from mercurial.i18n import _
  > from mercurial import encoding, registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'encodingchange', norepo=True)
  > def encodingchange(ui):
  >     for encode in (b'ascii', b'UTF-8', b'ascii', b'UTF-8'):
  >         encoding.encoding = encode
  >         ui.write(b'%s\n' % _(b'(EXPERIMENTAL)'))
  > EOF

  $ LANGUAGE=ja hg --config extensions.encodingchange=$TESTTMP/encodingchange.py encodingchange
  (?????)
  (\xe5\xae\x9f\xe9\xa8\x93\xe7\x9a\x84\xe5\xae\x9f\xe8\xa3\x85) (esc)
  (?????)
  (\xe5\xae\x9f\xe9\xa8\x93\xe7\x9a\x84\xe5\xae\x9f\xe8\xa3\x85) (esc)

#endif