view tests/test-i18n.t @ 46607:e9901d01d135

revlog: add a mechanism to verify expected file position before appending

If someone uses `hg debuglocks`, or some non-hg process writes to the .hg
directory without respecting the locks, or if the repo's on a networked
filesystem, it's possible for the revlog code to write out corrupted data.

The form of this corruption can vary depending on what data was written and how
that happened. We are in the "networked filesystem" case (though I've had users
also do this to themselves with the "`hg debuglocks`" scenario), and most often
see this with the changelog. What ends up happening is we produce two items
(let's call them rev1 and rev2) in the .i file that have the same linkrev,
baserev, and offset into the .d file, while the data in the .d file is appended
properly. rev2's compressed_size is accurate for rev2, but when we go to
decompress the data in the .d file, we use the offset that's recorded in the
index file, which is the same as rev1, and attempt to decompress
rev2.compressed_size bytes of rev1's data. This usually does not succeed. :)

When using inline data, this also fails, though I haven't investigated why too
closely. This shows up as a "patch decode" error. I believe what's happening
there is that we're basically ignoring the offset field, getting the data
properly, but since baserev != rev, it thinks this is a delta based on rev
(instead of a full text) and can't actually apply it as such.

For now, I'm going to make this an optional component and default it to entirely
off. I may increase the default severity of this in the future, once I've
enabled it for my users and we gain more experience with it. Luckily, most of my
users have a versioned filesystem and can roll back to before the corruption has
been written, it's just a hassle to do so and not everyone knows how (so it's a
support burden). Users on other filesystems will not have that luxury, and this
can cause them to have a corrupted repository that they are unlikely to know how
to resolve, and they'll see this as a data-loss event. Refusing to create the
corruption is a much better user experience.

This mechanism is not perfect. There may be false-negatives (racy writes that
are not detected). There should not be any false-positives (non-racy writes that
are detected as such). This is not a mechanism that makes putting a repo on a
networked filesystem "safe" or "supported", just *less* likely to cause
corruption.

Differential Revision: https://phab.mercurial-scm.org/D9952

(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