It is known that the BCJ filter --help text is only
partially translated.

French needs a space before a colon, e.g. "xz : foo error".

This doesn't matter much in practice since it is unlikely
that anyone would have such environment variable names.

Thanks to Wim Lewis.

Reported-by: Diego Elio Pettenò <flameeyes@gentoo.org>
Signed-off-by: Martin Väth <vaeth@mathematik.uni-wuerzburg.de>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Spot candidates by running these commands:
  git ls-files |xargs perl -0777 -n \
    -e 'while (/\b(then?|[iao]n|i[fst]|but|f?or|at|and|[dt]o)\s+\1\b/gims)' \
    -e '{$n=($` =~ tr/\n/\n/ + 1); ($v=$&)=~s/\n/\\n/g; print "$ARGV:$n:$v\n"}'

Thanks to Jim Meyering for the original patch.

It didn't mention the return value that is used if
an error occurs.

Empty Block was created if the input buffer was empty.
Empty Block wastes a few bytes of space, but more importantly
it triggers a bug in XZ Utils 5.0.1 and older when trying
to decompress such a file. 5.0.1 and older consider such
files to be corrupt. I thought that no encoder creates empty
Blocks when releasing 5.0.2 but I was wrong.

This return value was missing from the API comments of
four functions.

The biggest problem was that the integrity check type
wasn't validated, and e.g. lzma_easy_buffer_encode()
would create a corrupt .xz Stream if given an unsupported
Check ID. Luckily applications don't usually try to use
an unsupport Check ID, so this bug is unlikely to cause
many real-world problems.

Passing --disable-decoders to configure broke a few
encoders due to missing #ifdefs in filter_common.c.

Thanks to Jason Gorski for the patch.

It leaks old filter options structures (hundred bytes or so)
every time the lzma_stream is reinitialized. With the xz tool,
this happens when compressing multiple files.

The decoder considered empty LZMA2 streams to be corrupt.
This shouldn't matter much with .xz files, because no encoder
creates empty LZMA2 streams in .xz. This bug is more likely
to cause problems in applications that use raw LZMA2 streams.

Now it uses "grep -q".

Thanks to Gregory Margo.

It didn't work at all. It tried to use the -q option
for grep, but it appended it after "--". This works
around it by redirecting to /dev/null. The downside
is that this can be slower with big files compared
to proper use of "grep -q".

Thanks to Gregory Margo.

struct suffix_pair isn't needed in compresed_name()
so get rid of it there.

Now "xz -S .test foo.test" refuses to compress the
file because it already has the suffix .test. The man
page had it documented this way already.

Thanks to Jakub Bogusz.

xz didn't compress setuid/setgid/sticky files and files
with multiple hard links even with --force. This bug was
introduced in 23ac2c44.

Thanks to Charles Wilson.

Thanks to Cristian Rodríguez for the original patch.