git-annex/doc/bugs/problems_with_utf8_names.mdwn
2010-12-28 15:28:23 -04:00

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There are problems with displaying filenames in UTF8 encoding, as shown here:
$ echo $LANG
en_GB.UTF-8
$ git init
$ git annex init test
[...]
$ touch "Umlaut Ü.txt"
$ git annex add Uml*
add Umlaut Ã.txt ok
(Recording state in git...)
$ find -name U\* | hexdump -C
00000000 2e 2f 55 6d 6c 61 75 74 20 c3 9c 2e 74 78 74 0a |./Umlaut ...txt.|
00000010
$ git annex find | hexdump -C
00000000 55 6d 6c 61 75 74 20 c3 83 c2 9c 2e 74 78 74 0a |Umlaut .....txt.|
00000010
$
It looks like the common latin1-to-UTF8 encoding. Functionality other than otuput seems not to be affected.
> Yes, I believe that git-annex is reading filename data from git
> as a stream of char8s, and not decoding unicode in it into logical
> characters.
> Haskell then I guess, tries to unicode encode it when it's output to
> the console.
> This only seems to matter WRT its output to the console; the data
> does not get mangled internally and so it accesses the right files
> under the hood.
>
> I am too new to haskell to really have a handle on how to handle
> unicode and other encodings issues with it. In general, there are three
> valid approaches: --[[Joey]]
>
> 1. Convert all input data to unicode and be unicode clean end-to-end
> internally. Problimatic here since filenames may not necessarily be
> encoded in utf-8 (an archive could have historical filenames using
> varying encodings), and you don't want which files are accessed to
> depend on locale settings.
> 1. Keep input and internal data un-decoded, but decode it when
> outputting a filename (assuming the filename is encoded using the
> user's configured encoding), and allow haskell's output encoding to then
> encode it according to the user's locale configuration.
> 1. Avoid encodings entirely. Mostly what I'm doing now; probably
> could find a way to disable encoding of console output. Then the raw
> filename would be displayed, which should work ok. git-annex does
> not really need to pull apart filenames; they are almost entirely
> opaque blobs. I guess that the `--exclude` option is the exception
> to that, but it is currently not unicode safe anyway.
> One other possible
> issue would be that this could cause problems if git-annex were
> translated.
>
> BTW, for more fun, try unsetting LANG, and then you can see
> stuff like this:
joey@gnu:~/tmp/aa>git annex add ./Üa
add add add add git-annex: <stdout>: commitAndReleaseBuffer: invalid
argument (Invalid or incomplete multibyte or wide character)
> (Add -q to work around this; once it doesn't need to print the filename,
> it can act on it ok!)