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path: root/t/t0028-working-tree-encoding.sh
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2019-01-31Support working-tree-encoding "UTF-16LE-BOM"Libravatar Torsten Bögershausen1-1/+11
Users who want UTF-16 files in the working tree set the .gitattributes like this: test.txt working-tree-encoding=UTF-16 The unicode standard itself defines 3 allowed ways how to encode UTF-16. The following 3 versions convert all back to 'g' 'i' 't' in UTF-8: a) UTF-16, without BOM, big endian: $ printf "\000g\000i\000t" | iconv -f UTF-16 -t UTF-8 | od -c 0000000 g i t b) UTF-16, with BOM, little endian: $ printf "\377\376g\000i\000t\000" | iconv -f UTF-16 -t UTF-8 | od -c 0000000 g i t c) UTF-16, with BOM, big endian: $ printf "\376\377\000g\000i\000t" | iconv -f UTF-16 -t UTF-8 | od -c 0000000 g i t Git uses libiconv to convert from UTF-8 in the index into ITF-16 in the working tree. After a checkout, the resulting file has a BOM and is encoded in "UTF-16", in the version (c) above. This is what iconv generates, more details follow below. iconv (and libiconv) can generate UTF-16, UTF-16LE or UTF-16BE: d) UTF-16 $ printf 'git' | iconv -f UTF-8 -t UTF-16 | od -c 0000000 376 377 \0 g \0 i \0 t e) UTF-16LE $ printf 'git' | iconv -f UTF-8 -t UTF-16LE | od -c 0000000 g \0 i \0 t \0 f) UTF-16BE $ printf 'git' | iconv -f UTF-8 -t UTF-16BE | od -c 0000000 \0 g \0 i \0 t There is no way to generate version (b) from above in a Git working tree, but that is what some applications need. (All fully unicode aware applications should be able to read all 3 variants, but in practise we are not there yet). When producing UTF-16 as an output, iconv generates the big endian version with a BOM. (big endian is probably chosen for historical reasons). iconv can produce UTF-16 files with little endianess by using "UTF-16LE" as encoding, and that file does not have a BOM. Not all users (especially under Windows) are happy with this. Some tools are not fully unicode aware and can only handle version (b). Today there is no way to produce version (b) with iconv (or libiconv). Looking into the history of iconv, it seems as if version (c) will be used in all future iconv versions (for compatibility reasons). Solve this dilemma and introduce a Git-specific "UTF-16LE-BOM". libiconv can not handle the encoding, so Git pick it up, handles the BOM and uses libiconv to convert the rest of the stream. (UTF-16BE-BOM is added for consistency) Rported-by: Adrián Gimeno Balaguer <adrigibal@gmail.com> Signed-off-by: Torsten Bögershausen <tboegi@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-29tests: fix non-portable iconv invocationLibravatar Ævar Arnfjörð Bjarmason1-1/+5
The iconv that comes with a FreeBSD 11.2-RELEASE-p2 box I have access to doesn't support the SHIFT-JIS encoding. Guard a test added in e92d62253 ("convert: add round trip check based on 'core.checkRoundtripEncoding'", 2018-04-15) first released with Git v2.18.0 with a prerequisite that checks for its availability. The iconv command is in POSIX, and we have numerous tests unconditionally relying on its ability to convert ASCII, UTF-8 and UTF-16, but unconditionally relying on the presence of more obscure encodings isn't portable. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-16convert: add round trip check based on 'core.checkRoundtripEncoding'Libravatar Lars Schneider1-0/+39
UTF supports lossless conversion round tripping and conversions between UTF and other encodings are mostly round trip safe as Unicode aims to be a superset of all other character encodings. However, certain encodings (e.g. SHIFT-JIS) are known to have round trip issues [1]. Add 'core.checkRoundtripEncoding', which contains a comma separated list of encodings, to define for what encodings Git should check the conversion round trip if they are used in the 'working-tree-encoding' attribute. Set SHIFT-JIS as default value for 'core.checkRoundtripEncoding'. [1] https://support.microsoft.com/en-us/help/170559/prb-conversion-problem-between-shift-jis-and-unicode Signed-off-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-16convert: add tracing for 'working-tree-encoding' attributeLibravatar Lars Schneider1-0/+2
Add the GIT_TRACE_WORKING_TREE_ENCODING environment variable to enable tracing for content that is reencoded with the 'working-tree-encoding' attribute. This is useful to debug encoding issues. Signed-off-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-16convert: check for detectable errors in UTF encodingsLibravatar Lars Schneider1-0/+62
Check that new content is valid with respect to the user defined 'working-tree-encoding' attribute. Signed-off-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-16convert: add 'working-tree-encoding' attributeLibravatar Lars Schneider1-0/+142
Git recognizes files encoded with ASCII or one of its supersets (e.g. UTF-8 or ISO-8859-1) as text files. All other encodings are usually interpreted as binary and consequently built-in Git text processing tools (e.g. 'git diff') as well as most Git web front ends do not visualize the content. Add an attribute to tell Git what encoding the user has defined for a given file. If the content is added to the index, then Git reencodes the content to a canonical UTF-8 representation. On checkout Git will reverse this operation. Signed-off-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>