Detect and fix KOI8-R mojibake (fixes #231) - #234
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The example in rspeer#231 is reported as CP437/CP866, but it is KOI8-R: in that encoding 0xD0 is 'п' and 0xD1 is 'я', the two lead bytes of Cyrillic in UTF-8, and 0x95/0x81 are '∙'/'│'. No other Cyrillic codepage round-trips it -- cp866, koi8-u, iso-8859-5 and mac-cyrillic all fail to encode it. Two changes are needed, and neither one alone is enough: - add koi8-r to CHARMAP_ENCODINGS, so the text can be re-encoded; - add lower_common/upper_common to the rule that pairs a character with a box-drawing character, so that is_bad() fires. KOI8-R mojibake of Cyrillic puts a Cyrillic letter immediately before a box-drawing character, and no existing alternative covers that pair. Adding koi8-r on its own leaves the example unchanged, because the badness heuristic never flags it.
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Fixes#231.
The example in the issue is reported as CP437/CP866, but I'm fairly sure it's KOI8-R. In KOI8-R,
0xD0isпand0xD1isя— the two lead bytes of Cyrillic in UTF-8 — and0x95and0x81are∙and│. That's why the mojibake comes out as Cyrillic letters interleaved with box-drawing characters.I tried the codepages the reporter suggested and the neighbouring Cyrillic ones too:
cp866,koi8-u,iso-8859-5andmac-cyrillicall fail to encode the text, so KOI8-R is the only one that round-trips it.Two changes are needed, and neither one is enough on its own:
koi8-rinCHARMAP_ENCODINGS, so the text can be re-encoded at all.lower_commonandupper_commonin the badness alternative that pairs a character with a box-drawing character. KOI8-R mojibake of Cyrillic puts a Cyrillic letter immediately before a box-drawing character, and no existing alternative covers that pair, sois_bad()never fires.If you apply only the first one, the example still comes back unchanged. That took me a while to work out, so I mention it in case someone tries the shorter patch.
I added the example to
in-the-wild.json. The suite goes from 351 to 353 passing with the same 10 xfails, and the negative cases are untouched.