vocab : ignore invalid UTF-8 input in the BPE tokenizer (#11729)

Silently insert U+FFFD(s) (Unicode replacement character) instead until the
next valid codepoint can be found.

This fixes `llama_tokenize` throwing an exception across the C API boundary
or libllama's module boundary (the caller's runtime might be incompatible!)

Returing a proper error code might be desirable, however the signature
of `llama_tokenize` doesn't allow it as all return values already have
existing meaning.
This commit is contained in:
Christian Fillion 2025-02-07 08:55:47 -05:00 committed by GitHub
parent 333820d749
commit 2d219b389e
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@ -618,7 +618,14 @@ std::vector<uint32_t> unicode_cpts_from_utf8(const std::string & utf8) {
result.reserve(utf8.size());
size_t offset = 0;
while (offset < utf8.size()) {
result.push_back(unicode_cpt_from_utf8(utf8, offset));
try {
result.push_back(unicode_cpt_from_utf8(utf8, offset));
}
catch (const std::invalid_argument & /*ex*/) {
// Silently ignore invalid UTF-8 input to avoid leaking the exception beyond llama_tokenize
++offset;
result.emplace_back(0xFFFD); // replacement character
}
}
return result;
}