Reject under-length codes in SedolCheckDigit - #435
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isValid only rejected over-length codes, so a short string with a chance modulus 10 check digit validated. Require the validated seven-character form exactly; the calculate path keeps the base-length handling.
garydgregory
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Thank you @sahvx655-wq , merged 🚀 |
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Aug 26, 2026
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SedolCheckDigit.SEDOL_CHECK_DIGIT.isValidis a publicCheckDigitentry point with no wrapping validator, yet itscalculateModulusoverride only rejects codes longer than the seven-character weight table. A shorter string whose weighted digits happen to sum to a multiple of ten therefore validates:isValid("55"),isValid("550"),isValid("5500")andisValid("0055")all return true, though a SEDOL is defined as exactly seven characters. I traced it back from the weight loop after noticing the base-classisValiddoes no length check of its own, so this one-sided>comparison is the only thing standing between a short input and a false positive.The guard now also requires the validated form (the code passed with its check digit) to be exactly seven characters, while the calculate path still receives the six-character base and so keeps only the over-length check. Holding the length rule inside
calculateModulus, next to the weight table it depends on, keeps the validate and calculate callers consistent without either repeating it. Left as it was, a caller relying onSEDOL_CHECK_DIGITto screen out malformed identifiers would accept a two-character string as a valid security identifier.