maxlength is Unicode not bytesWe found out that the validation of field length is in Unicode code points. This is consistent with what Go does for len operator (thank God, so many other languages get this wrong, including Python, JavaScript/Typescript, Java, C/C++ and others). So long at the type is a string and not []byte slice Go does the right thing.
It’s worth mentioning that a regular expression checking for length would always fail here because the length of a span is always in bytes and not Unicode, unless a second match were done just using the newer \P{} and \p{} syntax for Unicode.
The “maxlength” keyword in JSON Schema specifies the maximum length of a string value. It is defined in terms of UTF-16 code units, not in terms of Unicode code points or bytes. Each Unicode code point can be represented by one or two UTF-16 code units. Therefore, the “maxlength” keyword reflects the maximum length of a string in terms of UTF-16 code units.