(protobuf) Fix writeString(char[],int,int) writing enum values twice

[pjfanning]

The EnumLookup sizing fix that was originally in this PR has been split out into #773.

ProtobufGenerator.writeString(char[],int,int) writes enum values twice

if (_currField.wireType != WireType.LENGTH_PREFIXED) {
    _writeEnum(new String(text, offset, clen));
    // no return -- falls through
}

The String overload returns after _writeEnum(); the char[] one did not, so it emitted the enum index and then fell through and emitted the same value again as a length-prefixed String. Writing "WEB" to an enum field produced 7 bytes instead of 2, i.e. corrupt output.

Pre-dates the 2.x -> 3.x rename and is present on 2.21 too; targeting 3.x for now, happy to redo against 2.21 and merge forward if you prefer.

Test

WriteEnumAsCharArrayTest — the char[] and String overloads must produce identical bytes for an enum-valued field, and the result must round-trip. Confirmed it fails with expected: <2> but was: <7> if the return is removed again.

Full protobuf module test suite passes.

🤖 Generated with Claude Code

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