[Json] Re: [Errata Verified] RFC8259 (7383)

[Austin Wright <[e-mail]>]

I believe this errata is unnecessary, RFC 8259 does provide valid ABNF for false/null: Hexadecimal representations of terminal symbols (num-val) are case-insensitive in ABNF. The errata cites the definition of HEXDIG, but it is case insensitive because quoted strings (char-val) are case insensitive.

I also verified this with bap and my own tool.

For comparison, RFC 3986 uses the same HEXDIG production to define percent-encoding, which is also case insensitive: <https://datatracker.ietf.org/doc/html/rfc3986#section-2.1>. And while the vast majority of ABNF prefers uppercase hexadecimal, about a dozen RFCs use lowercase (e.g. RFC 3028, 7489).

Regards,

Austin Wright

> On May 28, 2026, at 11:35, [e-mail] wrote:
> 
> The following errata report has been verified for RFC8259,
> "The JavaScript Object Notation (JSON) Data Interchange Format"
> 
> --------------------------------------
> You may review the report below and at:
> https://errata.rfc-editor.org/eid7383/
> 
> --------------------------------------
> 
> Status: Verified
> Type: Technical
> Reported by: Daniel Tegründe <[e-mail]>
> Date Reported: March 12, 2023, 7 p.m.
> Verified by: Andy Newton (IESG)
> 
> Section 3.  Values says:
> 
> Original Text
> -------------
> false = %x66.61.6c.73.65   ; false
> 
>      null  = %x6e.75.6c.6c      ; null
> 
> Corrected Text
> --------------
> false = %x66.61.6C.73.65   ; false
> 
>      null  = %x6E.75.6C.6C      ; null
> 
> Notes
> -----
> Hex values should be capitalized https://www.rfc-editor.org/rfc/rfc5234#appendix-B.1
> 
> --------------------------------------
> RFC8259 (draft-ietf-jsonbis-rfc7159bis)
> --------------------------------------
> Title               : The JavaScript Object Notation (JSON) Data Interchange Format
> Publication Date    : December 2017
> Author(s)           : T. Bray, Ed.
> Category            : Internet Standard
> Source              : jsonbis (art)
> Stream              : IETF
> 
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