Re: [RFC PATCH v1 1/1] docs: add the new commit-msg tags 'Reported:' and 'Reviewed:'

[Jani Nikula <jani.nikula@intel.com>]

On Sat, 27 Nov 2021, Junio C Hamano <gitster@pobox.com> wrote:
> Eric Wong <e@80x24.org> writes:
>
>> Thorsten Leemhuis <linux@leemhuis.info> wrote:
>>> Just to be sure I'll do what you expect to be done: I assume you want to see
>>> it changed like this?
>>> 
>>> -	perl -pi -e 's|^Message-Id:\s*<?([^>]+)>?$|Link: https://lore.kernel.org/r/$1|g;' "$1"
>> ...
>> The entire match should be case-insensitive[1], so I'd add `i'
>> at the end:
>>
>> 	perl -pi -e 's|^Message-ID:\s*<?([^>]+)>?$|Link: https://lore.kernel.org/r/$1|gi;' "$1"
>>
>> Fwiw, every mail and HTTP/1.x header parser I've looked at works
>> case-insensitively.  Also, I'm not sure if `g' is needed, actually...
>
> It is left anchored with "^" so it would be hard to match more than
> once on the same line ;-)
>
> I agree that it is the right solution to make the whole thing
> case-insensitive by adding 'i' at the end.
>
> FWIW, the RFC first says this:
>
>     1.2.2. Syntactic notation
>
>        This standard uses the Augmented Backus-Naur Form (ABNF) notation
>        specified in [RFC2234] for the formal definitions of the syntax of
>        messages.  Characters will be specified either by a decimal value
>        (e.g., the value %d65 for uppercase A and %d97 for lowercase A) or by
>        a case-insensitive literal value enclosed in quotation marks (e.g.,
>        "A" for either uppercase or lowercase A).
>
> and then goes on to define how message-id should look like.
>
>     3.6.4. Identification fields
>
>     message-id      =       "Message-ID:" msg-id CRLF
>
>
> But if you go the "add /i at the end" route, you do not have to
> upcase "d" to "D" and that may reduce the patch noise (it only
> matters if the patch viewer highlights letter-by-letter changes for
> your recipients).

From the RFC nitpicking department, msg-id is allowed to contain CFWS
(comments and folding white space) outside the angle brackets, which
means you could have RFC compliant Message-ID header field:

Message-ID: 
  <message-id@example.com>

or

Message-ID: (comment) 
  <message-id@example.com>

or even worse, really.

The moral of the story is that you should always offload the header
parsing to some tool or library designed to do that.


BR,
Jani.


-- 
Jani Nikula, Intel Open Source Graphics Center