Re: [RFC 0/1] mailinfo: de-quote quoted-pair in header fields

From: Jeff King <peff@peff.net>
Date: Sep 14, 2016, 19:17 UTC
Message-ID: <20160914191759.5unwaq2eequ4pifr@sigill.intra.peff.net>
In-Reply-To: <xmqqoa3qqsw9.fsf@gitster.mtv.corp.google.com>

On Wed, Sep 14, 2016 at 10:43:18AM -0700, Junio C Hamano wrote:

Show 5 quoted lines

> I think we can go either way and it does not matter all that much if
> "mailinfo" changes its output or the reader of "mailinfo" output
> changes its input--we will either be munging data read from "From:"
> when producing the "Author:" line, or taking the "Author:" output by
> mailinfo and removing the quotes.

Yeah, that was the part I was wondering about in my original response. What is the output of mailinfo _supposed_ to be, and do we consider that at all public (i.e., are there are other tools besides "git am" that build on mailinfo)?

At least "am" already does some quote-stripping, so any de-quoting added in mailinfo is potentially a regression (if we indeed care about keeping the output stable).

But if we are OK with that, it seems to me that mailinfo is the best place to do the de-quoting, because then its output is well-defined: everything after "Author:" up to the newline is the name. Whereas if the cleanup of the value is split across mailinfo and its reader, then it is hard to know which side is responsible for which part. mailinfo handles whitespace unfolding, certainly. What other rfc2822 things does it handle? What are the rules for dequoting its output?

I'll admit I don't care _too_ much. This is a remote corner of the code that I hope never to have to look at. I'm mostly just describing how the problem space makes sense to _me_, and how I would write it if starting from scratch.

-Peff