Subject: Re: [PATCH] split_ident: parse timestamp from end of line

From: Junio C Hamano <[email-masked]>
Date: Mon, 14 Oct 2013 15:25:29 -0700

Jeff King <[email-masked]> writes:

> You could take this concept further and try to do something clever with
> the email when we notice the extra ">". But I think that is where this
> crosses from "easily and simply covers a class of errors" into "losing
> proposition trying to tweak heuristics around various breakages".

True.

> The only thing that gives me pause here is that parsing from the right
> would close the door to ever adding any new information on the end of an
> ident line. I'd be surprised if that door wasn't already closed by the
> existing parsers, but I feel like the topic might have come up sometime
> in the past year or two (but I can't seem to find anything in the
> archive).

I do not recall any, either.

The approach to parse from the right-end feels like the simplest and
the clearest one to get the piece of information that matters in the
presence of breakages like the ones you mentioned.

> +	/*
> +	 * Look from the end-of-line to find the trailing ">" of the mail
> +	 * address, even though we should already know it as split->mail_end.
> +	 * This can help in cases of broken idents with an extra ">" somewhere
> +	 * in the email address.  Note that we are assuming the timestamp will
> +	 * never have a ">" in it.
> +	 *
> +	 * Note also that this memchr can never return NULL, as we would
> +	 * always find at least the split->mail_end closing bracket.
> +	 */
> +	cp = memrchr(split->mail_end, '>', len - (split->mail_end - line));
> +	for (cp = cp + 1; cp < line + len && isspace(*cp); cp++)
>  		;

"git grep" tells me this is the first use of memrchr(), which,
unlike memchr(), is _GNU_SOURCE-only if I am not mistaken, so we may
need a fallback definition in the compat/ and NEEDS_MEMRCHR in the
Makefile, I think.