[PATCH v3] Re: git-am: fix maildir support regression: accept email file as patch

[Nicolas Sebrecht <nicolas.s.dev@gmx.fr>]

The 15/07/09, Junio C Hamano wrote:

> I think you did not understand the point of the three liner I sent you.
> 
> 	sed -e '/^$/q' -e '/^[ 	]/d' "$1" |

I'll change it to

 	sed -e '/^$/q' -e '/^[[:blank:]]/d' "$1" |

to conform to reality (and the paragraph 3.4.2 of the RFC 822).

>     The point of this is not to use the silly "we only look at the first
>     three lines" rule.  Instead, it ignores these l1/l2/l3, but grabs all
>     the header lines, but discards second and subsequent physical lines if
>     a logical line was folded.  Which means that the effect of this is to
>     pipe the whole header (again, without worrying about the indented
>     remainder of folded lines) to downsream, which is the grep -v below
> 
>         grep -v -E -e '^[A-Za-z]+(-[A-Za-z]+)*:' >/dev/null ||
>
>     This checks if there is a line that does _NOT_ match the usual
>     e-mail header pattern.  If there is such a line, it means that the
>     file is not an e-mail message.  If there is no such line, we say...

I don't see the reason to have the option -v. It's only related to
what's printed to output and doesn't change the exit status which
tell us if an expression has matched.

This gives:

   grep -E -e '^[A-Za-z]+(-[A-Za-z]+)*:' >/dev/null &&
   patch_format=mbox

> One caveat is that the above logic alone won't catch a random file that
> does not have _any_ e-mail headers in it.  So you might need to do
> something like:
> 
> 	LF='
>         '
> 	case "$l1$LF$l2$LF$l3" in
>         *"$LF$LF"*)
>         	# has a completely empty line in there?
>                 # that means the message has only two headers at most;
>                 # that cannot be an email.
> 		;;

I think we can strip this part. The purpose is to accept what _may_ be a
patch. Any wrong patch or random file will be rejected later.

-- 
Nicolas Sebrecht