From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH 2/2] update-hook-example: optionally allow
 non-fast-forward
Date: Wed, 25 Jun 2008 13:04:56 -0700
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To: Dmitry Potapov <dpotapov@gmail.com>
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In-Reply-To: <1214382416-6687-2-git-send-email-dpotapov@gmail.com> (Dmitry
 Potapov's message of "Wed, 25 Jun 2008 12:26:56 +0400")
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Dmitry Potapov <dpotapov@gmail.com> writes:

> Sometimes it is desirable to have non-fast-forward branches in a
> shared repository. A typical example of that is the 'pu' branch.
> This patch extends the format of allowed-users and allow-groups
> files by using the '+' sign at the beginning as the mark that
> non-fast-forward pushes are permitted to the branch.

Thanks.  1/2 queued for 'maint' (as it was an obvious fix) to be included
in 1.5.6.1, but not this one that is a feature enhancement even though it
is in docs.

> Signed-off-by: Dmitry Potapov <dpotapov@gmail.com>

>    rc=$(cat $allowed_users_file | grep -v '^#' | grep -v '^$' |
>      while read head_pattern user_patterns; do
> -      matchlen=$(expr "$1" : "$head_pattern")
> -      if [ "$matchlen" == "${#1}" ]; then
> +      matchlen=$(expr "$1" : "${head_pattern#+}")
> +      allow_noff=$(expr substr "$head_pattern" 1 1)
> +      if [ "$matchlen" = "${#1}" -a \( -z "$noff" -o "$allow_noff" = '+' \) ]; then

"expr substr"?  Please don't.

    cf. http://www.opengroup.org/onlinepubs/000095399/utilities/expr.html

I'd probably write this part like so:

	... pipe ... |
	while read heads users
        do
        	# does this rule apply to us?
        	head_pattern=${heads#+}
                matchlen=$(expr "$1" : "$head_pattern")
                test "$matchlen" = ${#1} || continue

                # if non-ff, $heads must be with the '+' prefix
                test -n "$noff" &&
                test "z$head_pattern" = "z$heads" && continue

                ... Ok this is good.