Re: [PATCHv2 1/2] submodule: preserve all arguments exactly when recursing

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Nov 3, 2010, 05:28 UTC
Message-ID: <20101103052837.GB10631@burratino>
In-Reply-To: <1288760740-10075-1-git-send-email-kevin@sb.org>

Kevin Ballard wrote:

Show 15 quoted lines

> When performing a recursive status or update, any argments with whitespace
> would be split along that whitespace when passed to the recursive invocation
> of the update or status command.
> 
> This is caused by the special handling that sh provides to the $@ variable.
> Status and update stored "$@" into a separate variable, and passed that
> variable to the recursive invocation. Unfortunately, the special handling
> afforded to $@ isn't given to this new variable, and word-breaking occurs
> along whitespace boundaries.
> 
> We can use $(git rev-parse --sq-quote "$@") to produce a string containing
> a quoted version of all given args, suitable for passing to eval. We then
> recurse using something like `eval cmd_status "$orig_args"` instead of the
> former `cmd_status $orig_args`. This preserves all arguments exactly as
> given to the initial invocation of the command.

Probably it is because it is late hear, but I find myself intimidated by the block of explanatory text. Maybe an example like

	Environment variables only hold strings, not lists of parameters,
	so $orig_args after

		orig_args="$@"

	fails to remember where each parameter starts and ends, if
	some include whitespace.  So

		git submodule update \
			--reference='/var/lib/common objects.git' \
			--recursive

	becomes

		git submodule update --reference=/var/lib/common \
			objects.git --recursive

	in the inner repositories.  Use "git rev-parse --sq-quote" to
	save parameters in quoted form ready for evaluation by the
	shell, avoiding this problem.

would be simpler?

Show 8 quoted lines

> --- a/git-submodule.sh
> +++ b/git-submodule.sh
> @@ -374,7 +374,7 @@ cmd_init()
>  cmd_update()
>  {
>  	# parse $args after "submodule ... update".
> -	orig_args="$@"
> +	orig_args="$(git rev-parse --sq-quote "$@")"

No quotes are needed around the RHS to an assignment like this.

Anyway,
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

Thanks.