From: Jakub Narebski <jnareb@gmail.com>
Date: Tue, 07 Apr 2009 12:01:37 GMT
Subject: Re: [PATCH] perl: add new module Git::Config for cached 'git config' access
Message-ID: <m3prfo1xh6.fsf@localhost.localdomain>
In-Reply-To: <1239058276.31863.19.camel@maia.lan>

Sam Vilain <sam.vilain@catalyst.net.nz> writes:

> On Mon, 2009-04-06 at 11:29 +0200, Frank Lichtenheld wrote:
> > On Mon, Apr 06, 2009 at 11:46:15AM +1200, Sam Vilain wrote:

> > > +	my ($fh, $c) = $git->command_output_pipe(
> > > +		'config', ( $which ? ("--$which") : () ),
> > > +		'--list',
> > > +	       );
> >
> > Any reason why you don't use --null here? The output of --list
> > without --null is not reliably parsable, since people can put
> > newlines in values.
> 
> No particularly good reason :-)
> 
> Subject: [PATCH] perl: make Git::Config use --null
> 
> Use the form of 'git-config' designed for parsing by modules like
> this for safety with values containing embedded line feeds.
> 
> Signed-off-by: Sam Vilain <sam.vilain@catalyst.net.nz>

> diff --git a/perl/Git/Config.pm b/perl/Git/Config.pm
> index a0a6a41..a35d9f3 100644
> --- a/perl/Git/Config.pm
> +++ b/perl/Git/Config.pm
> @@ -179,12 +179,14 @@ sub read {
>  
>  	my ($fh, $c) = $git->command_output_pipe(
>  		'config', ( $which ? ("--$which") : () ),
> -		'--list',
> +		 '--null', '--list',
>  	       );
>  	my $read_state = {};
>  
> +	local($/)="\0";
>  	while (<$fh>) {
> -		my ($item, $value) = m{(.*?)=(.*)};
> +		my ($item, $value) = m{(.*?)\n((?s:.*))\0}
> +			or die "failed to parse it; \$_='$_'";
>  		my $sl = \( $read_state->{$item} );
>  		if (!defined $$sl) {
>  			$$sl = $value;

Errr... wouldn't it be better to simply use 

+		my ($item, $value) = split("\n", $_, 2)

here? Have you tested Git::Config with a "null" value, i.e. something
like

    [section]
        noval

in the config file (which evaluates to 'true' with '--bool' option)?
Because from what I remember from the discussion on the 
"git config --null --list" format the lack of "\n" is used to
distinguish between noval (which is equivalent to 'true'), and empty
value (which is equivalent to 'false')

    [boolean
        noval        # equivalent to 'true'
        empty1 =     # equivalent to 'false'
        empty2 = ""  # equivalent to 'false'

> diff --git a/t/t9700/config.t b/t/t9700/config.t
> index 395a5c9..f0f7d2d 100644
> --- a/t/t9700/config.t
> +++ b/t/t9700/config.t
> @@ -16,6 +16,7 @@ in_empty_repo sub {
>  	$git->command_oneline("config", "foo.intval", "12g");
>  	$git->command_oneline("config", "foo.false.val", "false");
>  	$git->command_oneline("config", "foo.true.val", "yes");
> +	$git->command_oneline("config", "multiline.val", "hello\nmultiline.val=world");
>  
>  	my $conf = Git::Config->new();
>  	ok($conf, "constructed a new Git::Config");

-- 
Jakub Narebski
Poland
ShadeHawk on #git