Subject: Re: [PATCH 07/14] t7800-difftool.sh: Fix a test failure on Cygwin

From: David Aguilar <[email-masked]>
Date: Thu, 16 Dec 2010 18:33:59 -0800

On Tue, Dec 14, 2010 at 06:27:48PM +0000, Ramsay Jones wrote:
> 
> In particular, test 14 'difftool last flag wins' fails. This is
> caused by git-difftool.perl passing both GIT_DIFFTOOL_NO_PROMPT
> (='true') and GIT_DIFFTOOL_PROMPT (='true') to the difftool helper
> script. Despite the appropriate key being deleted from the ENV
> hash, it seems that once a key has been set in the hash, it gets
> passed along to the system() call. (ie deleting the key does not
> do the equivalent of unsetenv()).
> 
> In order to fix the problem, we keep track of the required prompt
> state while processing the arguments, and then set the relevant
> ENV hash key only once at the end.
> 
> Signed-off-by: Ramsay Jones <[email-masked]>
> ---
>  git-difftool.perl |   12 ++++++++----
>  1 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/git-difftool.perl b/git-difftool.perl
> index e95e4ad..ced1615 100755
> --- a/git-difftool.perl
> +++ b/git-difftool.perl
> @@ -52,6 +52,7 @@ sub generate_command
>  	my @command = (exe('git'), 'diff');
>  	my $skip_next = 0;
>  	my $idx = -1;
> +	my $prompt = '';

Would it be simpler to set $prompt = 1 and then
flip it to 0 when -y | or --no-prompt is supplied?

>  	for my $arg (@ARGV) {
>  		$idx++;
>  		if ($skip_next) {
> @@ -89,13 +90,11 @@ sub generate_command
>  			next;
>  		}
>  		if ($arg eq '-y' || $arg eq '--no-prompt') {
> -			$ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
> -			delete $ENV{GIT_DIFFTOOL_PROMPT};
> +			$prompt = 'no';
>  			next;
>  		}
>  		if ($arg eq '--prompt') {
> -			$ENV{GIT_DIFFTOOL_PROMPT} = 'true';
> -			delete $ENV{GIT_DIFFTOOL_NO_PROMPT};
> +			$prompt = 'yes';
>  			next;
>  		}
>  		if ($arg eq '-h' || $arg eq '--help') {
> @@ -103,6 +102,11 @@ sub generate_command
>  		}
>  		push @command, $arg;
>  	}
> +	if ($prompt eq 'yes') {

This would become:

	if ($prompt) {
		...
	}
	else {
		...
	}

> +		$ENV{GIT_DIFFTOOL_PROMPT} = 'true';
> +	} elsif ($prompt eq 'no') {
> +		$ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
> +	}
>  	return @command
>  }
>  
> -- 
> 1.7.3
> 
> 

-- 
		David