patch, 14 partst7800-difftool.sh: Fix a test failure on Cygwin

> 
> 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 <ramsay@ramsay1.demon.co.uk>
> ---
>  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 = '';

>  	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') {

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

>> 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 $prompt = 1 and then
> flip it to 0 when -y | or --no-prompt is supplied?
> ...
>
> This would become:
>
> 	if ($prompt) {
> 		...
> 	}
> 	else {
> 		...
> 	}

> David Aguilar <davvid@gmail.com> writes:
> 
>>> 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 $prompt = 1 and then
>> flip it to 0 when -y | or --no-prompt is supplied?
>> ...
>>
>> This would become:
>>
>> 	if ($prompt) {
>> 		...
>> 	}
>> 	else {
>> 		...
>> 	}
> 
> But that is not what the patch does, is it?
> 
> Isn't it more like initializing $prompt to undef and then the above
> condition becomes:
> 
> 	if (!defined $prompt) {
>         	; # nothing
>         elsif ($prompt) {
> 		setenv PROMPT true
> 	} else {
> 		setenv NO_PROMPT true
> 	}
> 
> no?