[PATCH 10/9 v5] difftool: fix regression in '--prompt' options

[Tim Henigan <tim.henigan@gmail.com>]

When difftool was changed to use Getopt::Long, it changed the way
that the '--prompt' and '--no-prompt' options were handled. The
expected behavior is that the two options may be given any number
of times. The last option given "wins".

For example, if a user sets "[alias] mdt = difftool --prompt", the
following must still run without error:

$ git mdt --no-prompt

The changes made during the switch to Getopt::Long broke this
behavior. This commit teaches difftool to handle them properly
again.

Signed-off-by: Tim Henigan <tim.henigan@gmail.com>
---

This replaces 10/9 in the previous version of the series.

Changes in v5:
  - Based on an example provided by Thomas Rast on the Git dev list,
    the '--[no-]prompt' options are parsed by Getopt::Long again.


 git-difftool.perl |   21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/git-difftool.perl b/git-difftool.perl
index 9f0f9a9..9892d1e 100755
--- a/git-difftool.perl
+++ b/git-difftool.perl
@@ -29,8 +29,8 @@ sub usage
 	my $exitcode = shift;
 	print << 'USAGE';
 usage: git difftool [-t|--tool=<tool>] [--tool-help]
-                    [-x|--extcmd=<cmd>]
-                    [-y|--no-prompt]   [-g|--gui]
+                    [-x|--extcmd=<cmd>] [-g|--gui]
+                    [--prompt] [-y|--no-prompt]
                     [-d|--dir-diff]
                     ['git diff' options]
 USAGE
@@ -131,15 +131,15 @@ sub setup_dir_diff
 
 # parse command-line options. all unrecognized options and arguments
 # are passed through to the 'git diff' command.
-my ($difftool_cmd, $dirdiff, $extcmd, $gui, $help, $no_prompt, $prompt, $tool_help);
+my ($difftool_cmd, $dirdiff, $extcmd, $gui, $help, $prompt, $tool_help);
 GetOptions('g|gui' => \$gui,
 	'd|dir-diff' => \$dirdiff,
 	'h' => \$help,
-	'prompt' => \$prompt,
+	'prompt!' => \$prompt,
+	'y' => sub { $prompt = 0; },
 	't|tool:s' => \$difftool_cmd,
 	'tool-help' => \$tool_help,
-	'x|extcmd:s' => \$extcmd,
-	'y|no-prompt' => \$no_prompt);
+	'x|extcmd:s' => \$extcmd);
 
 if (defined($help)) {
 	usage(0);
@@ -203,10 +203,11 @@ if (defined($dirdiff)) {
 	}
 } else {
 	if (defined($prompt)) {
-		$ENV{GIT_DIFFTOOL_PROMPT} = 'true';
-	}
-	elsif (defined($no_prompt)) {
-		$ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
+		if ($prompt) {
+			$ENV{GIT_DIFFTOOL_PROMPT} = 'true';
+		} else {
+			$ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
+		}
 	}
 
 	$ENV{GIT_PAGER} = '';
-- 
1.7.10.rc1.40.g756bbcd