difftool: exit(0) when usage is printed

Prior to this commit, the script exited with an error whenever the
usage string was printed, regardless of the reason it was done. In
cases where usage was printed due to a user request (e.g. '-h'
option), the script should exit without error (exit 0).

This commit adds an argument to the usage function that allows the
exit code to be specified when the function is called.

Signed-off-by: Tim Henigan <tim.henigan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-difftool.perl b/git-difftool.perl
index 93e84e8d3da8a88d6517a5174e650cf102343542..4555cd8b1c5b8cda4527b328b858a015ac75d357 100755 (executable)
--- a/git-difftool.perl
+++ b/git-difftool.perl
@@ -20,6 +20,7 @@
 
 sub usage
 {
+       my $exitcode = shift;
        print << 'USAGE';
 usage: git difftool [-t|--tool=<tool>]
                     [-x|--extcmd=<cmd>]
@@ -27,7 +28,7 @@ sub usage
                     [--prompt] [-y|--no-prompt]
                     ['git diff' options]
 USAGE
-       exit 1;
+       exit($exitcode);
 }
 
 sub setup_environment
@@ -58,14 +59,14 @@ sub exe
        'x|extcmd:s' => \$extcmd);
 
 if (defined($help)) {
-       usage();
+       usage(0);
 }
 if (defined($difftool_cmd)) {
        if (length($difftool_cmd) > 0) {
                $ENV{GIT_DIFF_TOOL} = $difftool_cmd;
        } else {
                print "No <tool> given for --tool=<tool>\n";
-               usage();
+               usage(1);
        }
 }
 if (defined($extcmd)) {
@@ -73,7 +74,7 @@ sub exe
                $ENV{GIT_DIFFTOOL_EXTCMD} = $extcmd;
        } else {
                print "No <cmd> given for --extcmd=<cmd>\n";
-               usage();
+               usage(1);
        }
 }
 if ($gui) {