From: Junio C Hamano <gitster@pobox.com>
Date: Sat, 02 Feb 2008 21:31:17 GMT
Subject: Re: [PATCH 1/2][Perlers?] git-send-email: ssh/login style password requests
Message-ID: <7vve5711wa.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <1201925161-9864-1-git-send-email-mfwitten@mit.edu>

Michael Witten <mfwitten@MIT.EDU> writes:

>  2 files changed, 53 insertions(+), 9 deletions(-)

Documentation part looks very clear.  Thanks.

> +		if (defined $smtp_authuser) {
> +
> +			if (!defined $smtp_authpass) {
> +				
> +				system "stty -echo";
> +
> +				do {
> +					$_ = $term->readline("Password: ");
> +				} while (!defined $_);
> +
> +				system "stty echo";
> +
> +				$smtp_authpass = $_ if ($_);
> +			}
> +

Another example which appears in PerlFAQ #8 uses ReadKey with
its ReadLine, like this:

    use Term::ReadKey;
    ReadMode('noecho');
    $password = ReadLine(0);

which is different from Term::ReadLine's "ReadLine".  An earlier
example you cited from perlfunc.pod's crypt() entry does:

    system "stty -echo";
    print "Password: ";
    chomp($word = <STDIN>);
    print "\n";
    system "stty echo";

In either case, I was worried about the interaction between the
Term::ReadLine backend implementation and "stty".

Actually, I just tried this myself:

    #!/usr/bin/perl -w

    use Term::ReadLine;
    my $term = new Term::ReadLine 'foobar';

    my ($user, $password);
    while (!defined $user) {
            $user = $term->readline("User: ");
    }
    system 'stty -echo';
    while (!defined $password) {
            $password = $term->readline("Password: ");
    }
    system 'stty echo';
    print "You said <$user><$password>\n";
    print "ReadLine backend used was ", $term->ReadLine, "\n";

In my case, the backend was "Term::ReadLine::Perl".  A few
problems:

 * After typing "junio <Enter>" to "User:", an extra newline is
   left before "Password:" prompt;

 * "Password:" prompt still echoed password "abc".  There was no
   extra newline before "You said <junio><abc>".

 * In either case, typing <Enter> returns an empty string from
   $term->readline() so the "while (!defined)" loop does not buy
   us anything.