Bug #24670 for ack: Test failures when run detached from tty

This happens because ack only checks whether STDIN is a tty. The intent of the check is to see if data should be filtered from STDIN, which is assumed to be the case if STDIN is not a tty. However, I believe that if STDIN is not a tty and there's no data available on it (because it's closed or it's null/EOF), ack should proceed as normal. The test failures can be reproduced with: perl -e 'close(STDIN); print system("make","test")' I have attached a patch that checks for EOF on STDIN, which also allows this to succeed: cat /dev/null | make test In doing that, ack will now not treat null or closed STDIN as if it's running from a terminal, and yet "echo foo | ack foo" still works. The catch is that the following now fails to do the right thing: /bin/true | ack foo where /bin/true is any command that doesn't have output. A warning to STDERR may be appropriate in that case, along the lines of: ack: STDIN is not a terminal and has no data, ignoring

diff -ur --exclude=blib ack-1.58/ack ack-1.58-modified/ack --- ack-1.58/ack 2007-01-18 22:44:38.000000000 -0600 +++ ack-1.58-modified/ack 2007-03-02 11:51:54.000000000 -0600 @@ -159,7 +159,7 @@ $opt{show_filename} = (@what > 1) || (!-f $what[0]); } else { - my $is_filter = !-t STDIN; + my $is_filter = !-t STDIN && !eof(STDIN); if ( $is_filter ) { # We're going into filter mode for ( qw( f l ) ) { diff -ur --exclude=blib ack-1.58/ack-standalone ack-1.58-modified/ack-standalone --- ack-1.58/ack-standalone 2007-03-02 11:54:02.000000000 -0600 +++ ack-1.58-modified/ack-standalone 2007-03-02 11:55:11.000000000 -0600 @@ -157,7 +157,7 @@ $opt{show_filename} = (@what > 1) || (!-f $what[0]); } else { - my $is_filter = !-t STDIN; + my $is_filter = !-t STDIN && !eof(STDIN); if ( $is_filter ) { # We're going into filter mode for ( qw( f l ) ) {