[Debconf-devel] Bug#651642: debconf: process_command does not properly skip blank input lines.

[Bob Vincent]

Package: debconf
Version: 1.5.40ubuntu1
Severity: normal

This is related to bug reports #630772 and #637737

When purging old kernels from the command line, multiple "Use of uninitialized value $command" errors are displayed.  These errors are caused by the following code line:

      return 1 unless defined && ! /^\s*#/; # Skip blank lines, comments.

The code skips undefined input and comments, but the associated inline comment claims that the intent was to skip blank lines and comments.  I resolved the problem locally by making the following change:

diff --git a/Debconf/ConfModule.pm b/Debconf/ConfModule.pm
index 8017202..20c084e 100644
--- a/Debconf/ConfModule.pm
+++ b/Debconf/ConfModule.pm
@@ -228,7 +228,9 @@ sub process_command {
 	my $this=shift;
 	
 	debug developer => "<-- $_";
-	return 1 unless defined && ! /^\s*#/; # Skip blank lines, comments.
+	return 1 unless defined; # Skip empty input.
+	return 1 if /^\s*$/ # Skip blank lines.
+	return 1 if /^\s*#/ # Skip comments.
 	chomp;
 	my ($command, @params);
 	if (defined $this->client_capb and grep { $_ eq 'escape' } @{$this->client_capb}) {


-- System Information:
Debian Release: wheezy/sid
  APT prefers oneiric-updates
  APT policy: (500, 'oneiric-updates'), (500, 'oneiric'), (100, 'oneiric-backports')
Architecture: i386 (i686)

Kernel: Linux 3.2.0-rc5+ (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_US.UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages debconf depends on:
ii  perl-base                     5.12.4-4   minimal Perl system

Versions of packages debconf recommends:
ii  apt-utils            0.8.16~exp5ubuntu13 APT utility programs
ii  debconf-i18n         1.5.40ubuntu1       full internationalization support 

Versions of packages debconf suggests:
pn  debconf-doc             <none>           (no description available)
ii  debconf-utils           1.5.40ubuntu1    debconf utilities
ii  dialog                  1.1-20110707-1   Displays user-friendly dialog boxe
ii  libgtk2-perl            2:1.223-1build2  Perl interface to the 2.x series o
pn  libnet-ldap-perl        <none>           (no description available)
pn  libqtcore4-perl         <none>           (no description available)
pn  libqtgui4-perl          <none>           (no description available)
pn  libterm-readline-gnu-pe <none>           (no description available)
ii  perl                    5.12.4-4         Larry Wall's Practical Extraction 
ii  whiptail                0.52.11-2ubuntu8 Displays user-friendly dialog boxe

-- debconf information:
  debconf-apt-progress/title:
  debconf-apt-progress/info:
  debconf/priority: high
  debconf-apt-progress/preparing:
  debconf-apt-progress/media-change:
* debconf/frontend: Dialog
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