scripts: Use // instead of || where appropriate

Replace only safe usages, i.e. those that fallback on initialization
values that evaluate to false anyway. Or when the API is explicit about
the variable being undefined.

scripts/Dpkg/Arch.pm

@@ -389,7 +389,7 @@ sub debarch_to_cpuattrs($)
     if (defined($cpu)) {
         abitable_load();
 
-        return ($abibits{$abi} || $cpubits{$cpu}, $cpuendian{$cpu});
+        return ($abibits{$abi} // $cpubits{$cpu}, $cpuendian{$cpu});
     } else {
         return;
     }

scripts/Dpkg/Changelog.pm

@@ -362,7 +362,7 @@ sub _data_range {
 
     my ($start, $end);
     if (defined($range->{count})) {
-	my $offset = $range->{offset} || 0;
+	my $offset = $range->{offset} // 0;
 	my $count = $range->{count};
 	# Convert count/offset in start/end
 	if ($offset > 0) {
@@ -416,8 +416,8 @@ sub abort_early {
 
     my $data = $self->{data} or return;
     my $r = $self->{range} or return;
-    my $count = $r->{count} || 0;
-    my $offset = $r->{offset} || 0;
+    my $count = $r->{count} // 0;
+    my $offset = $r->{offset} // 0;
 
     return if $self->_is_full_range($r);
     return if $offset < 0 or $count < 0;
@@ -537,8 +537,8 @@ sub dpkg {
     $f->{Source} = $src->get_source() || 'unknown';
     $f->{Version} = $src->get_version() // 'unknown';
     $f->{Distribution} = join(' ', $src->get_distributions());
-    $f->{Maintainer} = $src->get_maintainer() || '';
-    $f->{Date} = $src->get_timestamp() || '';
+    $f->{Maintainer} = $src->get_maintainer() // '';
+    $f->{Date} = $src->get_timestamp() // '';
     $f->{Changes} = $src->get_dpkg_changes();
 
     # handle optional fields
@@ -554,10 +554,10 @@ sub dpkg {
     }
 
     foreach my $bin (@data) {
-	my $oldurg = $f->{Urgency} || '';
-	my $oldurgn = $URGENCIES{$f->{Urgency}} || -1;
-	my $newurg = $bin->get_urgency() || '';
-	my $newurgn = $URGENCIES{$newurg} || -1;
+	my $oldurg = $f->{Urgency} // '';
+	my $oldurgn = $URGENCIES{$f->{Urgency}} // -1;
+	my $newurg = $bin->get_urgency() // '';
+	my $newurgn = $URGENCIES{$newurg} // -1;
 	$f->{Urgency} = ($newurgn > $oldurgn) ? $newurg : $oldurg;
 	$f->{Changes} .= "\n" . $bin->get_dpkg_changes();
 
@@ -602,8 +602,8 @@ sub rfc822 {
 	$f->{Source} = $entry->get_source() || 'unknown';
 	$f->{Version} = $entry->get_version() // 'unknown';
 	$f->{Distribution} = join(' ', $entry->get_distributions());
-	$f->{Maintainer} = $entry->get_maintainer() || '';
-	$f->{Date} = $entry->get_timestamp() || '';
+	$f->{Maintainer} = $entry->get_maintainer() // '';
+	$f->{Date} = $entry->get_timestamp() // '';
 	$f->{Changes} = $entry->get_dpkg_changes();
 
 	# handle optional fields

scripts/Dpkg/Changelog/Entry.pm

@@ -290,7 +290,7 @@ in the output format of C<dpkg-parsechangelog>.
 
 sub get_dpkg_changes {
     my ($self) = @_;
-    my $header = $self->get_part('header') || '';
+    my $header = $self->get_part('header') // '';
     $header =~ s/\s+$//;
     return "\n$header\n\n" . join("\n", @{$self->get_part('changes')});
 }

scripts/Dpkg/Compression/FileHandle.pm

@@ -419,7 +419,7 @@ sub open_for_read {
 
 sub cleanup {
     my ($self) = @_;
-    my $cmdline = *$self->{compressor}{cmdline} || '';
+    my $cmdline = *$self->{compressor}{cmdline} // '';
     *$self->{compressor}->wait_end_process(nocheck => *$self->{allow_sigpipe});
     if (*$self->{allow_sigpipe}) {
         unless (($? == 0) || (WIFSIGNALED($?) && (WTERMSIG($?) == SIGPIPE))) {

scripts/Dpkg/Deps.pm

@@ -523,7 +523,7 @@ sub new {
     $self->reset();
     $self->{host_arch} = $opts{host_arch} || Dpkg::Arch::get_host_arch();
     $self->{build_arch} = $opts{build_arch} || Dpkg::Arch::get_build_arch();
-    $self->{build_dep} = $opts{build_dep} || 0;
+    $self->{build_dep} = $opts{build_dep} // 0;
     $self->parse_string($arg) if defined($arg);
     return $self;
 }
@@ -1348,7 +1348,7 @@ sub add_installed_package {
 	package => $pkg,
 	version => $ver,
 	architecture => $arch,
-	multiarch => $multiarch || 'no',
+	multiarch => $multiarch // 'no',
     };
     $self->{pkg}{"$pkg:$arch"} = $p if defined $arch;
     push @{$self->{pkg}{$pkg}}, $p;

scripts/Dpkg/Package.pm

@@ -27,7 +27,7 @@ use Exporter qw(import);
 our @EXPORT = qw(pkg_name_is_illegal);
 
 sub pkg_name_is_illegal($) {
-    my $name = shift || '';
+    my $name = shift // '';
 
     if ($name eq '') {
         return _g('may not be empty string');

scripts/Dpkg/Shlibs/Objdump.pm

@@ -138,7 +138,7 @@ use Dpkg::ErrorHandling;
 
 sub new {
     my $this = shift;
-    my $file = shift || '';
+    my $file = shift // '';
     my $class = ref($this) || $this;
     my $self = {};
     bless $self, $class;

scripts/Dpkg/Shlibs/Symbol.pm

@@ -328,7 +328,7 @@ sub is_pattern {
 
 # Get pattern type if this symbol is a pattern.
 sub get_pattern_type {
-    return $_[0]->{pattern}{type} || '';
+    return $_[0]->{pattern}{type} // '';
 }
 
 # Get (sub)type of the alias pattern. Returns empty string if current
@@ -410,7 +410,7 @@ sub get_symbolspec {
     if ($template_mode) {
 	if ($self->has_tags()) {
 	    $spec .= sprintf('%s%3$s%s%3$s', $self->get_tagspec(),
-		$self->get_symboltempl(), $self->{symbol_quoted} || '');
+		$self->get_symboltempl(), $self->{symbol_quoted} // '');
 	} else {
 	    $spec .= $self->get_symboltempl();
 	}

scripts/Dpkg/Source/Patch.pm

@@ -65,7 +65,7 @@ sub set_header {
 sub add_diff_file {
     my ($self, $old, $new, %opts) = @_;
     $opts{include_timestamp} //= 0;
-    my $handle_binary = $opts{handle_binary_func} || sub {
+    my $handle_binary = $opts{handle_binary_func} // sub {
         my ($self, $old, $new, %opts) = @_;
         my $file = $opts{filename};
         $self->_fail_with_msg($file, _g('binary file contents changed'));
@@ -148,7 +148,7 @@ sub add_diff_directory {
     # TODO: make this function more configurable
     # - offer to disable some checks
     my $basedir = $opts{basedirname} || basename($new);
-    my $inc_removal = $opts{include_removal} || 0;
+    my $inc_removal = $opts{include_removal} // 0;
     my $diff_ignore;
     if ($opts{diff_ignore_func}) {
         $diff_ignore = $opts{diff_ignore_func};

scripts/Dpkg/Vendor/Ubuntu.pm

@@ -88,7 +88,7 @@ sub run_hook {
         my $fields = shift @params;
 
         # Add Launchpad-Bugs-Fixed field
-        my $bugs = find_launchpad_closes($fields->{'Changes'} || '');
+        my $bugs = find_launchpad_closes($fields->{'Changes'} // '');
         if (scalar(@$bugs)) {
             $fields->{'Launchpad-Bugs-Fixed'} = join(' ', @$bugs);
         }

scripts/dpkg-checkbuilddeps.pl

@@ -89,7 +89,7 @@ my @options_spec = (
 set_build_profiles(split(/,/, $bp_value)) if ($bp_value);
 my @build_profiles = get_build_profiles();
 
-my $controlfile = shift || 'debian/control';
+my $controlfile = shift // 'debian/control';
 
 my $control = Dpkg::Control::Info->new($controlfile);
 my $fields = $control->get_source();

scripts/dpkg-genchanges.pl

@@ -276,7 +276,7 @@ foreach (keys %{$src_fields}) {
 # Scan control info of all binary packages
 foreach my $pkg ($control->get_packages()) {
     my $p = $pkg->{'Package'};
-    my $a = $pkg->{'Architecture'} || '';
+    my $a = $pkg->{'Architecture'} // '';
     my $d = $pkg->{'Description'} || 'no description available';
     $d = $1 if $d =~ /^(.*)\n/;
     my $pkg_type = $pkg->{'Package-Type'} ||