dpkg-source: new --unapply-patches option

This option is used by source formats 2.0 and 3.0 (quilt) to unapply
patches after a successful build. It's useful for people who manage their
packages in a VCS repository and prefer to have patches unapplied, even
after a package build.

Given that this option is a matter of personal taste, do not allow it
in debian/source/options so that the resulting source package cannot
have this behaviour by default and so that all source packages behave
in a consistent way: patches applied by default is a major feature
of the new formats.

2 files changed, 50 insertions, 0 deletions

diff --git a/scripts/Dpkg/Source/Package/V2.pm b/scripts/Dpkg/Source/Package/V2.pm
index 787d6acd6..3c7082121 100644
--- a/scripts/Dpkg/Source/Package/V2.pm
+++ b/scripts/Dpkg/Source/Package/V2.pm
@@ -53,6 +53,8 @@ sub init_options {
         unless exists $self->{'options'}{'preparation'};
     $self->{'options'}{'skip_patches'} = 0
         unless exists $self->{'options'}{'skip_patches'};
+    $self->{'options'}{'unapply_patches'} = 0
+        unless exists $self->{'options'}{'unapply_patches'};
     $self->{'options'}{'skip_debianization'} = 0
         unless exists $self->{'options'}{'skip_debianization'};
     $self->{'options'}{'create_empty_orig'} = 0
@@ -76,6 +78,9 @@ sub parse_cmdline_option {
     } elsif ($opt =~ /^--skip-patches$/) {
         $self->{'options'}{'skip_patches'} = 1;
         return 1;
+    } elsif ($opt =~ /^--unapply-patches$/) {
+        $self->{'options'}{'unapply_patches'} = 1;
+        return 1;
     } elsif ($opt =~ /^--skip-debianization$/) {
         $self->{'options'}{'skip_debianization'} = 1;
         return 1;
@@ -206,6 +211,23 @@ sub apply_patches {
     close(APPLIED);
 }
 
+sub unapply_patches {
+    my ($self, $dir, %opts) = @_;
+    my @patches = reverse($self->get_patches($dir, %opts));
+    return unless scalar(@patches);
+    my $timestamp = time();
+    my $applied = File::Spec->catfile($dir, "debian", "patches", ".dpkg-source-applied");
+    foreach my $patch (@patches) {
+        my $path = File::Spec->catfile($dir, "debian", "patches", $patch);
+        info(_g("unapplying %s"), $patch) unless $opts{"quiet"};
+        my $patch_obj = Dpkg::Source::Patch->new(filename => $path);
+        $patch_obj->apply($dir, force_timestamp => 1,
+                          timestamp => $timestamp,
+                          add_options => [ '-E', '-R' ]);
+    }
+    unlink($applied);
+}
+
 sub can_build {
     my ($self, $dir) = @_;
     return 1 if $self->find_original_tarballs(include_supplementary => 0);
@@ -219,6 +241,11 @@ sub before_build {
     $self->check_patches_applied($dir) if $self->{'options'}{'preparation'};
 }
 
+sub after_build {
+    my ($self, $dir) = @_;
+    $self->unapply_patches($dir) if $self->{'options'}{'unapply_patches'};
+}
+
 sub prepare_build {
     my ($self, $dir) = @_;
     $self->{'diff_options'} = {
diff --git a/scripts/Dpkg/Source/Package/V3/quilt.pm b/scripts/Dpkg/Source/Package/V3/quilt.pm
index bb9030005..ad352d32e 100644
--- a/scripts/Dpkg/Source/Package/V3/quilt.pm
+++ b/scripts/Dpkg/Source/Package/V3/quilt.pm
@@ -227,6 +227,29 @@ sub apply_patches {
     close(APPLIED);
 }
 
+sub unapply_patches {
+    my ($self, $dir, %opts) = @_;
+
+    $opts{'verbose'} = 1 unless defined $opts{'verbose'};
+
+    my $pc_applied = File::Spec->catfile($dir, ".pc", "applied-patches");
+    my @applied = $self->read_patch_list($pc_applied);
+    $opts{"timestamp"} = time();
+    foreach my $patch (reverse @applied) {
+        my $path = File::Spec->catfile($dir, "debian", "patches", $patch);
+        my $obj = Dpkg::Source::Patch->new(filename => $path);
+
+        info(_g("unapplying %s"), $patch) if $opts{"verbose"};
+        $obj->apply($dir, timestamp => $opts{"timestamp"},
+                    force_timestamp => 1, remove_backup => 0,
+                    options => [ '-R', '-s', '-t', '-N', '-p1',
+                                 '-u', '-V', 'never', '-g0', '-E',
+                                 '--no-backup-if-mismatch' ]);
+        erasedir(File::Spec->catdir($dir, ".pc", $patch));
+    }
+    unlink($pc_applied);
+}
+
 sub prepare_build {
     my ($self, $dir) = @_;
     $self->SUPER::prepare_build($dir);