build: Add CPAN distribution machinery

Add a new dist-cpan target that takes care of preparing a perl
distribution to be uploaded to CPAN. Only the modules are shipped,
some of which do require dpkg tools being installed though.

Closes: #821177

7 files changed, 152 insertions, 5 deletions

diff --git a/Makefile.am b/Makefile.am
index 31e82a7a8..4cd8376f6 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -179,9 +179,11 @@ update-po:
 	$(MAKE) -C dselect/po update-po
 	$(MAKE) -C man update-po
 
+include $(top_srcdir)/cpan.am
+
 # If we create the dist tarball from the git repository, make sure
 # that we're not forgetting some files...
-dist-hook:
+dist-hook: dist-cpan
 	echo $(VERSION) >$(distdir)/.dist-version
 	if [ -e .git ]; then \
 	  for file in `git ls-files | grep -v .gitignore`; do \
diff --git a/configure.ac b/configure.ac
index 2e09c63e1..822f6f654 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,8 +3,14 @@
 m4_pattern_forbid([^_?DPKG_])
 
 AC_PREREQ(2.60)
-AC_INIT([dpkg], m4_esyscmd([./get-version]), [debian-dpkg@lists.debian.org])
+AC_INIT([dpkg], m4_esyscmd([./get-version]), [debian-dpkg@lists.debian.org],
+        [dpkg], [https://wiki.debian.org/Teams/Dpkg])
 AC_SUBST([PACKAGE_COPYRIGHT_HOLDER], ['Dpkg Developers'])
+AC_SUBST([PACKAGE_VCS_TYPE], [git])
+AC_SUBST([PACKAGE_VCS_URL], [https://anonscm.debian.org/git/dpkg/dpkg.git])
+AC_SUBST([PACKAGE_VCS_WEB], [https://anonscm.debian.org/cgit/dpkg/dpkg.git])
+AC_SUBST([PACKAGE_BUG_WEB], [https://bugs.debian.org/src:dpkg])
+AC_SUBST([PACKAGE_CPAN_NAME], [Dpkg])
 AC_CONFIG_SRCDIR([lib/dpkg/dpkg.h])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR([build-aux])
@@ -208,6 +214,7 @@ AC_CONFIG_FILES([
   doc/Doxyfile
   man/Makefile
   po/Makefile.in
+  scripts/Build.PL
   scripts/Makefile
   scripts/mk/Makefile
   scripts/po/Makefile.in
diff --git a/cpan.am b/cpan.am
new file mode 100644
index 000000000..0cf4967ad
--- /dev/null
+++ b/cpan.am
@@ -0,0 +1,48 @@
+CPAN_DIST_NAME = $(PACKAGE_CPAN_NAME)
+CPAN_DIST_VERSION = $(PACKAGE_VERSION)
+CPAN_DIST = $(CPAN_DIST_NAME)-$(CPAN_DIST_VERSION)
+CPAN_DIST_ARCHIVE = $(CPAN_DIST).tar.gz
+
+dist-cpan:
+	: # Create the CPAN source tree.
+	mkdir -p $(CPAN_DIST)
+	mkdir -p $(CPAN_DIST)/lib
+	mkdir -p $(CPAN_DIST)/t
+	cp -fpR $(top_srcdir)/data $(CPAN_DIST)
+	cp -fpR $(top_srcdir)/t/* \
+	         $(top_srcdir)/scripts/t/Dpkg* \
+	         $(top_srcdir)/scripts/t/origins \
+	         $(CPAN_DIST)/t
+	$(do_perl_subst) <$(top_srcdir)/scripts/Dpkg.pm \
+	                 >$(CPAN_DIST)/lib/Dpkg.pm
+	cp -fpR $(top_srcdir)/scripts/Dpkg.pm \
+	         $(top_srcdir)/scripts/Dpkg \
+	         $(CPAN_DIST)/lib/
+	cp -fpR $(top_srcdir)/scripts/Test $(CPAN_DIST)/lib/
+	cp -fpR $(top_srcdir)/scripts/Build.PL $(CPAN_DIST)
+
+	: # Fix permissions of the distributed files.
+	chmod a+x $(CPAN_DIST)/Build.PL
+	find $(CPAN_DIST) \
+	       -type d ! -perm 755 -exec chmod u+rwx,go+rx {} ';' -o \
+	     ! -type d ! -perm -444 -links 1 -exec chmod a+r {} \; -o \
+	     ! -type d ! -perm -400 -exec chmod a+r {} \; -o \
+	     ! -type d ! -perm -444 -exec $(install_sh) -c -m a+r {} {} \; || \
+	  chmod -R a+r $(CPAN_DIST)
+
+	: # Prepare the CPAN distribution.
+	cd $(CPAN_DIST) && ./Build.PL
+	cd $(CPAN_DIST) && ./Build manifest
+	cd $(CPAN_DIST) && ./Build distsign
+
+	: # Pack the CPAN distribution.
+	$(TAR) -caf $(CPAN_DIST_ARCHIVE) -C $(CPAN_DIST) -Hustar \
+	  --sort=name --owner=root:0 --group=root:0 $(CPAN_DIST)
+
+	: # Cleanup the CPAN source tree.
+	find $(CPAN_DIST) -type d ! -perm -200 -exec chmod u+w {} ';'
+	rm -rf $(CPAN_DIST)
+
+# Ignore the CPAN archive for distcleancheck.
+distcleancheck_listfiles = \
+	find -type f \( -name $(CPAN_DIST_ARCHIVE) -o -print \)
diff --git a/debian/changelog b/debian/changelog
index 59d2cffd6..372dcdcde 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -90,6 +90,7 @@ dpkg (1.19.1) UNRELEASED; urgency=medium
       instead of passing the positive form manually.
     - Enable clang -Wdocumentation warning if available.
     - Enable gcc-7 -Wregister warning if available.
+    - Add CPAN distribution machinery for the perl modules. Closes: #821177
   * Packaging:
     - Install update-alternatives policykit-1 file.
     - Add Breaks to libdpkg-perl against pkg-kde-tools (<< 0.15.28~), as
diff --git a/scripts/.gitignore b/scripts/.gitignore
index 0d1f29ac9..a93412826 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -1,3 +1,4 @@
+Build.PL
 dpkg-architecture
 dpkg-buildflags
 dpkg-buildpackage
diff --git a/scripts/Build.PL.in b/scripts/Build.PL.in
new file mode 100644
index 000000000..40de90e41
--- /dev/null
+++ b/scripts/Build.PL.in
@@ -0,0 +1,74 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+use Module::Build ();
+
+if (-e 'Build.PL.in') {
+    die "error: This is an in-tree build, not a proper perl distribution.\n" .
+        "To create one please configure normally and then run 'make dist'.\n";
+}
+
+my $class = Module::Build->subclass(
+    class => 'Module::Build::Dpkg',
+    code => q{
+        BEGIN {
+            $ENV{DPKG_TEST_MODE} = 'cpan';
+            $ENV{DPKG_DATADIR} = 'data';
+            $ENV{DPKG_ORIGINS_DIR} = 't/origins';
+        }
+    },
+);
+
+my $build = $class->new(
+    dist_name       => '@PACKAGE_CPAN_NAME@',
+    dist_abstract   => 'Debian Package Manager Perl modules',
+    dist_version    => '@PACKAGE_VERSION@',
+    dist_author     => '@PACKAGE_COPYRIGHT_HOLDER@ <@PACKAGE_BUGREPORT@>',
+    license         => 'GPL_2',
+
+    # Set only to avoid warnings.
+    module_name     => '@PACKAGE_CPAN_NAME@',
+
+    meta_merge => {
+        resources => {
+            homepage => '@PACKAGE_URL@',
+            repository => {
+                type => '@PACKAGE_VCS_TYPE@',
+                url => '@PACKAGE_VCS_URL@',
+                web => '@PACKAGE_VCS_WEB@',
+            },
+            bugtracker => {
+                web => '@PACKAGE_BUG_WEB@',
+            },
+        },
+        keywords => [ qw(dpkg debian perl) ],
+    },
+
+    sign            => 1,
+    dynamic_config  => 0,
+
+    configure_requires => {
+        'Module::Build'         => '0.4004',
+    },
+    test_requires => {
+        'TAP::Harness'          => 0,
+        'Test::More'            => 0,
+        'Test::Pod'             => 0,
+        'Test::Strict'          => 0,
+    },
+    recommands => {
+        'Algorithm::Merge'      => 0,
+        'File::FcntlLock'       => 0,
+        'Locale::gettext'       => 0,
+
+    },
+    requires => {
+        'perl'                  => '@PERL_MIN_VERSION@',
+    },
+);
+
+$build->create_build_script();
+
+1;
diff --git a/scripts/Test/Dpkg.pm b/scripts/Test/Dpkg.pm
index 5eea6184a..4900e1f91 100644
--- a/scripts/Test/Dpkg.pm
+++ b/scripts/Test/Dpkg.pm
@@ -54,6 +54,12 @@ use File::Path qw(make_path);
 use IPC::Cmd qw(can_run);
 use Test::More;
 
+my $test_mode;
+
+BEGIN {
+    $test_mode = $ENV{DPKG_TEST_MODE} // 'dpkg';
+}
+
 sub _test_get_caller_dir
 {
     my (undef, $path, undef) = caller 1;
@@ -69,8 +75,12 @@ sub test_get_data_path
     my $path = shift;
 
     if (defined $path) {
-        my $srcdir = $ENV{srcdir} || '.';
-        return "$srcdir/$path";
+        if ($test_mode eq 'cpan') {
+            return $path;
+        } else {
+            my $srcdir = $ENV{srcdir} || '.';
+            return "$srcdir/$path";
+        }
     } else {
         return _test_get_caller_dir();
     }
@@ -87,7 +97,11 @@ sub test_get_temp_path
 
 sub test_get_perl_dirs
 {
-    return qw(t src/t lib utils/t scripts dselect);
+    if ($test_mode eq 'cpan') {
+        return qw(t lib);
+    } else {
+        return qw(t src/t lib utils/t scripts dselect);
+    }
 }
 
 sub all_perl_files