dpkg-genchanges: Include .buildinfo files also for source-only uploads

The .buildinfo file also makes sense on source-only uploads, because it is
still a build. And more so when we have done a full build, but filtered the
changes to only include the sources in the upload.

In any case, this was the intended behavior from the beginning.

Closes: #846164

debian/changelog

@@ -31,6 +31,8 @@ dpkg (1.18.19) UNRELEASED; urgency=medium
     architectures for artifacts we are not going to distribute, and do not
     unnecessarily recompute the checksums for artifacts like the sources.
   * Do not compute the architecture list twice in dpkg-genchanges.
+  * Include .buildinfo files also for source-only uploads in dpkg-genchanges.
+    Closes: #846164
   * Portability:
     - On GNU/Hurd try to use the new process executable name attribute from
       libps, to properly match on start-stop-daemon --exec.

scripts/dpkg-genchanges.pl

@@ -313,6 +313,12 @@ error(g_('binary build with no binary artifacts found; cannot distribute'))
 foreach my $file ($dist->get_files()) {
     my $f = $file->{filename};
 
+    if (defined $file->{package} && $file->{package_type} eq 'buildinfo') {
+        # We always distribute the .buildinfo file.
+        $checksums->add_from_file("$uploadfilesdir/$f", key => $f);
+        next;
+    }
+
     # If this is a source-only upload, ignore any other artifacts.
     next if build_has_none(BUILD_BINARY);
 

scripts/t/dpkg_buildpackage/test-source_0_source.changes

@@ -19,9 +19,12 @@ Changes:
 Checksums-Sha1:
  0000000000000000000000000000000000000000 0 test-source_0.dsc
  0000000000000000000000000000000000000000 0 test-source_0.tar.xz
+ 0000000000000000000000000000000000000000 0 test-source_0_source.buildinfo
 Checksums-Sha256:
  0000000000000000000000000000000000000000000000000000000000000000 0 test-source_0.dsc
  0000000000000000000000000000000000000000000000000000000000000000 0 test-source_0.tar.xz
+ 0000000000000000000000000000000000000000000000000000000000000000 0 test-source_0_source.buildinfo
 Files:
  00000000000000000000000000000000 0 test optional test-source_0.dsc
  00000000000000000000000000000000 0 test optional test-source_0.tar.xz
+ 00000000000000000000000000000000 0 test optional test-source_0_source.buildinfo