Bug#943586: lintian: confusing usage+internal+warning messages on binary packages

[Guillem Jover <guillem@debian.org>]

Package: lintian
Version: 2.30.0
Severity: normal

Hi!

I'm getting this when checking a binary package explicitly, which is
rather confusing when not using the --verbose option, as I initially
thought it did not lint the package at all:

  ,---
  $ lintian -v libdpkg-dev_1.20.0_amd64.deb
  N: Using profile debian/main.
  N: Starting on group dpkg/1.20.0
  N: Unpacking packages in group dpkg/1.20.0
  N: ----
  N: Processing binary package libdpkg-dev (version 1.20.0, arch amd64) ...
  Usage: Lintian::files::empty_package::_set_is_dummy(self, newvalue) at /usr/share/lintian/checks/files/empty-package.pm line 42.
  internal error: cannot run files check on package binary:libdpkg-dev/1.20.0/amd64
  warning: skipping check of binary:libdpkg-dev/1.20.0/amd64
  N: Finished processing group dpkg/1.20.0
  `---

And the package is definitely not empty, I've tried with others and it
shows the same.

Thanks,
Guillem