allow librarian exclusion declaration as a noop

CHANGELOG.mkd

@@ -3,6 +3,7 @@ CHANGELOG
 
 Unreleased
 ----------
+- allow librarian exclusion declaration as a noop
 
 4.1.0
 -----

lib/r10k/module_loader/puppetfile/dsl.rb

@@ -33,6 +33,10 @@ def moduledir(location)
           @librarian.set_moduledir(location)
         end
 
+        def exclusion(name)
+          # noop
+        end
+
         def method_missing(method, *args)
           raise NoMethodError, _("unrecognized declaration '%{method}'") % {method: method}
         end

spec/fixtures/unit/puppetfile/exclusion/Puppetfile

@@ -0,0 +1,4 @@
+forge 'https://forgeapi.puppetlabs.com'
+
+mod 'puppetlabs/stdlib', '9.6.0'
+exclusion 'emacs'  # yuck

spec/unit/module_loader/puppetfile_spec.rb

@@ -304,6 +304,14 @@ def expect_wrapped_error(error, pf_path, error_type)
       end
     end
 
+    describe 'exclusion declaration' do
+      it 'is ignored and does not raise an exception' do
+        @path = File.join(PROJECT_ROOT, 'spec', 'fixtures', 'unit', 'puppetfile', 'exclusion')
+        puppetfile = R10K::ModuleLoader::Puppetfile.new(basedir: @path)
+        puppetfile.load!
+      end
+    end
+
     it 'rejects Puppetfiles with duplicate module names' do
       @path = File.join(PROJECT_ROOT, 'spec', 'fixtures', 'unit', 'puppetfile', 'duplicate-module-error')
       pf_path = File.join(@path, 'Puppetfile')