Add 'nothing' set

3 files changed, 12 insertions, 0 deletions

diff --git a/doc/configuration/sets.html.part.in b/doc/configuration/sets.html.part.in
index 8e25722..6ced6ab 100644
--- a/doc/configuration/sets.html.part.in
+++ b/doc/configuration/sets.html.part.in
@@ -27,6 +27,9 @@
 
     <dt><code>insecurity</code></dt>
     <dd>The set of insecure packages (mostly for internal use).</dd>
+
+    <dt><code>nothing</code></dt>
+    <dd>An empty set.</dd>
 </dl>
 
 <p>Some sets, such as <code>system</code>, are made by combining sets from multiple repositories. For these sets, the
diff --git a/paludis/environment_implementation.cc b/paludis/environment_implementation.cc
index 6ed5ba9..c5236d6 100644
--- a/paludis/environment_implementation.cc
+++ b/paludis/environment_implementation.cc
@@ -307,6 +307,12 @@ namespace
         result->top()->append(std::make_shared<NamedSetDepSpec>(SetName("installed-packages")));
         return result;
     }
+
+    std::shared_ptr<const SetSpecTree> make_nothing_set()
+    {
+        std::shared_ptr<SetSpecTree> result(std::make_shared<SetSpecTree>(std::make_shared<AllDepSpec>()));
+        return result;
+    }
 }
 
 void
@@ -328,6 +334,8 @@ EnvironmentImplementation::populate_standard_sets() const
     if (_imp->sets.end() != _imp->sets.find(SetName("everything")))
         throw InternalError(PALUDIS_HERE, "something's still defining the 'everything' set");
     add_set(SetName("everything"), SetName("everything"), make_everything_set, false);
+
+    add_set(SetName("nothing"), SetName("nothing"), make_nothing_set, false);
 }
 
 namespace
diff --git a/paludis/repositories/e/e_repository_sets_TEST.cc b/paludis/repositories/e/e_repository_sets_TEST.cc
index e126833..ca7aaba 100644
--- a/paludis/repositories/e/e_repository_sets_TEST.cc
+++ b/paludis/repositories/e/e_repository_sets_TEST.cc
@@ -70,6 +70,7 @@ namespace test_cases
                     "insecurity::test-repo-1 "
                     "installed-packages installed-packages::default "
                     "installed-slots installed-slots::default "
+                    "nothing "
                     "security security::test-repo-1 set1 set1* "
                     "set1::test-repo-1 set1::test-repo-1* "
                     "system system::test-repo-1 world world::default");