Add a ‘latest-finished’ action

It redirects to the latest successful build from a finished
evaluation.  This is mostly useful for the Nixpkgs/NixOS mirroring
script, which need the latest finished evaluation in which some
aggregate job (such as ‘tested’ in NixOS) succeeded.

src/lib/Hydra/Base/Controller/ListBuilds.pm

@@ -119,4 +119,22 @@ sub latest_for : Chained('get_builds') PathPart('latest-for') {
 }
 
 
+# Redirect to the latest successful build in a finished evaluation
+# (i.e. an evaluation that has no unfinished builds).
+sub latest_finished : Chained('get_builds') PathPart('latest-finished') {
+    my ($self, $c, @rest) = @_;
+
+    my $latest = $c->stash->{allBuilds}->find(
+        { finished => 1, buildstatus => 0 },
+        { order_by => ["id DESC"], rows => 1, join => ["jobsetevalmembers"]
+        , where => \
+            "not exists (select 1 from jobsetevalmembers m2 join builds b2 on jobsetevalmembers.eval = m2.eval and m2.build = b2.id and b2.finished = 0)"
+        });
+
+    notFound($c, "There is no successful build to redirect to.") unless defined $latest;
+
+    $c->res->redirect($c->uri_for($c->controller('Build')->action_for("build"), [$latest->id], @rest));
+}
+
+
 1;

src/root/job.tt

@@ -24,6 +24,7 @@
   <div id="tabs-links" class="tab-pane">
     <ul>
       <li><a href="[% c.uri_for('/job' project.name jobset.name job.name 'latest') %]">Latest successful build</a></li>
+      <li><a href="[% c.uri_for('/job' project.name jobset.name job.name 'latest-finished') %]">Latest successful build from a finished evaluation</a></li>
       [% FOREACH system IN systems %]
         <li><a href="[% c.uri_for('/job' project.name jobset.name job.name 'latest-for' system.system) %]">Latest successful build for <tt>[% system.system %]</tt></a></li>
       [% END %]