Test the fake derivations channel, asserting nested packages are properly represented.

This is a breaking change. Previously, packages named `packageset.foo`
would be exposed in the fake derivation channel as `packageset-foo`.

Presumably this was done to avoid needing to track attribute sets, and
to avoid the complexity. I think this now correctly handles the
complexity and properly mirrors the input expressions layout.

src/lib/Hydra/View/NixExprs.pm

@@ -4,10 +4,11 @@ use strict;
 use base qw/Catalyst::View/;
 use Hydra::Helper::Nix;
 use Hydra::Helper::Escape;
+use Hydra::Helper::AttributeSet;
 use Archive::Tar;
 use IO::Compress::Bzip2 qw(bzip2);
 use Encode;
-
+use Data::Dumper;
 
 
 sub process {
@@ -56,14 +57,15 @@ EOF
     foreach my $system (keys %perSystem) {
         $res .= "else " if !$first;
         $res .= "if system == ${\escapeString $system} then {\n\n";
-
+        my $attrsets = Hydra::Helper::AttributeSet->new();
         foreach my $job (keys %{$perSystem{$system}}) {
             my $pkg = $perSystem{$system}->{$job};
             my $build = $pkg->{build};
-            $res .= "  # Hydra build ${\$build->id}\n";
             my $attr = $build->get_column('job');
-            $attr =~ s/\./-/g;
+            $attrsets->registerValue($attr);
-            $res .= "  ${\escapeString $attr} = (mkFakeDerivation {\n";
+
+            $res .= "  # Hydra build ${\$build->id}\n";
+            $res .= "  ${\escapeAttributePath $attr} = (mkFakeDerivation {\n";
             $res .= "    type = \"derivation\";\n";
             $res .= "    name = ${\escapeString ($build->get_column('releasename') or $build->nixname)};\n";
             $res .= "    system = ${\escapeString $build->system};\n";
@@ -82,6 +84,10 @@ EOF
             $res .= "  }).$out;\n\n";
         }
 
+        for my $attrset ($attrsets->enumerate()) {
+            $res .= "  ${\escapeAttributePath $attrset}.recurseForDerivations = true;\n\n";
+        }
+
         $res .= "}\n\n";
         $first = 0;
     }

t/Controller/Jobset/channel.t

@@ -0,0 +1,62 @@
+use feature 'unicode_strings';
+use strict;
+use Setup;
+use IO::Uncompress::Bunzip2 qw(bunzip2);
+use Archive::Tar;
+use JSON qw(decode_json);
+use Data::Dumper;
+my %ctx = test_init();
+
+require Hydra::Schema;
+require Hydra::Model::DB;
+require Hydra::Helper::Nix;
+
+use Test2::V0;
+require Catalyst::Test;
+Catalyst::Test->import('Hydra');
+
+my $db = Hydra::Model::DB->new;
+hydra_setup($db);
+
+my $project = $db->resultset('Projects')->create({name => "tests", displayname => "", owner => "root"});
+
+# Most basic test case, no parameters
+my $jobset = createBaseJobset("nested-attributes", "nested-attributes.nix", $ctx{jobsdir});
+
+ok(evalSucceeds($jobset));
+is(nrQueuedBuildsForJobset($jobset), 4);
+
+for my $build (queuedBuildsForJobset($jobset)) {
+    ok(runBuild($build), "Build '".$build->job."' should exit with code 0");
+    my $newbuild = $db->resultset('Builds')->find($build->id);
+    is($newbuild->finished, 1, "Build '".$build->job."' should be finished.");
+    is($newbuild->buildstatus, 0, "Build '".$build->job."' should have buildstatus 0.");
+}
+
+my $compressed = get('/jobset/tests/nested-attributes/channel/latest/nixexprs.tar.bz2');
+my $tarcontent;
+bunzip2(\$compressed => \$tarcontent);
+open(my $tarfh, "<", \$tarcontent);
+my $tar = Archive::Tar->new($tarfh);
+
+my $defaultnix = $ctx{"tmpdir"} . "/channel-default.nix";
+$tar->extract_file("channel/default.nix", $defaultnix);
+
+print STDERR $tar->get_content("channel/default.nix");
+
+(my $status, my $stdout, my $stderr) = Hydra::Helper::Nix::captureStdoutStderr(5, "nix-env", "--json", "--query", "--available", "--attr-path", "--file", $defaultnix);
+is($stderr, "", "Stderr should be empty");
+is($status, 0, "Querying the packages should succeed");
+
+my $packages = decode_json($stdout);
+my $keys = [sort keys %$packages];
+is($keys, [
+    "packageset-nested",
+    "packageset.deeper.deeper.nested",
+    "packageset.nested",
+    "packageset.nested2",
+]);
+is($packages->{"packageset-nested"}->{"name"}, "actually-top-level");
+is($packages->{"packageset.nested"}->{"name"}, "actually-nested");
+
+done_testing;

t/jobs/nested-attributes.nix

@@ -0,0 +1,36 @@
+with import ./config.nix;
+rec {
+  # Given a jobset containing a package set named X with an interior member Y,
+  # expose the interior member Y with the name X-Y. This is to exercise a bug
+  # in the NixExprs view's generated Nix expression which flattens the
+  # package set namespace from `X.Y` to `X-Y`. If the bug is present, the
+  # resulting expression incorrectly renders two `X-Y` packages.
+  packageset = {
+    recurseForDerivations = true;
+    deeper = {
+      recurseForDerivations = true;
+      deeper = {
+        recurseForDerivations = true;
+
+        nested = mkDerivation {
+          name = "much-too-deep";
+          builder = ./empty-dir-builder.sh;
+        };
+      };
+    };
+
+    nested = mkDerivation {
+      name = "actually-nested";
+      builder = ./empty-dir-builder.sh;
+    };
+
+    nested2 = mkDerivation {
+      name = "actually-nested2";
+      builder = ./empty-dir-builder.sh;
+    };
+  };
+  packageset-nested = mkDerivation {
+    name = "actually-top-level";
+    builder = ./empty-dir-builder.sh;
+  };
+}