From: Peter Rabbitson <ribasushi@cpan.org>
Date: Tue, 14 Feb 2012 22:05:04 +0000 (+0100)
Subject: Add a TODO test for a very elaborate stack leak scenario
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=187ec69a5cabfd5ab651f6e4a6a8b3d59579c94f;p=dbsrgits%2FDBIx-Class-Historic.git

Add a TODO test for a very elaborate stack leak scenario
---

diff --git a/t/52leaks.t b/t/52leaks.t
index ea055a6..aefd001 100644
--- a/t/52leaks.t
+++ b/t/52leaks.t
@@ -145,6 +145,11 @@ my @compose_ns_classes;
       cds => [{
         title => 'foo cd',
         year => 1984,
+        tracks => [
+          { title => 't1' },
+          { title => 't2' },
+        ],
+        genre => { name => 'mauve' },
       }],
     });
 
@@ -155,6 +160,15 @@ my @compose_ns_classes;
     return ($artist, $pg, $pg_wcount);
   });
 
+  # same for dbh_do
+  my ($rs_bind_circref, $cond_rowobj) = $schema->storage->dbh_do ( sub {
+    my $row = $_[0]->schema->resultset('Artist')->new({});
+    my $rs = $_[0]->schema->resultset('Artist')->search({
+      name => $row,  # this is deliberately bogus, see FIXME below!
+    });
+    return ($rs, $row);
+  });
+
   is ($pager->next_page, 3, 'There is one more page available');
 
   # based on 66 per 10 pages
@@ -222,11 +236,17 @@ my @compose_ns_classes;
 
     row_object => $row_obj,
 
+    mc_row_object => $mc_row_obj,
+
     result_source => $rs->result_source,
 
     result_source_handle => $rs->result_source->handle,
 
     pager_explicit_count => $pager_explicit_count,
+
+    leaky_resultset => $rs_bind_circref,
+    leaky_resultset_cond => $cond_rowobj,
+    leaky_resultset_member => $rs_bind_circref->next,
   };
 
   require Storable;
@@ -263,8 +283,13 @@ my @compose_ns_classes;
     $base_collection->{"DBI handle $_"} = $_;
   }
 
-  if ( DBIx::Class::Optional::Dependencies->req_ok_for ('test_leaks') ) {
-    Test::Memory::Cycle::memory_cycle_ok ($base_collection, 'No cycles in the object collection')
+  SKIP: {
+    if ( DBIx::Class::Optional::Dependencies->req_ok_for ('test_leaks') ) {
+      Test::Memory::Cycle::memory_cycle_ok ($base_collection, 'No cycles in the object collection')
+    }
+    else {
+      skip 'Circular ref test needs ' .  DBIx::Class::Optional::Dependencies->req_missing_for ('test_leaks'), 1;
+    }
   }
 
   for (keys %$base_collection) {
@@ -288,8 +313,12 @@ my @compose_ns_classes;
     sub { shift->result_source },
     sub { shift->schema },
     sub { shift->clone },
-    sub { shift->resultset('Artist') },
+    sub { shift->resultset('CD') },
     sub { shift->next },
+    sub { shift->artist },
+    sub { shift->search_related('cds') },
+    sub { shift->next },
+    sub { shift->search_related('artist') },
     sub { shift->result_source },
     sub { shift->resultset },
     sub { shift->create({ name => 'detached' }) },
@@ -367,6 +396,22 @@ for my $moniker ( keys %{DBICTest::Schema->source_registrations || {}} ) {
   delete $weak_registry->{DBICTest::Schema->source($moniker)};
 }
 
+# FIXME !!!
+# There is an actual strong circular reference taking place here, but because
+# half of it is in XS no leaktracer sees it, and Devel::FindRef is equally
+# stumped when trying to trace the origin. The problem is:
+#
+# $cond_object --> result_source --> schema --> storage --> $dbh --> {cached_kids}
+#          ^                                                           /
+#           \-------- bound value on prepared/cached STH  <-----------/
+#
+TODO: {
+  local $TODO = 'Not sure how to fix this yet, an entanglment could be an option';
+  my $r = $weak_registry->{'basic leaky_resultset_cond'}{weakref};
+  ok(! defined $r, 'We no longer leak!')
+    or $r->result_source(undef);
+}
+
 for my $slot (sort keys %$weak_registry) {
 
   ok (! defined $weak_registry->{$slot}{weakref}, "No leaks of $slot") or do {