Francois Gouget : testbot: Avoid reference cycles between Collections.

[Alexandre Julliard]

Module: tools
Branch: master
Commit: 86aeeb298b68529e98c8bc44ae33d0db27898fbf
URL:    http://source.winehq.org/git/tools.git/?a=commit;h=86aeeb298b68529e98c8bc44a...

Author: Francois Gouget 
Date:   Thu Dec 21 12:14:21 2017 +0100

testbot: Avoid reference cycles between Collections.

Specifically when the Collection is used for a Detailref property (e.g.
Jobs->Steps), it should not keep a reference to the parent's ScopeItems.
Reference cycles cause Perl's primitive reference-count based garbage
collector to leak memory.

Signed-off-by: Francois Gouget 
Signed-off-by: Alexandre Julliard

---

testbot/lib/ObjectModel/Collection.pm | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/testbot/lib/ObjectModel/Collection.pm b/testbot/lib/ObjectModel/Collection.pm
index c3bc438..a9ec995 100644
--- a/testbot/lib/ObjectModel/Collection.pm
+++ b/testbot/lib/ObjectModel/Collection.pm
@@ -43,6 +43,7 @@ require Exporter;
 @ISA = qw(Exporter);
 @EXPORT_OK = qw(&new &ComputeMasterKey);

+use Scalar::Util qw(weaken);
 use ObjectModel::BackEnd;
 use ObjectModel::Item;
 use ObjectModel::PropertyDescriptor;
@@ -96,6 +97,14 @@ sub new($$$$$;$$@)
               Filters             => {},
               AllScopeItems       => $AllScopeItems || {},
               Items               => undef};
+  if ($AllScopeItems)
+  {
+    # Avoid memory cycles in case Items have Detailref properties:
+    #   ParentCollection{AllScopeItems} --> ParentItem
+    #   ParentItem --DetailrefProperty--> DetailCollection
+    #   DetailCollection{AllScopeItems} == ParentCollection{AllScopeItems}
+    weaken($self->{AllScopeItems});
+  }
   $self = bless $self, $class;
   $self->_initialize(@_);
   return $self;