1 files changed, 46 insertions, 1 deletions

diff --git a/Bugzilla/Bug.pm b/Bugzilla/Bug.pm
index fd28b5b82..1e418aa18 100644
--- a/Bugzilla/Bug.pm
+++ b/Bugzilla/Bug.pm
@@ -25,6 +25,7 @@
 #                 Max Kanat-Alexander <mkanat@bugzilla.org>
 #                 Frédéric Buclin <LpSolit@gmail.com>
 #                 Lance Larsh <lance.larsh@oracle.com>
+#                 Elliotte Martin <elliotte_martin@yahoo.com>
 
 package Bugzilla::Bug;
 
@@ -1761,7 +1762,42 @@ sub _check_select_field {
 sub _check_bugid_field {
     my ($invocant, $value, $field) = @_;
     return undef if !$value;
-    return $invocant->check($value, $field)->id;
+    
+    # check that the value is a valid, visible bug id
+    my $checked_id = $invocant->check($value, $field)->id;
+    
+    # check for loop (can't have a loop if this is a new bug)
+    if (ref $invocant) {
+        _check_relationship_loop($field, $invocant->bug_id, $checked_id);
+    }
+
+    return $checked_id;
+}
+
+sub _check_relationship_loop {
+    # Generates a dependency tree for a given bug.  Calls itself recursively
+    # to generate sub-trees for the bug's dependencies.
+    my ($field, $bug_id, $dep_id, $ids) = @_;
+
+    # Don't do anything if this bug doesn't have any dependencies.
+    return unless defined($dep_id);
+
+    # Check whether we have seen this bug yet
+    $ids = {} unless defined $ids;
+    $ids->{$bug_id} = 1;
+    if ($ids->{$dep_id}) {
+        ThrowUserError("relationship_loop_single", {
+            'bug_id' => $bug_id,
+            'dep_id' => $dep_id,
+            'field_name' => $field});
+    }
+    
+    # Get this dependency's record from the database
+    my $dbh = Bugzilla->dbh;
+    my $next_dep_id = $dbh->selectrow_array(
+        "SELECT $field FROM bugs WHERE bug_id = ?", undef, $dep_id);
+
+    _check_relationship_loop($field, $dep_id, $next_dep_id, $ids);
 }
 
 #####################################################################
@@ -2553,6 +2589,15 @@ sub blocked {
 # Even bugs in an error state always have a bug_id.
 sub bug_id { $_[0]->{'bug_id'}; }
 
+sub related_bugs {
+    my ($self, $relationship) = @_;
+    return [] if $self->{'error'};
+
+    my $field_name = $relationship->name;
+    $self->{'related_bugs'}->{$field_name} ||= $self->match({$field_name => $self->id});
+    return $self->{'related_bugs'}->{$field_name}; 
+}
+
 sub cc {
     my ($self) = @_;
     return $self->{'cc'} if exists $self->{'cc'};