From 9b57973ff2025635d0254e1c7b2713c8feaffde6 Mon Sep 17 00:00:00 2001
From: Jonas Hartmann <jh@ht-studios.de>
Date: Sat, 30 Apr 2016 03:17:17 +0000
Subject: [PATCH] fixes unknown hash index errors when working with unique and
 overlapping foreign keys in postgres

---
 src/Database/Schema/Table.php | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/Database/Schema/Table.php b/src/Database/Schema/Table.php
index d6afb6f7ba4..44a9e20c7b8 100644
--- a/src/Database/Schema/Table.php
+++ b/src/Database/Schema/Table.php
@@ -603,10 +603,12 @@ public function addConstraint($name, $attrs)
                     $attrs['columns']
                 ));
 
-                $this->_constraints[$name]['references'][1] = array_unique(array_merge(
-                    (array)$this->_constraints[$name]['references'][1],
-                    [$attrs['references'][1]]
-                ));
+                if (isset($this->_constraints[$name]['references'])) {
+                    $this->_constraints[$name]['references'][1] = array_unique(array_merge(
+                        (array)$this->_constraints[$name]['references'][1],
+                        [$attrs['references'][1]]
+                    ));
+                }
                 return $this;
             }
         } else {