Add prefix check to index generation.

src/DominionEnterprises/Mongo/Queue.php

@@ -104,6 +104,7 @@ public function ensureGetIndex(array $beforeSort = array(), array $afterSort = a
 
     /**
      * Ensure an index for the count() method.
+     * Is a no-op if the generated index is a prefix of an existing one. If you have a similar ensureGetIndex call, call it first.
      *
      * @param array $fields fields in count() call to index in same format as \MongoCollection::ensureIndex()
      * @param bool $includeRunning whether to include the running field in the index
@@ -425,6 +426,7 @@ public function send(array $payload, $earliestGet = 0, $priority = 0.0)
 
     /**
      * Ensure index of correct specification and a unique name whether the specification or name already exist or not.
+     * Will not create index if $index is a prefix of an existing index
      *
      * @param array $index index to create in same format as \MongoCollection::ensureIndex()
      *
@@ -434,6 +436,14 @@ public function send(array $payload, $earliestGet = 0, $priority = 0.0)
      */
     private function _ensureIndex(array $index)
     {
+        //if $index is a prefix of any existing index we are good
+        foreach ($this->_collection->getIndexInfo() as $existingIndex) {
+            $slice = array_slice($existingIndex['key'], 0, count($index), true);
+            if ($slice === $index) {
+                return;
+            }
+        }
+
         for ($i = 0; $i < 5; ++$i) {
             for ($name = uniqid(); strlen($name) > 0; $name = substr($name, 0, -1)) {
                 //creating an index with same name and different spec does nothing.

tests/DominionEnterprises/Mongo/QueueTest.php

@@ -134,6 +134,21 @@ public function ensureCountIndex()
         $this->assertSame($expectedTwo, $resultTwo[2]['key']);
     }
 
+    /**
+     * @test
+     */
+    public function ensureCountIndexWithPrefixOfPrevious()
+    {
+        $this->_queue->ensureCountIndex(array('type' => 1, 'boo' => -1), false);
+        $this->_queue->ensureCountIndex(array('type' => 1), false);
+
+        $this->assertSame(2, count($this->_collection->getIndexInfo()));
+
+        $expected = array('payload.type' => 1, 'payload.boo' => -1);
+        $result = $this->_collection->getIndexInfo();
+        $this->assertSame($expected, $result[1]['key']);
+    }
+
     /**
      * @test
      * @expectedException \InvalidArgumentException