Zend_Json::decode null or empty string throw Zend_Json_Exception on PHP7 (#678)

library/Zend/Json.php

@@ -73,6 +73,9 @@ class Zend_Json
      */
     public static function decode($encodedValue, $objectDecodeType = Zend_Json::TYPE_ARRAY)
     {
+        if (in_array($encodedValue, array(null, ''))) {
+            return null;
+        }
         $encodedValue = (string) $encodedValue;
         if (function_exists('json_decode') && self::$useBuiltinEncoderDecoder !== true) {
             $decode = json_decode($encodedValue, $objectDecodeType);

tests/Zend/JsonTest.php

@@ -922,6 +922,40 @@ public function testWillDecodeStructureWithEmptyKeyToObjectProperly()
         $this->assertEquals('test', $object->_empty_);
     }
 
+    /**
+     * Decoding null should return null
+     */
+    public function testWillDecodeNullToNull()
+    {
+        $this->assertNull(Zend_Json::decode(null));
+    }
+
+    /**
+     * Decoding null should return null
+     */
+    public function testWillDecodeWithBuiltinNullToNull()
+    {
+        Zend_Json::$useBuiltinEncoderDecoder = true;
+        $this->assertNull(Zend_Json::decode(null));
+    }
+
+    /**
+     * Decoding empty string should return null
+     */
+    public function testWillDecodeEmptyStringToNull()
+    {
+        $this->assertNull(Zend_Json::decode(''));
+    }
+
+    /**
+     * Decoding empty string should return null
+     */
+    public function testWillDecodeWithBuiltinEmptyStringToNull()
+    {
+        Zend_Json::$useBuiltinEncoderDecoder = true;
+        $this->assertNull(Zend_Json::decode(''));
+    }
+
 }
 
 /**