From 1eb1cd7b64cb2ec112877f161fe1d77eb6a0cb4a Mon Sep 17 00:00:00 2001
From: Francesco Siddi <francesco.siddi@gmail.com>
Date: Sun, 12 Mar 2017 18:46:08 +0100
Subject: [PATCH] Fix for crash on extension blueprints loading

It the extension was registered with url_prefix=None, we set url_prefix to empty string so it can be added to blueprint.url_prefix.
---
 pillar/__init__.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pillar/__init__.py b/pillar/__init__.py
index a1b2c2e6..3f463b01 100644
--- a/pillar/__init__.py
+++ b/pillar/__init__.py
@@ -206,6 +206,9 @@ class PillarServer(Eve):
         # Load extension blueprint(s)
         for blueprint in pillar_extension.blueprints():
             if blueprint.url_prefix:
+                if not url_prefix:
+                    # If we registered the extension with url_prefix=None
+                    url_prefix = ''
                 blueprint_prefix = url_prefix + blueprint.url_prefix
             else:
                 blueprint_prefix = url_prefix