From 2d6203d902b1649935261d77bb4ecd1bc2d2c3b4 Mon Sep 17 00:00:00 2001
From: Maxime Beauchemin <maximebeauchemin@gmail.com>
Date: Mon, 9 Oct 2017 20:59:11 -0700
Subject: [PATCH] [bugfix] empty From date filter NoneType error (#3633)

Error "AttributeError: 'NoneType' object has no attribute 'split'" is
fired.
---
 superset/viz.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/superset/viz.py b/superset/viz.py
index 953d815768368..a800bc0375a88 100644
--- a/superset/viz.py
+++ b/superset/viz.py
@@ -158,10 +158,11 @@ def query_obj(self):
         until = form_data.get("until", "now")
 
         # Backward compatibility hack
-        since_words = since.split(' ')
-        grains = ['days', 'years', 'hours', 'day', 'year', 'weeks']
-        if (len(since_words) == 2 and since_words[1] in grains):
-            since += ' ago'
+        if since:
+            since_words = since.split(' ')
+            grains = ['days', 'years', 'hours', 'day', 'year', 'weeks']
+            if (len(since_words) == 2 and since_words[1] in grains):
+                since += ' ago'
 
         from_dttm = utils.parse_human_datetime(since)