From 118a2aae66b608eb3eef318fe4e113303de121fc Mon Sep 17 00:00:00 2001
From: Duncan Macleod <duncan.macleod@ligo.org>
Date: Thu, 8 Mar 2018 04:35:23 -0800
Subject: [PATCH] data.find_frames: fixed IndexError for no frames

---
 omicron/data.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/omicron/data.py b/omicron/data.py
index 655f875..efc1291 100644
--- a/omicron/data.py
+++ b/omicron/data.py
@@ -208,11 +208,14 @@ def find_frames(obs, frametype, start, end, connection=None, **kwargs):
         # use latest frame to find more recent frames that aren't in
         # datafind yet, this is quite hacky, and isn't guaranteed to
         # work at any point, but it shouldn't break anything
-        latest = cache[-1]
+        try:
+            latest = cache[-1]
+        except IndexError:  # no frames
+            return cache
         try:
             ngps = len(re_gwf_gps_epoch.search(
                 os.path.dirname(latest.path)).groupdict()['gpsepoch'])
-        except AttributeError:
+        except AttributeError:  # no match
             pass
         else:
             while True: