From 1d91ff6ff2a9499820ad690f8bd91f516ddec72e Mon Sep 17 00:00:00 2001
From: Dan Allan <dallan@bnl.gov>
Date: Thu, 18 Mar 2021 15:35:21 -0400
Subject: [PATCH] Fix path where num_images is undefined.

---
 databroker/core.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/databroker/core.py b/databroker/core.py
index 2cd9bdb6f..de0d1a432 100644
--- a/databroker/core.py
+++ b/databroker/core.py
@@ -2119,6 +2119,8 @@ def extract_shape(descriptor, key, resource=None):
                     break
             else:
                 num_images = -1
+    else:
+        num_images = -1
     # Work around bug in https://github.com/bluesky/ophyd/pull/746
     # Broken ophyd reports (x, y, 0). We want (num_images, y, x).
     if len(data_key['shape']) == 3 and data_key['shape'][-1] == 0: