From f23dfa1ae527fa3029573b8ca5e570135b6f11c3 Mon Sep 17 00:00:00 2001
From: Ken Lauer <klauer@slac.stanford.edu>
Date: Tue, 8 Aug 2023 14:09:14 -0700
Subject: [PATCH] FIX: patch over issue 565

---
 .../upcoming_release_notes/565-poslimits.rst  | 23 +++++++++++++++++++
 typhos/positioner.py                          |  6 ++++-
 2 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 docs/source/upcoming_release_notes/565-poslimits.rst

diff --git a/docs/source/upcoming_release_notes/565-poslimits.rst b/docs/source/upcoming_release_notes/565-poslimits.rst
new file mode 100644
index 00000000..f48a7553
--- /dev/null
+++ b/docs/source/upcoming_release_notes/565-poslimits.rst
@@ -0,0 +1,23 @@
+565 poslimits
+#############
+
+API Changes
+-----------
+- N/A
+
+Features
+--------
+- N/A
+
+Bugfixes
+--------
+- Avoid uncaught ``TypeError`` when ``None`` is present in a positioner
+  ``.limits``.
+
+Maintenance
+-----------
+- N/A
+
+Contributors
+------------
+- klauer
diff --git a/typhos/positioner.py b/typhos/positioner.py
index 83a5b265..887075b4 100644
--- a/typhos/positioner.py
+++ b/typhos/positioner.py
@@ -314,7 +314,11 @@ def _link_limits_by_limits_attr(self):
         except Exception:
             ...
         else:
-            if low_limit < high_limit:
+            if low_limit is None or high_limit is None:
+                # Some devices may erroneously report `None` limits.
+                # TyphosPositioner will hide the limit labels in this scenario.
+                ...
+            elif low_limit < high_limit:
                 self.ui.low_limit.setText(str(low_limit))
                 self.ui.high_limit.setText(str(high_limit))
                 return