Avoid null index race-error during startup

2022-02-07 08:47:03 -05:00 · 2022-02-07 08:47:03 -05:00 · 1aaa382036
parent 999d3efdd7
commit 1aaa382036
1 changed files with 6 additions and 5 deletions
--- a/piker/ui/_cursor.py
+++ b/piker/ui/_cursor.py
@ -109,11 +109,12 @@ class LineDot(pg.CurvePoint):
        # first = self._plot._arrays['ohlc'][0]['index']
        # first = x[0]
        # i = index - first
-        i = index - x[0]
-        if i > 0 and i < len(y):
-            newPos = (index, y[i])
-            QtWidgets.QGraphicsItem.setPos(self, *newPos)
-            return True
+        if index:
+            i = index - x[0]
+            if i > 0 and i < len(y):
+                newPos = (index, y[i])
+                QtWidgets.QGraphicsItem.setPos(self, *newPos)
+                return True

        return False