fix infer_freq not working for H freq with DST (fix pandas-dev#39556 and pandas-dev#8772)

sdementen · web-flow · commit 774571509bb2 · 2021-02-07T12:15:40.000+01:00
Fixes the issues pandas-dev#39556 and pandas-dev#8772 by ensuring that the check for delta being a multiple of a frequency also checks the delta is not 0 (which is a multiple of any number).
diff --git a/pandas/tseries/frequencies.py b/pandas/tseries/frequencies.py
@@ -414,7 +414,7 @@ def _infer_daily_rule(self):
 
 
 def _is_multiple(us, mult: int) -> bool:
-    return us % mult == 0
+    return us and (us % mult == 0)
 
 
 def _maybe_add_count(base: str, count: float) -> str:
