FIX latching logic simplified

jklymak · jklymak · commit 7057ddf5afd0 · 2020-04-20T13:34:34.000-07:00
diff --git a/lib/matplotlib/dates.py b/lib/matplotlib/dates.py
@@ -222,16 +222,13 @@ def _get_rc_timezone():
 
 # default epoch: passed to np.datetime64...
 _epoch = None
-_epoch_used = False
 
 
 def _reset_epoch_test_example():
-    """Reset the Matplotlib date epoch to its rcParams value."""
+    """Reset the Matplotlib date epoch so it can be set again."""
     global _epoch
-    global _epoch_used
 
-    _epoch_used = False
-    _epoch = matplotlib.rcParams['date.epoch']
+    _epoch = None
 
 
 def set_epoch(epoch):
@@ -260,8 +257,7 @@ def set_epoch(epoch):
 
     """
     global _epoch
-    global _epoch_used
-    if _epoch_used:
+    if _epoch is not None:
         raise RuntimeError('set_epoch must be called before dates plotted.')
     _epoch = epoch
 
@@ -276,13 +272,9 @@ def get_epoch():
         String for the epoch (parsable by `numpy.datetime64`)
     """
     global _epoch
-    global _epoch_used
 
     if _epoch is None:
         _epoch = matplotlib.rcParams['date.epoch']
-    # if get_epoch is called, then set_epoch can no longer be called.
-    # _epoch_used is the latch for checking this.
-    _epoch_used = True
     return _epoch
 
 
