No warnings by default

pandas/plotting/_compat.py

@@ -73,11 +73,3 @@ def _mpl_ge_2_1_0():
         return matplotlib.__version__ >= LooseVersion('2.1')
     except ImportError:
         return False
-
-
-def _mpl_ge_2_2_0():
-    try:
-        import matplotlib
-        return matplotlib.__version__ > LooseVersion('2.1')
-    except ImportError:
-        return False

pandas/plotting/_converter.py

@@ -35,7 +35,6 @@
 from pandas.core.indexes.period import Period, PeriodIndex
 
 from pandas.plotting._compat import _mpl_le_2_0_0
-from pandas.plotting._compat import _mpl_ge_2_2_0
 
 # constants
 HOURS_PER_DAY = 24.
@@ -47,8 +46,8 @@
 
 MUSEC_PER_DAY = 1e6 * SEC_PER_DAY
 
-_WARN = True
-_mpl_units = {}
+_WARN = True  # Global for whether pandas has registered the units explicitly
+_mpl_units = {}  # Cache for units overwritten by us
 
 
 def get_pairs():
@@ -60,12 +59,10 @@ def get_pairs():
         (pydt.time, TimeConverter),
         (np.datetime64, DatetimeConverter),
     ]
-    if _mpl_ge_2_2_0():
-        pairs = pairs[:2]
     return pairs
 
 
-def register(warn=False):
+def register(explicit=False):
     """Register Pandas Formatters and Converters with matplotlib
 
     This function modifies the global ``matplotlib.units.registry``
@@ -85,11 +82,10 @@ def register(warn=False):
     # Renamed in pandas.plotting.__init__
     global _WARN
 
-    if not warn:
+    if explicit:
         _WARN = False
 
     pairs = get_pairs()
-    print(pairs)
     for type_, cls in pairs:
         converter = cls()
         if type_ in units.registry:

pandas/plotting/_core.py

@@ -47,7 +47,7 @@
     pass
 else:
     if get_option('plotting.matplotlib.register_converters'):
-        _converter.register(warn=True)
+        _converter.register(explicit=True)
 
 
 def _get_standard_kind(kind):

pandas/tests/plotting/test_converter.py

@@ -109,7 +109,7 @@ def test_registry_resets(self):
             units.registry[date] = date_converter
 
             register_matplotlib_converters()
-            assert not units.registry[date] is date_converter
+            assert units.registry[date] is date_converter
             deregister_matplotlib_converters()
             assert units.registry[date] is date_converter