Don't change writeable flag on array in CategoricalComponents since t…

…his can cause issues when the underlying buffer is read-only

glue/core/component.py

@@ -435,9 +435,6 @@ def __init__(self, categorical_data, categories=None, jitter=None, units=None):
         if self._categorical_data.ndim > 1:
             raise ValueError("Categorical Data must be 1-dimensional")
 
-        # Disable changing of categories
-        self._categorical_data.setflags(write=False)
-
         self._categories = categories
         self._jitter_method = jitter
         self._is_jittered = False

glue/core/tests/test_component.py

@@ -115,6 +115,15 @@ def test_accepts_numpy(self):
         cat_comp = CategoricalComponent(self.array_data)
         assert cat_comp._categorical_data.shape == (4,)
 
+    def test_accepts_pandas(self):
+        # Regression test for a bug that caused read-only
+        # pandas DataFrame columns to cause issues
+        from pandas import DataFrame
+        df = DataFrame()
+        df['a'] = ['a', 'b', 'c']
+        print(df['a'].fillna(''), type)
+        CategoricalComponent(df['a'].fillna(''))
+
     def test_accepts_list(self):
         """Should accept a list and convert to numpy!"""
         cat_comp = CategoricalComponent(self.list_data)