IPython fix html rendering for DataFrame (#2837)

py-polars/polars/internals/frame.py

@@ -1242,10 +1242,19 @@ def __getattr__(self, item: Any) -> "PySeries":
         """
         Access columns as attribute.
         """
+        # it is important that we return an AttributeError here
+        # this is used by ipython to check some private
+        # `_ipython_canary_method_should_not_exist_`
+        # if we return any other error than AttributeError pretty printing
+        # will not work in notebooks.
+        # See: https://github.com/jupyter/notebook/issues/2014
+        if item.startswith("_"):
+            raise AttributeError(item)
         try:
+            warnings.warn("accessing series as Attribute of a DataFrame is deprecated")
             return pli.wrap_s(self._df.column(item))
-        except RuntimeError:
-            raise AttributeError(f"{item} not found")
+        except Exception:
+            raise AttributeError(item)
 
     def __iter__(self) -> Iterator[Any]:
         return self.get_columns().__iter__()

py-polars/tests/test_df.py

@@ -1732,7 +1732,7 @@ def test_getattr() -> None:
     df = pl.DataFrame({"a": [1.0, 2.0]})
     testing.assert_series_equal(df.a, pl.Series("a", [1.0, 2.0]))
 
-    with pytest.raises(pl.NotFoundError):
+    with pytest.raises(AttributeError):
         _ = df.b