validate filter_vars (#1772)

CHANGELOG.md

@@ -42,6 +42,7 @@
 * Fixed xarray related tests. ([1726](https://github.com/arviz-devs/arviz/pull/1726))
 * Fix Bokeh deprecation warnings ([1657](https://github.com/arviz-devs/arviz/pull/1657))
 * Fix credible inteval percentage in legend in `plot_loo_pit` ([1745](https://github.com/arviz-devs/arviz/pull/1745))
+* Arguments `filter_vars` and `filter_groups` now raise `ValueError` if illegal arguments are passed ([1772](https://github.com/arviz-devs/arviz/pull/1772))
 
 ### Deprecation
 * Deprecated `index_origin` and `order` arguments in `az.summary` ([1201](https://github.com/arviz-devs/arviz/pull/1201))

arviz/data/inference_data.py

@@ -1450,6 +1450,11 @@ def _group_names(
         -------
         groups: list
         """
+        if filter_groups not in {None, "like", "regex"}:
+            raise ValueError(
+                f"'filter_groups' can only be None, 'like', or 'regex', got: '{filter_groups}'"
+            )
+
         all_groups = self._groups_all
         if groups is None:
             return all_groups

arviz/tests/base_tests/test_data.py

@@ -509,6 +509,15 @@ def test_group_names(self, args_res):
         group_names = idata._group_names(*args)  # pylint: disable=protected-access
         assert np.all([name in result for name in group_names])
 
+    def test_group_names_invalid_args(self):
+        ds = dict_to_dataset({"a": np.random.normal(size=(3, 10))})
+        idata = InferenceData(posterior=(ds, ds))
+        msg = r"^\'filter_groups\' can only be None, \'like\', or \'regex\', got: 'foo'$"
+        with pytest.raises(ValueError, match=msg):
+            idata._group_names(  # pylint: disable=protected-access
+                ("posterior",), filter_groups="foo"
+            )
+
     @pytest.mark.parametrize("inplace", [False, True])
     def test_isel(self, data_random, inplace):
         idata = data_random

arviz/tests/base_tests/test_utils.py

@@ -101,6 +101,15 @@ def test_var_names_filter(var_args):
     assert _var_names(var_names, data, filter_vars) == expected
 
 
+def test_var_names_filter_invalid_argument():
+    """Check invalid argument raises."""
+    samples = np.random.randn(10)
+    data = dict_to_dataset({"alpha": samples})
+    msg = r"^\'filter_vars\' can only be None, \'like\', or \'regex\', got: 'foo'$"
+    with pytest.raises(ValueError, match=msg):
+        assert _var_names(["alpha"], data, filter_vars="foo")
+
+
 def test_subset_list_negation_not_found():
     """Check there is a warning if negation pattern is ignored"""
     names = ["mu", "theta"]

arviz/utils.py

@@ -34,6 +34,11 @@ def _var_names(var_names, data, filter_vars=None):
     -------
     var_name: list or None
     """
+    if filter_vars not in {None, "like", "regex"}:
+        raise ValueError(
+            f"'filter_vars' can only be None, 'like', or 'regex', got: '{filter_vars}'"
+        )
+
     if var_names is not None:
         if isinstance(data, (list, tuple)):
             all_vars = []