Raise AttributeError in lightning_getattr and lightning_setattr when attribute not found (#6024)

* Empty commit

* Raise AttributeError instead of ValueError

* Make functions private

* Update tests

* Add match string

* Apply suggestions from code review

Co-authored-by: Adrian Wälchli <aedu.waelchli@gmail.com>

* lightning to Lightning

Co-authored-by: Adrian Wälchli <aedu.waelchli@gmail.com>

pytorch_lightning/utilities/parsing.py

@@ -196,9 +196,11 @@ class AttributeDict(Dict):
         return out
 
 
-def lightning_get_all_attr_holders(model, attribute):
-    """ Special attribute finding for lightning.  Gets all of the objects or dicts that holds attribute.
-            Checks for attribute in model namespace, the old hparams namespace/dict, and the datamodule. """
+def _lightning_get_all_attr_holders(model, attribute):
+    """
+    Special attribute finding for Lightning. Gets all of the objects or dicts that holds attribute.
+    Checks for attribute in model namespace, the old hparams namespace/dict, and the datamodule.
+    """
     trainer = getattr(model, 'trainer', None)
 
     holders = []
@@ -219,13 +221,13 @@ def lightning_get_all_attr_holders(model, attribute):
     return holders
 
 
-def lightning_get_first_attr_holder(model, attribute):
+def _lightning_get_first_attr_holder(model, attribute):
     """
-    Special attribute finding for lightning.  Gets the object or dict that holds attribute, or None.
-     Checks for attribute in model namespace, the old hparams namespace/dict, and the datamodule,
-     returns the last one that has it.
-     """
-    holders = lightning_get_all_attr_holders(model, attribute)
+    Special attribute finding for Lightning.  Gets the object or dict that holds attribute, or None.
+    Checks for attribute in model namespace, the old hparams namespace/dict, and the datamodule,
+    returns the last one that has it.
+    """
+    holders = _lightning_get_all_attr_holders(model, attribute)
     if len(holders) == 0:
         return None
     # using the last holder to preserve backwards compatibility
@@ -233,17 +235,26 @@ def lightning_get_first_attr_holder(model, attribute):
 
 
 def lightning_hasattr(model, attribute):
-    """ Special hasattr for lightning. Checks for attribute in model namespace,
-        the old hparams namespace/dict, and the datamodule. """
-    return lightning_get_first_attr_holder(model, attribute) is not None
+    """
+    Special hasattr for Lightning. Checks for attribute in model namespace,
+    the old hparams namespace/dict, and the datamodule.
+    """
+    return _lightning_get_first_attr_holder(model, attribute) is not None
 
 
 def lightning_getattr(model, attribute):
-    """ Special getattr for lightning. Checks for attribute in model namespace,
-        the old hparams namespace/dict, and the datamodule. """
-    holder = lightning_get_first_attr_holder(model, attribute)
+    """
+    Special getattr for Lightning. Checks for attribute in model namespace,
+    the old hparams namespace/dict, and the datamodule.
+
+    Raises:
+        AttributeError:
+            If ``model`` doesn't have ``attribute`` in any of
+            model namespace, the hparams namespace/dict, and the datamodule.
+    """
+    holder = _lightning_get_first_attr_holder(model, attribute)
     if holder is None:
-        raise ValueError(
+        raise AttributeError(
             f'{attribute} is neither stored in the model namespace'
             ' nor the `hparams` namespace/dict, nor the datamodule.'
         )
@@ -254,13 +265,19 @@ def lightning_getattr(model, attribute):
 
 
 def lightning_setattr(model, attribute, value):
-    """ Special setattr for lightning. Checks for attribute in model namespace
-        and the old hparams namespace/dict.
-        Will also set the attribute on datamodule, if it exists.
     """
-    holders = lightning_get_all_attr_holders(model, attribute)
+    Special setattr for Lightning. Checks for attribute in model namespace
+    and the old hparams namespace/dict.
+    Will also set the attribute on datamodule, if it exists.
+
+    Raises:
+        AttributeError:
+            If ``model`` doesn't have ``attribute`` in any of
+            model namespace, the hparams namespace/dict, and the datamodule.
+    """
+    holders = _lightning_get_all_attr_holders(model, attribute)
     if len(holders) == 0:
-        raise ValueError(
+        raise AttributeError(
             f'{attribute} is neither stored in the model namespace'
             ' nor the `hparams` namespace/dict, nor the datamodule.'
         )

tests/utilities/test_parsing.py

@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import pytest
 
 from pytorch_lightning.utilities.parsing import lightning_getattr, lightning_hasattr, lightning_setattr
 
@@ -74,8 +75,8 @@ def _get_test_cases():
 
 
 def test_lightning_hasattr(tmpdir):
-    """ Test that the lightning_hasattr works in all cases"""
-    model1, model2, model3, model4, model5, model6, model7 = _get_test_cases()
+    """Test that the lightning_hasattr works in all cases"""
+    model1, model2, model3, model4, model5, model6, model7 = models = _get_test_cases()
     assert lightning_hasattr(model1, 'learning_rate'), \
         'lightning_hasattr failed to find namespace variable'
     assert lightning_hasattr(model2, 'learning_rate'), \
@@ -91,9 +92,12 @@ def test_lightning_hasattr(tmpdir):
     assert lightning_hasattr(model7, 'batch_size'), \
         'lightning_hasattr failed to find batch_size in hparams w/ datamodule present'
 
+    for m in models:
+        assert not lightning_hasattr(m, "this_attr_not_exist")
+
 
 def test_lightning_getattr(tmpdir):
-    """ Test that the lightning_getattr works in all cases"""
+    """Test that the lightning_getattr works in all cases"""
     models = _get_test_cases()
     for i, m in enumerate(models[:3]):
         value = lightning_getattr(m, 'learning_rate')
@@ -107,9 +111,16 @@ def test_lightning_getattr(tmpdir):
     assert lightning_getattr(model7, 'batch_size') == 8, \
         'batch_size not correctly extracted'
 
+    for m in models:
+        with pytest.raises(
+                AttributeError,
+                match="is neither stored in the model namespace nor the `hparams` namespace/dict, nor the datamodule."
+        ):
+            lightning_getattr(m, "this_attr_not_exist")
+
 
 def test_lightning_setattr(tmpdir):
-    """ Test that the lightning_setattr works in all cases"""
+    """Test that the lightning_setattr works in all cases"""
     models = _get_test_cases()
     for m in models[:3]:
         lightning_setattr(m, 'learning_rate', 10)
@@ -126,3 +137,10 @@ def test_lightning_setattr(tmpdir):
         'batch_size not correctly set'
     assert lightning_getattr(model7, 'batch_size') == 128, \
         'batch_size not correctly set'
+
+    for m in models:
+        with pytest.raises(
+                AttributeError,
+                match="is neither stored in the model namespace nor the `hparams` namespace/dict, nor the datamodule."
+        ):
+            lightning_setattr(m, "this_attr_not_exist", None)