Unify attribute finding logic, fix not using dataloader when hparams …

…present (#4559)

* Rebase onto master

* indent fix

* Remove duplicated logic

* Use single return

* Remove extra else

* add `__contains__` to TestHparamsNamespace to fix tests

* Fix lightning_setattr to set all valid attributes

* update doc

* better names

* fix holder order preference

* tests for new behavior

* Comment about using the last holder

Co-authored-by: Jirka Borovec <Borda@users.noreply.github.com>
Co-authored-by: Sean Naren <sean.narenthiran@gmail.com>

(cherry picked from commit eee3b1a)

pytorch_lightning/utilities/parsing.py

@@ -196,76 +196,70 @@ def __repr__(self):
         return out
 
 
-def lightning_hasattr(model, attribute):
-    """ Special hasattr for lightning. 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)
 
-    attr = False
+    holders = []
+
     # Check if attribute in model
     if hasattr(model, attribute):
-        attr = True
+        holders.append(model)
+
     # Check if attribute in model.hparams, either namespace or dict
-    elif hasattr(model, 'hparams'):
-        if isinstance(model.hparams, dict):
-            attr = attribute in model.hparams
-        else:
-            attr = hasattr(model.hparams, attribute)
+    if hasattr(model, 'hparams'):
+        if attribute in model.hparams:
+            holders.append(model.hparams)
+
     # Check if the attribute in datamodule (datamodule gets registered in Trainer)
-    if not attr and trainer is not None:
-        attr = hasattr(trainer.datamodule, attribute)
+    if trainer is not None and trainer.datamodule is not None and hasattr(trainer.datamodule, attribute):
+        holders.append(trainer.datamodule)
 
-    return attr
+    return holders
+
+
+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)
+    if len(holders) == 0:
+        return None
+    # using the last holder to preserve backwards compatibility
+    return holders[-1]
+
+
+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
 
 
 def lightning_getattr(model, attribute):
     """ Special getattr for lightning. Checks for attribute in model namespace,
         the old hparams namespace/dict, and the datamodule. """
-    trainer = getattr(model, 'trainer', None)
+    holder = lightning_get_first_attr_holder(model, attribute)
+    if holder is None:
+        raise ValueError(f'{attribute} is neither stored in the model namespace'
+                         ' nor the `hparams` namespace/dict, nor the datamodule.')
 
-    # Check if attribute in model
-    if hasattr(model, attribute):
-        attr = getattr(model, attribute)
-    # Check if attribute in model.hparams, either namespace or dict
-    elif hasattr(model, 'hparams') and isinstance(model.hparams, dict) and attribute in model.hparams:
-        attr = model.hparams[attribute]
-    elif hasattr(model, 'hparams') and hasattr(model.hparams, attribute):
-        attr = getattr(model.hparams, attribute)
-    # Check if the attribute in datamodule (datamodule gets registered in Trainer)
-    elif trainer is not None and trainer.datamodule is not None and hasattr(trainer.datamodule, attribute):
-        attr = getattr(trainer.datamodule, attribute)
-    else:
-        raise ValueError(
-            f'The {attribute} is neither stored in the model namespace nor the `hparams` namespace/dict,'
-            ' nor the datamodule.'
-        )
-    return attr
+    if isinstance(holder, dict):
+        return holder[attribute]
+    return getattr(holder, 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.
     """
-    if not lightning_hasattr(model, attribute):
-        raise ValueError(
-            f'The {attribute} is neither stored in the model namespace nor the `hparams` namespace/dict,'
-            ' nor the datamodule.'
-        )
-
-    trainer = getattr(model, 'trainer', None)
-
-    # Check if attribute in model
-    if hasattr(model, attribute):
-        setattr(model, attribute, value)
-
-    # Check if attribute in model.hparams, either namespace or dict
-    elif hasattr(model, 'hparams'):
-        if isinstance(model.hparams, dict):
-            model.hparams[attribute] = value
+    holders = lightning_get_all_attr_holders(model, attribute)
+    if len(holders) == 0:
+        raise ValueError(f'{attribute} is neither stored in the model namespace'
+                         ' nor the `hparams` namespace/dict, nor the datamodule.')
+
+    for holder in holders:
+        if isinstance(holder, dict):
+            holder[attribute] = value
         else:
-            setattr(model.hparams, attribute, value)
-
-    # Check if the attribute in datamodule (datamodule gets registered in Trainer)
-    if trainer is not None and trainer.datamodule is not None and hasattr(trainer.datamodule, attribute):
-        setattr(trainer.datamodule, attribute, value)
+            setattr(holder, attribute, value)

tests/utilities/test_parsing.py

@@ -19,6 +19,9 @@ def _get_test_cases():
     class TestHparamsNamespace:
         learning_rate = 1
 
+        def __contains__(self, item):
+            return item == "learning_rate"
+
     TestHparamsDict = {'learning_rate': 2}
 
     class TestModel1:  # test for namespace
@@ -52,12 +55,26 @@ class TestModel5:  # test for datamodule
 
     model5 = TestModel5()
 
-    return model1, model2, model3, model4, model5
+    class TestModel6:  # test for datamodule w/ hparams w/o attribute (should use datamodule)
+        trainer = Trainer
+        hparams = TestHparamsDict
+
+    model6 = TestModel6()
+
+    TestHparamsDict2 = {'batch_size': 2}
+
+    class TestModel7:  # test for datamodule w/ hparams w/ attribute (should use datamodule)
+        trainer = Trainer
+        hparams = TestHparamsDict2
+
+    model7 = TestModel7()
+
+    return model1, model2, model3, model4, model5, model6, model7
 
 
 def test_lightning_hasattr(tmpdir):
     """ Test that the lightning_hasattr works in all cases"""
-    model1, model2, model3, model4, model5 = _get_test_cases()
+    model1, model2, model3, model4, model5, model6, model7 = _get_test_cases()
     assert lightning_hasattr(model1, 'learning_rate'), \
         'lightning_hasattr failed to find namespace variable'
     assert lightning_hasattr(model2, 'learning_rate'), \
@@ -68,6 +85,10 @@ def test_lightning_hasattr(tmpdir):
         'lightning_hasattr found variable when it should not'
     assert lightning_hasattr(model5, 'batch_size'), \
         'lightning_hasattr failed to find batch_size in datamodule'
+    assert lightning_hasattr(model6, 'batch_size'), \
+        'lightning_hasattr failed to find batch_size in datamodule w/ hparams present'
+    assert lightning_hasattr(model7, 'batch_size'), \
+        'lightning_hasattr failed to find batch_size in hparams w/ datamodule present'
 
 
 def test_lightning_getattr(tmpdir):
@@ -77,9 +98,13 @@ def test_lightning_getattr(tmpdir):
         value = lightning_getattr(m, 'learning_rate')
         assert value == i, 'attribute not correctly extracted'
 
-    model5 = models[4]
+    model5, model6, model7 = models[4:]
     assert lightning_getattr(model5, 'batch_size') == 8, \
         'batch_size not correctly extracted'
+    assert lightning_getattr(model6, 'batch_size') == 8, \
+        'batch_size not correctly extracted'
+    assert lightning_getattr(model7, 'batch_size') == 8, \
+        'batch_size not correctly extracted'
 
 
 def test_lightning_setattr(tmpdir):
@@ -90,7 +115,13 @@ def test_lightning_setattr(tmpdir):
         assert lightning_getattr(m, 'learning_rate') == 10, \
             'attribute not correctly set'
 
-    model5 = models[4]
+    model5, model6, model7 = models[4:]
     lightning_setattr(model5, 'batch_size', 128)
+    lightning_setattr(model6, 'batch_size', 128)
+    lightning_setattr(model7, 'batch_size', 128)
     assert lightning_getattr(model5, 'batch_size') == 128, \
         'batch_size not correctly set'
+    assert lightning_getattr(model6, 'batch_size') == 128, \
+        'batch_size not correctly set'
+    assert lightning_getattr(model7, 'batch_size') == 128, \
+        'batch_size not correctly set'