Fix missing arguments when saving hyperparams from parent class only (#9800)

* Fix missing arguments when saving hyperparams from parent class only

* fix antipattern

CHANGELOG.md

@@ -444,6 +444,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 - Fixed DeepSpeed and Lightning both calling the scheduler ([#9788](https://github.com/PyTorchLightning/pytorch-lightning/pull/9788))
 
+- Fixed missing arguments when saving hyperparameters from the parent class but not from the child class ([#9800](https://github.com/PyTorchLightning/pytorch-lightning/pull/9800))
+
 
 ## [1.4.9] - 2021-09-30
 

pytorch_lightning/utilities/parsing.py

@@ -217,7 +217,9 @@ def save_hyperparameters(
     if is_dataclass(obj):
         init_args = {f.name: getattr(obj, f.name) for f in fields(obj)}
     else:
-        init_args = get_init_args(frame)
+        init_args = {}
+        for local_args in collect_init_args(frame, []):
+            init_args.update(local_args)
     assert init_args, "failed to inspect the obj init"
 
     if ignore is not None:

tests/models/test_hparams.py

@@ -247,6 +247,13 @@ class SubClassBoringModel(CustomBoringModel):
         self.save_hyperparameters()
 
 
+class NonSavingSubClassBoringModel(CustomBoringModel):
+    any_other_loss = torch.nn.CrossEntropyLoss()
+
+    def __init__(self, *args, subclass_arg=1200, **kwargs):
+        super().__init__(*args, **kwargs)
+
+
 class SubSubClassBoringModel(SubClassBoringModel):
     pass
 
@@ -277,6 +284,7 @@ class DictConfSubClassBoringModel(SubClassBoringModel):
     [
         CustomBoringModel,
         SubClassBoringModel,
+        NonSavingSubClassBoringModel,
         SubSubClassBoringModel,
         AggSubClassBoringModel,
         UnconventionalArgsBoringModel,
@@ -296,7 +304,7 @@ def test_collect_init_arguments(tmpdir, cls):
     model = cls(batch_size=179, **extra_args)
     assert model.hparams.batch_size == 179
 
-    if isinstance(model, SubClassBoringModel):
+    if isinstance(model, (SubClassBoringModel, NonSavingSubClassBoringModel)):
         assert model.hparams.subclass_arg == 1200
 
     if isinstance(model, AggSubClassBoringModel):