added warning to crash (#1625)

* added warning to crash

* formatting

Co-authored-by: J. Borovec <jirka.borovec@seznam.cz>

pytorch_lightning/core/lightning.py

@@ -1162,9 +1162,9 @@ class LightningModule(ABC, GradInformation, ModelIO, ModelHooks):
 
             # native amp + lbfgs is a no go right now
             if self.trainer.use_amp and self.trainer.use_native_amp:
-                m = 'native PyTorch amp and lbfgs are not compatible. To request, please file' \
-                    'a Github issue in PyTorch and tag @mcarilli'
-                raise MisconfigurationException(m)
+                raise MisconfigurationException(
+                    'native PyTorch amp and lbfgs are not compatible.'
+                    ' To request, please file a Github issue in PyTorch and tag @mcarilli')
             optimizer.step(second_order_closure)
         else:
             if self.trainer.use_amp and self.trainer.use_native_amp:

pytorch_lightning/trainer/training_io.py

@@ -251,9 +251,11 @@ class TrainerIOMixin(ABC):
             # do the actual save
             try:
                 self._atomic_save(checkpoint, filepath)
-            except AttributeError:
+            except AttributeError as e:
                 if 'hparams' in checkpoint:
                     del checkpoint['hparams']
+                rank_zero_warn('warning, `hparams` dropped from checkpoint.'
+                               f' An attribute is not picklable {e}')
 
                 self._atomic_save(checkpoint, filepath)
 
@@ -434,9 +436,11 @@ class TrainerIOMixin(ABC):
         # TODO: fix for anything with multiprocess DP, DDP, DDP2
         try:
             self._atomic_save(checkpoint, filepath)
-        except AttributeError:
+        except AttributeError as e:
             if 'hparams' in checkpoint:
                 del checkpoint['hparams']
+            rank_zero_warn('warning, `hparams` dropped from checkpoint.'
+                           f' An attribute is not picklable {e}')
 
             self._atomic_save(checkpoint, filepath)
 

setup.cfg

@@ -18,6 +18,7 @@ exclude_lines =
     pragma: no-cover
     warnings
     pass
+    rank_zero_warn
 
 [flake8]
 # TODO: this should be 88 or 100 according PEP8