Confusion about NeptuneLogger.save_dir implementation
In the docstring it says the save_dir is None, but then why does it return a path? Should we change either the docstring, or the implementation here?

  
    
      pytorch-lightning/pytorch_lightning/loggers/neptune.py
    
    
        Lines 516 to 524
      in
      9d8faec
    
  
  
    

        
          
               @property 
        

        
          
               def save_dir(self) -> Optional[str]: 
        

        
          
                   """Gets the save directory of the experiment which in this case is ``None`` because Neptune does not save 
        

        
          
                   locally. 
        

        
          
            
        

        
          
                   Returns: 
        

        
          
                       the root directory where experiment logs get saved 
        

        
          
                   """ 
        

        
          
                   return os.path.join(os.getcwd(), ".neptune")
Hi @daniellepintz
Prince Canuma here, a Data Scientist at Neptune.ai
I will let the engineering team know about this,
By default, Neptune will create a '.neptune' folder inside the current working directory. In the case of #6867 it changes the model checkpoint path to be '.neptune' folder in case the user doesn't define his own path using ModelCheckpointCallback() for example.
Check this commit: 5ac80ec

But still, a bit confused because I thought Neptune doesn't save anything locally.

Neptune uses the '.neptune' folder to store metadata temporarily. For example, you track a run in offline mode or there is a network connectivity issue in which case neptune also automatically switches to offline mode and save the data to disk. Later you can synchronize the locally stored metadata with the servers using the neptune sync CLI command.
Docs:
https://docs.neptune.ai/api-reference/command-line-interface#neptune
https://docs.neptune.ai/api-reference/command-line-interface#neptune-sync