Resolve: 'DummyExperiment' object does not support item assignment

CHANGELOG.md

@@ -240,7 +240,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Fixed a bug that caused incorrect batch indices to be passed to the `BasePredictionWriter` hooks when using a dataloader with `num_workers > 0` ([#10870](https://github.com/PyTorchLightning/pytorch-lightning/pull/10870))
 
 
--
+- Fixed an issue with item assignment on the logger on rank > 0 for those who support it ([#10917](https://github.com/PyTorchLightning/pytorch-lightning/pull/10917))
 
 
 

pytorch_lightning/loggers/base.py

@@ -474,6 +474,9 @@ def __getitem__(self, idx) -> "DummyExperiment":
         # enables self.logger.experiment[0].add_image(...)
         return self
 
+    def __setitem__(self, *args, **kwargs) -> None:
+        pass
+
 
 class DummyLogger(LightningLoggerBase):
     """Dummy logger for internal use.

tests/loggers/test_base.py

@@ -241,6 +241,13 @@ def test_dummylogger_noop_method_calls():
     logger.log_metrics("1", 2, three="three")
 
 
+def test_dummyexperiment_support_item_assignment():
+    """Test that the DummyExperiment supports item assignment."""
+    experiment = DummyExperiment()
+    experiment["variable"] = "value"
+    assert experiment["variable"] != "value"  # this is only a stateless mock experiment
+
+
 def test_np_sanitization():
     class CustomParamsLogger(CustomLogger):
         def __init__(self):