Return only unique names/versions for LoggerCollection (#10976)

Co-authored-by: Rohit Gupta <rohitgr1998@gmail.com>

CHANGELOG.md

@@ -112,6 +112,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Changed the name of the temporary checkpoint that the `DDPSpawnPlugin` and related plugins save ([#10934](https://github.com/PyTorchLightning/pytorch-lightning/pull/10934))
 
 
+- `LoggerCollection` returns only unique logger names and versions ([#10976](https://github.com/PyTorchLightning/pytorch-lightning/pull/10976))
+
+
 - Redesigned process creation for spawn-based plugins (`DDPSpawnPlugin`, `TPUSpawnPlugin`, etc.) ([#10896](https://github.com/PyTorchLightning/pytorch-lightning/pull/10896))
     * All spawn-based plugins now spawn processes immediately upon calling `Trainer.{fit,validate,test,predict}`
     * The hooks/callbacks `prepare_data`, `setup`, `configure_sharded_model` and `teardown` now run under initialized process group for spawn-based plugins just like their non-spawn counterparts

pytorch_lightning/loggers/base.py

@@ -452,13 +452,15 @@ class LoggerCollection(LightningLoggerBase):
 
     @property
     def name(self) -> str:
-        """Returns the experiment names for all the loggers in the logger collection joined by an underscore."""
-        return "_".join(str(logger.name) for logger in self._logger_iterable)
+        """Returns the unique experiment names for all the loggers in the logger collection joined by an
+        underscore."""
+        return "_".join(dict.fromkeys(str(logger.name) for logger in self._logger_iterable))
 
     @property
     def version(self) -> str:
-        """Returns the experiment versions for all the loggers in the logger collection joined by an underscore."""
-        return "_".join(str(logger.version) for logger in self._logger_iterable)
+        """Returns the unique experiment versions for all the loggers in the logger collection joined by an
+        underscore."""
+        return "_".join(dict.fromkeys(str(logger.version) for logger in self._logger_iterable))
 
 
 class DummyExperiment:

tests/loggers/test_base.py

@@ -56,9 +56,44 @@ def test_logger_collection():
     mock2.finalize.assert_called_once()
 
 
+def test_logger_collection_unique_names():
+    unique_name = "name1"
+    logger1 = CustomLogger(name=unique_name)
+    logger2 = CustomLogger(name=unique_name)
+
+    logger = LoggerCollection([logger1, logger2])
+
+    assert logger.name == unique_name
+
+
+def test_logger_collection_names_order():
+    loggers = [CustomLogger(name=n) for n in ("name1", "name2", "name1", "name3")]
+    logger = LoggerCollection(loggers)
+    assert logger.name == f"{loggers[0].name}_{loggers[1].name}_{loggers[3].name}"
+
+
+def test_logger_collection_unique_versions():
+    unique_version = "1"
+    logger1 = CustomLogger(version=unique_version)
+    logger2 = CustomLogger(version=unique_version)
+
+    logger = LoggerCollection([logger1, logger2])
+
+    assert logger.version == unique_version
+
+
+def test_logger_collection_versions_order():
+    loggers = [CustomLogger(version=v) for v in ("1", "2", "1", "3")]
+    logger = LoggerCollection(loggers)
+    assert logger.version == f"{loggers[0].version}_{loggers[1].version}_{loggers[3].version}"
+
+
 class CustomLogger(LightningLoggerBase):
-    def __init__(self):
+    def __init__(self, experiment: str = "test", name: str = "name", version: str = "1"):
         super().__init__()
+        self._experiment = experiment
+        self._name = name
+        self._version = version
         self.hparams_logged = None
         self.metrics_logged = {}
         self.finalized = False
@@ -66,7 +101,7 @@ class CustomLogger(LightningLoggerBase):
 
     @property
     def experiment(self):
-        return "test"
+        return self._experiment
 
     @rank_zero_only
     def log_hyperparams(self, params):
@@ -88,11 +123,11 @@ class CustomLogger(LightningLoggerBase):
 
     @property
     def name(self):
-        return "name"
+        return self._name
 
     @property
     def version(self):
-        return "1"
+        return self._version
 
     def after_save_checkpoint(self, checkpoint_callback):
         self.after_save_checkpoint_called = True