Fix incorrect tuner error message (#16104)

Co-authored-by: Adrian Wälchli <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Jirka Borovec <[email protected]>
Co-authored-by: Jirka <[email protected]>
Fixes #15855

Author: 4 people

src/pytorch_lightning/tuner/tuning.py

@@ -296,8 +296,19 @@ def _check_tuner_configuration(
                 " arguments should be None, please consider setting `dataloaders` instead."
             )
 
-    if any(isinstance(cb, (BatchSizeFinder, LearningRateFinder)) for cb in trainer.callbacks):
+    configured_callbacks = []
+    for cb in trainer.callbacks:
+        if isinstance(cb, BatchSizeFinder) and trainer.auto_scale_batch_size:
+            configured_callbacks.append("BatchSizeFinder")
+        elif isinstance(cb, LearningRateFinder) and trainer.auto_lr_find:
+            configured_callbacks.append("LearningRateFinder")
+    if len(configured_callbacks) == 1:
         raise MisconfigurationException(
-            "Trainer is already configured with a `BatchSizeFinder` callback. Please remove it if you"
-            " want to use tuner."
+            f"Trainer is already configured with a `{configured_callbacks[0]}` callback."
+            "Please remove it if you want to use the Tuner."
+        )
+    elif len(configured_callbacks) == 2:
+        raise MisconfigurationException(
+            "Trainer is already configured with `LearningRateFinder` and `BatchSizeFinder` callbacks."
+            " Please remove them if you want to use the Tuner."
         )

tests/tests_pytorch/tuner/test_lr_finder.py

@@ -435,10 +435,10 @@ def __init__(self):
 def test_if_lr_finder_callback_already_configured():
     """Test that an error is raised if `LearningRateFinder` is already configured inside `Tuner`"""
     cb = LearningRateFinder()
-    trainer = Trainer(auto_scale_batch_size=True, callbacks=cb)
+    trainer = Trainer(auto_lr_find=True, callbacks=cb)
     model = BoringModel()
 
-    with pytest.raises(MisconfigurationException, match="Trainer is already configured with a .* callback"):
+    with pytest.raises(MisconfigurationException, match="Trainer is already configured with a `LearningRateFinder`"):
         trainer.tune(model)
 
 

tests/tests_pytorch/tuner/test_scale_batch_size.py

@@ -393,7 +393,7 @@ def test_if_batch_size_finder_callback_already_configured():
     trainer = Trainer(auto_scale_batch_size=True, callbacks=cb)
     model = BoringModel()
 
-    with pytest.raises(MisconfigurationException, match="Trainer is already configured with a .* callback"):
+    with pytest.raises(MisconfigurationException, match="Trainer is already configured with a `BatchSizeFinder`"):
         trainer.tune(model)
 
 

tests/tests_pytorch/tuner/test_tuning.py

@@ -14,6 +14,7 @@
 import pytest
 
 from pytorch_lightning import Trainer
+from pytorch_lightning.callbacks import BatchSizeFinder, LearningRateFinder
 from pytorch_lightning.demos.boring_classes import BoringModel
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
 
@@ -25,3 +26,37 @@ def test_tuner_with_distributed_strategies():
 
     with pytest.raises(MisconfigurationException, match=r"not supported with `Trainer\(strategy='ddp'\)`"):
         trainer.tune(model)
+
+
+def test_tuner_with_already_configured_batch_size_finder():
+    """Test that an error is raised when tuner is already configured with BatchSizeFinder."""
+    trainer = Trainer(auto_scale_batch_size=True, callbacks=[BatchSizeFinder()])
+    model = BoringModel()
+
+    with pytest.raises(MisconfigurationException, match=r"Trainer is already configured with a `BatchSizeFinder`"):
+        trainer.tune(model)
+
+
+def test_tuner_with_already_configured_learning_rate_finder():
+    """Test that an error is raised when tuner is already configured with LearningRateFinder."""
+    trainer = trainer = Trainer(auto_lr_find=True, callbacks=[LearningRateFinder()])
+    model = BoringModel()
+
+    with pytest.raises(MisconfigurationException, match=r"Trainer is already configured with a `LearningRateFinder`"):
+        trainer.tune(model)
+
+
+def test_tuner_with_already_configured_learning_rate_finder_and_batch_size_finder():
+    """Test that an error is raised when tuner are already configured with LearningRateFinder and
+    BatchSizeFinder."""
+    trainer = trainer = Trainer(
+        auto_lr_find=True, auto_scale_batch_size=True, callbacks=[LearningRateFinder(), BatchSizeFinder()]
+    )
+    model = BoringModel()
+
+    with pytest.raises(
+        MisconfigurationException,
+        match=r"Trainer is already configured with `LearningRateFinder` and "
+        r"`BatchSizeFinder` callbacks. Please remove them if you want to use the Tuner.",
+    ):
+        trainer.tune(model)