fix: move ProgressBar and ModelCheckpoint callbacks to the end in reorder_callbacks

src/lightning/pytorch/trainer/connectors/callback_connector.py

@@ -212,31 +212,35 @@ def _attach_model_callbacks(self) -> None:
 
     @staticmethod
     def _reorder_callbacks(callbacks: list[Callback]) -> list[Callback]:
-        """Moves all the tuner specific callbacks at the beginning of the list and all the `ModelCheckpoint` callbacks
-        to the end of the list. The sequential order within the group of checkpoint callbacks is preserved, as well as
-        the order of all other callbacks.
+        """Reorders a list of callbacks such that:
+
+            1. All `tuner-specific` callbacks appear at the beginning.
+            2. `ProgressBar` followed by `ModelCheckpoint` callbacks appear at the end.
+            3. All other callbacks maintain their relative order.
 
         Args:
-            callbacks: A list of callbacks.
+            callbacks (list[Callback]): The list of callbacks to reorder.
 
         Return:
-            A new list in which the first elements are tuner specific callbacks and last elements are ModelCheckpoints
-            if there were any present in the input.
+            list[Callback]: A new list with callbacks reordered as described above.
 
         """
         tuner_callbacks: list[Callback] = []
         other_callbacks: list[Callback] = []
+        progress_bar_callbacks: list[Callback] = []
         checkpoint_callbacks: list[Callback] = []
 
         for cb in callbacks:
             if isinstance(cb, (BatchSizeFinder, LearningRateFinder)):
                 tuner_callbacks.append(cb)
             elif isinstance(cb, Checkpoint):
                 checkpoint_callbacks.append(cb)
+            elif isinstance(cb, ProgressBar):
+                progress_bar_callbacks.append(cb)
             else:
                 other_callbacks.append(cb)
 
-        return tuner_callbacks + other_callbacks + checkpoint_callbacks
+        return tuner_callbacks + other_callbacks + progress_bar_callbacks + checkpoint_callbacks
 
 
 def _validate_callbacks_list(callbacks: list[Callback]) -> None:

tests/tests_pytorch/callbacks/test_callbacks.py

@@ -83,7 +83,9 @@ def configure_callbacks(self):
             return model_callback_mock
 
     model = TestModel()
-    trainer = Trainer(default_root_dir=tmp_path, fast_dev_run=True, enable_checkpointing=False)
+    trainer = Trainer(
+        default_root_dir=tmp_path, fast_dev_run=True, enable_checkpointing=False, enable_progress_bar=False
+    )
 
     callbacks_before_fit = trainer.callbacks.copy()
     assert callbacks_before_fit

tests/tests_pytorch/trainer/connectors/test_callback_connector.py

@@ -36,8 +36,8 @@
 
 
 @patch("lightning.pytorch.trainer.connectors.callback_connector._RICH_AVAILABLE", False)
-def test_checkpoint_callbacks_are_last(tmp_path):
-    """Test that checkpoint callbacks always come last."""
+def test_progressbar_and_checkpoint_callbacks_are_last(tmp_path):
+    """Test that progress bar and checkpoint callbacks always come last."""
     checkpoint1 = ModelCheckpoint(tmp_path / "path1", filename="ckpt1", monitor="val_loss_c1")
     checkpoint2 = ModelCheckpoint(tmp_path / "path2", filename="ckpt2", monitor="val_loss_c2")
     early_stopping = EarlyStopping(monitor="foo")
@@ -48,9 +48,9 @@ def test_checkpoint_callbacks_are_last(tmp_path):
     # no model reference
     trainer = Trainer(callbacks=[checkpoint1, progress_bar, lr_monitor, model_summary, checkpoint2])
     assert trainer.callbacks == [
-        progress_bar,
         lr_monitor,
         model_summary,
+        progress_bar,
         checkpoint1,
         checkpoint2,
     ]
@@ -62,9 +62,9 @@ def test_checkpoint_callbacks_are_last(tmp_path):
     cb_connector = _CallbackConnector(trainer)
     cb_connector._attach_model_callbacks()
     assert trainer.callbacks == [
-        progress_bar,
         lr_monitor,
         model_summary,
+        progress_bar,
         checkpoint1,
         checkpoint2,
     ]
@@ -77,10 +77,10 @@ def test_checkpoint_callbacks_are_last(tmp_path):
     cb_connector = _CallbackConnector(trainer)
     cb_connector._attach_model_callbacks()
     assert trainer.callbacks == [
-        progress_bar,
         lr_monitor,
         early_stopping,
         model_summary,
+        progress_bar,
         checkpoint1,
         checkpoint2,
     ]
@@ -95,10 +95,10 @@ def test_checkpoint_callbacks_are_last(tmp_path):
     cb_connector._attach_model_callbacks()
     assert trainer.callbacks == [
         batch_size_finder,
-        progress_bar,
         lr_monitor,
         early_stopping,
         model_summary,
+        progress_bar,
         checkpoint2,
         checkpoint1,
     ]
@@ -200,7 +200,7 @@ def _attach_callbacks(trainer_callbacks, model_callbacks):
         trainer_callbacks=[progress_bar, EarlyStopping(monitor="red")],
         model_callbacks=[early_stopping1],
     )
-    assert trainer.callbacks == [progress_bar, early_stopping1]
+    assert trainer.callbacks == [early_stopping1, progress_bar]  # progress_bar should be last
 
     # multiple callbacks of the same type in trainer
     trainer = _attach_callbacks(
@@ -225,7 +225,7 @@ def _attach_callbacks(trainer_callbacks, model_callbacks):
         ],
         model_callbacks=[early_stopping1, lr_monitor, grad_accumulation, early_stopping2],
     )
-    assert trainer.callbacks == [progress_bar, early_stopping1, lr_monitor, grad_accumulation, early_stopping2]
+    assert trainer.callbacks == [early_stopping1, lr_monitor, grad_accumulation, early_stopping2, progress_bar]
 
     class CustomProgressBar(TQDMProgressBar): ...