Fix to avoid val progress bar disappear after validate

CHANGELOG.md

@@ -503,6 +503,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Disbled sampler replacement when using `IterableDataset` ([#11507](https://github.com/PyTorchLightning/pytorch-lightning/pull/11507))
 
 
+- Fixed an issue to avoid val bar disappear after `trainer.validate()` ([#11700](https://github.com/PyTorchLightning/pytorch-lightning/pull/11700))
+
+
 - Fixed the mid-epoch warning call while resuming training ([#11556](https://github.com/PyTorchLightning/pytorch-lightning/pull/11556))
 
 

pytorch_lightning/callbacks/progress/tqdm_progress.py

@@ -227,12 +227,12 @@ def init_predict_tqdm(self) -> Tqdm:
     def init_validation_tqdm(self) -> Tqdm:
         """Override this to customize the tqdm bar for validation."""
         # The main progress bar doesn't exist in `trainer.validate()`
-        has_main_bar = self._main_progress_bar is not None
+        has_main_bar = self.trainer.state.fn != "validate"
         bar = Tqdm(
             desc="Validating",
             position=(2 * self.process_position + has_main_bar),
             disable=self.is_disabled,
-            leave=False,
+            leave=not has_main_bar,
             dynamic_ncols=True,
             file=sys.stdout,
         )

tests/callbacks/test_tqdm_progress_bar.py

@@ -90,10 +90,12 @@ def test_tqdm_progress_bar_totals(tmpdir):
     m = bar.total_val_batches
     assert len(trainer.train_dataloader) == n
     assert bar.main_progress_bar.total == n + m
+    assert bar.main_progress_bar.leave
 
     # check val progress bar total
     assert sum(len(loader) for loader in trainer.val_dataloaders) == m
     assert bar.val_progress_bar.total == m
+    assert not bar.val_progress_bar.leave
 
     # main progress bar should have reached the end (train batches + val batches)
     assert bar.main_progress_bar.n == n + m
@@ -113,13 +115,15 @@ def test_tqdm_progress_bar_totals(tmpdir):
     assert bar.val_progress_bar.total == m
     assert bar.val_progress_bar.n == m
     assert bar.val_batch_idx == m
+    assert bar.val_progress_bar.leave
 
     trainer.test(model)
 
     # check test progress bar total
     k = bar.total_test_batches
     assert sum(len(loader) for loader in trainer.test_dataloaders) == k
     assert bar.test_progress_bar.total == k
+    assert bar.test_progress_bar.leave
 
     # test progress bar should have reached the end
     assert bar.test_progress_bar.n == k