Close validation progress bar before updating training bar (#18503)

(cherry picked from commit a3f6e98)

Author: awaelchli

src/lightning/pytorch/CHANGELOG.md

@@ -36,6 +36,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 
 
+- Fixed visual glitch with the TQDM progress bar leaving the validation bar incomplete before switching back to the training display ([#18503](https://github.com/Lightning-AI/lightning/pull/18503))
+
+
 ## [2.0.7] - 2023-08-14
 
 ### Added

src/lightning/pytorch/callbacks/progress/tqdm_progress.py

@@ -240,8 +240,8 @@ def on_sanity_check_start(self, *_: Any) -> None:
         self.train_progress_bar = Tqdm(disable=True)  # dummy progress bar
 
     def on_sanity_check_end(self, *_: Any) -> None:
-        self.train_progress_bar.close()
         self.val_progress_bar.close()
+        self.train_progress_bar.close()
 
     def on_train_start(self, *_: Any) -> None:
         self.train_progress_bar = self.init_train_tqdm()
@@ -300,10 +300,10 @@ def on_validation_batch_end(
             _update_n(self.val_progress_bar, n)
 
     def on_validation_end(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule") -> None:
-        if self._train_progress_bar is not None and trainer.state.fn == "fit":
-            self.train_progress_bar.set_postfix(self.get_metrics(trainer, pl_module))
         self.val_progress_bar.close()
         self.reset_dataloader_idx_tracker()
+        if self._train_progress_bar is not None and trainer.state.fn == "fit":
+            self.train_progress_bar.set_postfix(self.get_metrics(trainer, pl_module))
 
     def on_test_start(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule") -> None:
         self.test_progress_bar = self.init_test_tqdm()