Make Segmentation Tasks reproducible (#1094)

Co-authored-by: Ethan Harris <ethanwharris@gmail.com>

CHANGELOG.md

@@ -28,6 +28,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 - Fixed a bug where passing `predict_data_frame` to `ImageClassificationData.from_data_frame` raised an error ([#1088](https://github.com/PyTorchLightning/lightning-flash/pull/1088))
 
+- Fixed a bug where segmentation files / masks were loaded with an inconsistent ordering ([#1094](https://github.com/PyTorchLightning/lightning-flash/pull/1094))
+
 ### Removed
 
 ## [0.6.0] - 2021-13-12

flash/image/segmentation/input.py

@@ -124,6 +124,7 @@ def load_data(
     ) -> List[Dict[str, Any]]:
         self.load_labels_map(num_classes, labels_map)
         files = os.listdir(folder)
+        files.sort()
         if mask_folder is not None:
             mask_files = os.listdir(mask_folder)
 
@@ -137,6 +138,8 @@ def load_data(
 
             files = [os.path.join(folder, file) for file in all_files]
             mask_files = [os.path.join(mask_folder, file) for file in all_files]
+            files.sort()
+            mask_files.sort()
             return super().load_data(files, mask_files)
         return super().load_data(files)