Refactor update_catalog_hashes to simplify single app handling and improve flow control

Author: stavros-k

catalog_reader/scripts/apps_hashes.py

@@ -45,21 +45,15 @@ def update_catalog_hashes(
         print('[\033[92mOK\x1B[0m]\tNo hashes found for library versions, skipping updating apps hashes')
         return
 
-    app_found = False
     is_single_app = train_name and app_name
     for train_dir in dev_directory.iterdir():
-        if is_single_app and app_found:
-            break
         if not train_dir.is_dir():
             continue
 
         if is_single_app and train_dir.name != train_name:
             continue
 
         for app_dir in train_dir.iterdir():
-            if is_single_app and app_found:
-                break
-
             if not app_dir.is_dir():
                 continue
 
@@ -108,9 +102,9 @@ def update_catalog_hashes(
             print(message)
 
             if is_single_app:
-                app_found = True
+                return
 
-    if is_single_app and not app_found:
+    if is_single_app:
         verrors.add('app', f'App {app_name!r} not found in train {train_name!r}')
         verrors.check()