fixed a crash

screens/repo_view_screen.py

@@ -29,7 +29,7 @@ class RepoViewScreen(Screen):
             match file_name:
                 case "Makefile":
                     return "\ue673"
-                case "Dockerfile":
+                case "Dockerfile" | "Containerfile":
                     return "\ue7b0"
                 case "requirements.txt":
                     return "\ue73c"
@@ -38,7 +38,8 @@ class RepoViewScreen(Screen):
                 case "Cargo.lock" | "Cargo.toml":
                     return "\ue7a8"
             
-            extension = file_name[file_name.index(".")+1:]
+            if "." in file_name:
+                extension = file_name[file_name.find(".")+1:]
                 
                 match extension:
                     case 'c' | 'h':
@@ -87,9 +88,11 @@ class RepoViewScreen(Screen):
                         return "\ue634"
                     case "java":
                         return "\ue738"
-                case _:
+                    case _: # unrecognized file type
                         return "\uf15b"
-        else:
+            else: # has no dot in the name
+                return "\uf15b"
+        else: # is a folder
             return "\ue5ff"
     
     @work(thread=False, exclusive=True)