mypy: Turn on return value checks

Its a shame GvR is married to "return None"
https://github.com/python/mypy/issues/7511

kittens/broadcast/main.py

@@ -106,6 +106,7 @@ def main(args: List[str]) -> Optional[Dict[str, Any]]:
     loop = Loop()
     handler = Broadcast(opts, items)
     loop.loop(handler)
+    return None
 
 
 if __name__ == '__main__':

kittens/diff/patch.py

@@ -24,6 +24,7 @@ def find_differ() -> Optional[str]:
         return GIT_DIFF
     if shutil.which('diff'):
         return DIFF_DIFF
+    return None
 
 
 def set_diff_command(opt: str) -> None:

kittens/hints/main.py

@@ -688,6 +688,7 @@ def main(args: List[str]) -> Optional[Dict[str, Any]]:
         import traceback
         traceback.print_exc()
         input(_('Press Enter to quit'))
+    return None
 
 
 def linenum_handle_result(args: List[str], data: Dict[str, Any], target_window_id: int, boss: BossType, extra_cli_args: Sequence[str], *a: Any) -> None:

kittens/remote_file/main.py

@@ -132,7 +132,7 @@ class ControlMaster:
             self.dest = os.path.join(self.tdir, os.path.basename(self.remote_path))
         return self
 
-    def __exit__(self, *a: Any) -> bool:
+    def __exit__(self, *a: Any) -> None:
         subprocess.Popen(
             self.batch_cmd_prefix + ['-O', 'exit', self.conn_data.hostname],
             stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, stdin=subprocess.DEVNULL
@@ -215,6 +215,7 @@ def main(args: List[str]) -> Result:
         import traceback
         traceback.print_exc()
         show_error('Failed with unhandled exception')
+    return None
 
 
 def save_as(conn_data: SSHConnectionData, remote_path: str, cli_opts: RemoteFileCLIOptions) -> None:
@@ -312,6 +313,7 @@ def handle_action(action: str, cli_opts: RemoteFileCLIOptions) -> Result:
     elif action == 'save':
         print('Saving', cli_opts.path, 'from', cli_opts.hostname)
         save_as(conn_data, remote_path, cli_opts)
+    return None
 
 
 @result_handler()

kittens/themes/main.py

@@ -203,6 +203,7 @@ class ThemesHandler(Handler):
             col = color_as_sharp(color_from_int(o.color_table[i]))
             cmds.append(f'{i};{col}')
         self.print(end='\033]4;' + ';'.join(cmds) + '\033\\')
+        return True
 
     def redraw_after_category_change(self) -> None:
         self.themes_list.update_themes(self.all_themes.filtered(self.filter_map[self.current_category]))

kittens/transfer/send.py

@@ -312,6 +312,7 @@ class SendManager:
             ans = self.files[self.active_idx]
             if ans.state is FileState.transmitting:
                 return ans
+        return None
 
     def activate_next_ready_file(self) -> Optional[File]:
         if self.active_idx is not None:
@@ -325,6 +326,7 @@ class SendManager:
                 return f
         self.active_idx = None
         self.update_collective_statuses()
+        return None
 
     def update_collective_statuses(self) -> None:
         found_not_started = found_not_done = False

kittens/tui/handler.py

@@ -83,6 +83,7 @@ class Handler:
         for sc, action in self._key_shortcuts.items():
             if key_event.matches(sc):
                 return action
+        return None
 
     def __enter__(self) -> None:
         if self._image_manager is not None:

kittens/tui/path_completer.py

@@ -132,6 +132,7 @@ class PathCompleter:
             options = self.cache[text] = tuple(find_completions(text))
         if options and state < len(options):
             return options[state]
+        return None
 
     def __exit__(self, *a: Any) -> bool:
         import readline
@@ -143,6 +144,7 @@ class PathCompleter:
     def input(self) -> str:
         with self:
             return input(self.prompt)
+        return ''
 
 
 def develop() -> None:

kittens/unicode_input/main.py

@@ -157,6 +157,7 @@ class Table:
     def current_codepoint(self) -> Optional[int]:
         if self.codepoints:
             return self.codepoints[self.current_idx]
+        return None
 
     def set_codepoints(self, codepoints: List[int], mode: str = HEX, current_idx: int = 0) -> None:
         self.codepoints = codepoints