mypy: Turn on return value checks

Its a shame GvR is married to "return None"
python/mypy#7511

Author: kovidgoyal

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 @@ def __enter__(self) -> '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 @@ def set_colors_to_current_theme(self) -> bool:
             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 @@ def active_file(self) -> Optional[File]:
             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 @@ def activate_next_ready_file(self) -> Optional[File]:
                 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 @@ def shortcut_action(self, key_event: KeyEventType) -> Optional[KeyActionType]:
         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 @@ def __call__(self, text: str, state: int) -> Optional[str]:
             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 @@ def __exit__(self, *a: Any) -> bool:
     def input(self) -> str:
         with self:
             return input(self.prompt)
+        return ''
 
 
 def develop() -> None:

kittens/unicode_input/main.py

@@ -157,6 +157,7 @@ def __init__(self, emoji_variation: str) -> None:
     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

kitty/boss.py

@@ -9,8 +9,8 @@
 from functools import partial
 from gettext import gettext as _
 from typing import (
-    Any, Callable, Dict, Generator, Iterable, List, Optional, Tuple, Union,
-    cast
+    Any, Callable, Dict, Iterable, Iterator, List, Optional, Tuple,
+    Union, cast
 )
 from weakref import WeakValueDictionary
 
@@ -27,16 +27,16 @@
 )
 from .fast_data_types import (
     CLOSE_BEING_CONFIRMED, GLFW_MOD_ALT, GLFW_MOD_CONTROL, GLFW_MOD_SHIFT,
-    GLFW_MOD_SUPER, IMPERATIVE_CLOSE_REQUESTED, NO_CLOSE_REQUESTED,
-    ChildMonitor, KeyEvent, add_timer, apply_options_update,
-    background_opacity_of, change_background_opacity, change_os_window_state,
-    cocoa_set_menubar_title, create_os_window, GLFW_PRESS, GLFW_MOUSE_BUTTON_LEFT,
-    current_application_quit_request, current_os_window, destroy_global_data,
-    focus_os_window, get_clipboard_string, get_options, get_os_window_size,
-    global_font_size, mark_os_window_for_close, os_window_font_size,
-    patch_global_colors, redirect_mouse_handling, ring_bell, safe_pipe,
-    set_application_quit_request, set_background_image, set_boss,
-    set_clipboard_string, set_in_sequence_mode, set_options,
+    GLFW_MOD_SUPER, GLFW_MOUSE_BUTTON_LEFT, GLFW_PRESS,
+    IMPERATIVE_CLOSE_REQUESTED, NO_CLOSE_REQUESTED, ChildMonitor, KeyEvent,
+    add_timer, apply_options_update, background_opacity_of,
+    change_background_opacity, change_os_window_state, cocoa_set_menubar_title,
+    create_os_window, current_application_quit_request, current_os_window,
+    destroy_global_data, focus_os_window, get_clipboard_string, get_options,
+    get_os_window_size, global_font_size, mark_os_window_for_close,
+    os_window_font_size, patch_global_colors, redirect_mouse_handling,
+    ring_bell, safe_pipe, set_application_quit_request, set_background_image,
+    set_boss, set_clipboard_string, set_in_sequence_mode, set_options,
     set_os_window_size, thread_write, toggle_fullscreen, toggle_maximized
 )
 from .key_encoding import get_name_to_functional_number_map
@@ -234,7 +234,7 @@ def add_os_window(
         self.os_window_map[os_window_id] = tm
         return os_window_id
 
-    def list_os_windows(self, self_window: Optional[Window] = None) -> Generator[OSWindowDict, None, None]:
+    def list_os_windows(self, self_window: Optional[Window] = None) -> Iterator[OSWindowDict]:
         with cached_process_data():
             active_tab, active_window = self.active_tab, self.active_window
             active_tab_manager = self.active_tab_manager
@@ -249,20 +249,20 @@ def list_os_windows(self, self_window: Optional[Window] = None) -> Generator[OSW
                 }
 
     @property
-    def all_tab_managers(self) -> Generator[TabManager, None, None]:
+    def all_tab_managers(self) -> Iterator[TabManager]:
         yield from self.os_window_map.values()
 
     @property
-    def all_tabs(self) -> Generator[Tab, None, None]:
+    def all_tabs(self) -> Iterator[Tab]:
         for tm in self.all_tab_managers:
             yield from tm
 
     @property
-    def all_windows(self) -> Generator[Window, None, None]:
+    def all_windows(self) -> Iterator[Window]:
         for tab in self.all_tabs:
             yield from tab
 
-    def match_windows(self, match: str) -> Generator[Window, None, None]:
+    def match_windows(self, match: str) -> Iterator[Window]:
         try:
             field, exp = match.split(':', 1)
         except ValueError:
@@ -305,8 +305,9 @@ def tab_for_window(self, window: Window) -> Optional[Tab]:
             for w in tab:
                 if w.id == window.id:
                     return tab
+        return None
 
-    def match_tabs(self, match: str) -> Generator[Tab, None, None]:
+    def match_tabs(self, match: str) -> Iterator[Tab]:
         try:
             field, exp = match.split(':', 1)
         except ValueError:
@@ -359,6 +360,7 @@ def set_active_window(self, window: Window, switch_os_window_if_needed: bool = F
                         if switch_os_window_if_needed and current_os_window() != os_window_id:
                             focus_os_window(os_window_id, True)
                         return os_window_id
+        return None
 
     def _new_os_window(self, args: Union[SpecialWindowInstance, Iterable[str]], cwd_from: Optional[int] = None) -> int:
         if isinstance(args, SpecialWindowInstance):
@@ -377,6 +379,7 @@ def active_window_for_cwd(self) -> Optional[Window]:
         t = self.active_tab
         if t is not None:
             return t.active_window_for_cwd
+        return None
 
     @ac('win', 'New OS Window with the same working directory as the currently active window')
     def new_os_window_with_cwd(self, *args: str) -> None:
@@ -595,7 +598,7 @@ def start(self, first_os_window_id: int) -> None:
             run_update_check(get_options().update_check_interval * 60 * 60)
             self.update_check_started = True
 
-    def handle_click_on_tab(self, os_window_id: int, x: int, button: int, modifiers: int, action: int) -> int:
+    def handle_click_on_tab(self, os_window_id: int, x: int, button: int, modifiers: int, action: int) -> None:
         tm = self.os_window_map.get(os_window_id)
         if tm is not None:
             tm.handle_click_on_tab(x, button, modifiers, action)
@@ -751,20 +754,17 @@ def set_background_opacity(self, opacity: str) -> None:
     @property
     def active_tab_manager(self) -> Optional[TabManager]:
         os_window_id = current_os_window()
-        if os_window_id is not None:
-            return self.os_window_map.get(os_window_id)
+        return None if os_window_id is None else self.os_window_map.get(os_window_id)
 
     @property
     def active_tab(self) -> Optional[Tab]:
         tm = self.active_tab_manager
-        if tm is not None:
-            return tm.active_tab
+        return None if tm is None else tm.active_tab
 
     @property
     def active_window(self) -> Optional[Window]:
         t = self.active_tab
-        if t is not None:
-            return t.active_window
+        return None if t is None else t.active_window
 
     def set_pending_sequences(self, sequences: SubSequenceMap, default_pending_action: Optional[KeyAction] = None) -> None:
         self.pending_sequences = sequences
@@ -783,6 +783,7 @@ def dispatch_possible_special_key(self, ev: KeyEvent) -> bool:
                 return True
         elif isinstance(key_action, KeyAction):
             return self.dispatch_action(key_action)
+        return False
 
     def clear_pending_sequences(self) -> None:
         self.pending_sequences = self.default_pending_action = None
@@ -1530,7 +1531,7 @@ def run_background_process(
         else:
             subprocess.Popen(cmd, env=env, cwd=cwd)
 
-    def pipe(self, source: str, dest: str, exe: str, *args: str) -> Window:
+    def pipe(self, source: str, dest: str, exe: str, *args: str) -> Optional[Window]:
         cmd = [exe] + list(args)
         window = self.active_window
         cwd_from = window.child.pid_for_cwd if window else None
@@ -1559,6 +1560,7 @@ def create_window() -> SpecialWindowInstance:
         else:
             env, stdin = self.process_stdin_source(stdin=source, window=window)
             self.run_background_process(cmd, cwd_from=cwd_from, stdin=stdin, env=env)
+        return None
 
     def args_to_special_window(self, args: Iterable[str], cwd_from: Optional[int] = None) -> SpecialWindowInstance:
         args = list(args)
@@ -1591,6 +1593,7 @@ def _new_tab(self, args: Union[SpecialWindowInstance, Iterable[str]], cwd_from:
         tm = self.active_tab_manager
         if tm is not None:
             return tm.new_tab(special_window=special_window, cwd_from=cwd_from, as_neighbor=as_neighbor)
+        return None
 
     def _create_tab(self, args: List[str], cwd_from: Optional[int] = None) -> None:
         as_neighbor = False
@@ -1615,21 +1618,22 @@ def new_tab_with_wd(self, wd: str) -> None:
 
     def _new_window(self, args: List[str], cwd_from: Optional[int] = None) -> Optional[Window]:
         tab = self.active_tab
-        if tab is not None:
-            allow_remote_control = False
-            location = None
-            if args and args[0].startswith('!'):
-                location = args[0][1:].lower()
-                args = args[1:]
-            if args and args[0] == '@':
-                args = args[1:]
-                allow_remote_control = True
-            if args:
-                return tab.new_special_window(
-                    self.args_to_special_window(args, cwd_from=cwd_from),
-                    location=location, allow_remote_control=allow_remote_control)
-            else:
-                return tab.new_window(cwd_from=cwd_from, location=location, allow_remote_control=allow_remote_control)
+        if tab is None:
+            return None
+        allow_remote_control = False
+        location = None
+        if args and args[0].startswith('!'):
+            location = args[0][1:].lower()
+            args = args[1:]
+        if args and args[0] == '@':
+            args = args[1:]
+            allow_remote_control = True
+        if args:
+            return tab.new_special_window(
+                self.args_to_special_window(args, cwd_from=cwd_from),
+                location=location, allow_remote_control=allow_remote_control)
+        else:
+            return tab.new_window(cwd_from=cwd_from, location=location, allow_remote_control=allow_remote_control)
 
     @ac('win', 'Create a new window')
     def new_window(self, *args: str) -> None:

kitty/child.py

@@ -333,6 +333,7 @@ def current_cwd(self) -> Optional[str]:
         with suppress(Exception):
             assert self.pid is not None
             return cwd_of_process(self.pid)
+        return None
 
     @property
     def pid_for_cwd(self) -> Optional[int]:
@@ -349,6 +350,7 @@ def foreground_cwd(self) -> Optional[str]:
         with suppress(Exception):
             assert self.pid_for_cwd is not None
             return cwd_of_process(self.pid_for_cwd) or None
+        return None
 
     @property
     def foreground_environ(self) -> Dict[str, str]:

kitty/file_transmission.py

@@ -951,3 +951,4 @@ def start_send(self, aid: str) -> None:
 
     def callback_after(self, callback: Callable[[Optional[int]], None], timeout: float = 0) -> Optional[int]:
         callback(None)
+        return None

kitty/fonts/box_drawing.py

@@ -10,7 +10,7 @@
 from functools import partial as p, wraps
 from itertools import repeat
 from typing import (
-    Any, Callable, Dict, Generator, Iterable, List, MutableSequence, Optional,
+    Any, Callable, Dict, Iterable, Iterator, List, MutableSequence, Optional,
     Sequence, Tuple, cast
 )
 
@@ -314,6 +314,7 @@ def pt_to_coords(p: str) -> Tuple[int, int]:
             return width - 1, mid_y
         if p == 'b':
             return mid_x, height - 1
+        raise KeyError(f'Unknown p: {p}')
 
     for x in pts:
         p1, p2 = map(pt_to_coords, x)
@@ -353,7 +354,7 @@ def find_bezier_for_D(width: int, height: int) -> int:
         cx += 1
 
 
-def get_bezier_limits(bezier_x: ParameterizedFunc, bezier_y: ParameterizedFunc) -> Generator[Tuple[float, float], None, int]:
+def get_bezier_limits(bezier_x: ParameterizedFunc, bezier_y: ParameterizedFunc) -> Iterator[Tuple[float, float]]:
     start_x = int(bezier_x(0))
     max_x = int(bezier_x(0.5))
     last_t, t_limit = 0., 0.5
@@ -1043,8 +1044,9 @@ def render_missing_glyph(buf: BufType, width: int, height: int) -> None:
 
 def test_char(ch: str, sz: int = 48) -> None:
     # kitty +runpy "from kitty.fonts.box_drawing import test_char; test_char('XXX')"
-    from .render import display_bitmap, setup_for_testing
     from kitty.fast_data_types import concat_cells, set_send_sprite_to_gpu
+
+    from .render import display_bitmap, setup_for_testing
     with setup_for_testing('monospace', sz) as (_, width, height):
         buf = bytearray(width * height)
         try:
@@ -1062,9 +1064,10 @@ def join_cells(*cells: bytes) -> bytes:
 
 
 def test_drawing(sz: int = 48, family: str = 'monospace', start: int = 0x2500, num_rows: int = 10, num_cols: int = 16) -> None:
-    from .render import display_bitmap, setup_for_testing
     from kitty.fast_data_types import concat_cells, set_send_sprite_to_gpu
 
+    from .render import display_bitmap, setup_for_testing
+
     with setup_for_testing(family, sz) as (_, width, height):
         space = bytearray(width * height)
 

kitty/layout/base.py

@@ -69,6 +69,7 @@ def idx_for_id(win_id: int, windows: Iterable[WindowType]) -> Optional[int]:
     for i, w in enumerate(windows):
         if w.id == win_id:
             return i
+    return None
 
 
 def set_layout_options(opts: Options) -> None:

kitty/layout/grid.py

@@ -81,6 +81,7 @@ def on_col_done(col_windows: List[int]) -> None:
                 if idx == window_idx:
                     return row_num, col_num
                 row_num += 1
+            return 0, 0
 
         row_num, col_num = position_for_window_idx(idx)