Allow using the full launch command in session files

Note this is slightly backward incompatible.

docs/changelog.rst

@@ -11,6 +11,11 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
   used by full screen terminal programs and even games, see
   :doc:`keyboard-protocol` (:iss:`3248`)
 
+- **Backward incompatibility**: Session files now use the full :doc:`launch <launch>`
+  command with all its capabilities. However, the syntax of the command is
+  slightly different from before. In particular watchers are now specified
+  directly on launch and env vars are set using ``--env``.
+
 - diff kitten: Implement recursive diff over SSH (:iss:`3268`)
 
 - ssh kitten: Allow using python instead of the shell on the server, useful if

docs/index.rst

@@ -340,7 +340,7 @@ For example:
     launch zsh
     # Create a window with some environment variables set and run
     # vim in it
-    launch env FOO=BAR vim
+    launch --env FOO=BAR vim
     # Set the title for the next window
     title Chat with x
     launch irssi --profile x
@@ -367,14 +367,9 @@ For example:
     focus
     launch emacs
 
-    # Add a watcher that will be called with various events that occur
+.. note::
-    # on all subsequent windows. See the documentation of the launch command
+    The :doc:`launch <launch>` command when used in a session file
-    # for details on watchers.
+    cannot create new OS windows, or tabs.
-    watcher /some/python/file.py
-    launch mpd
-    launch irssi
-    # Remove the watcher for further windows
-    watcher clear
 
 
 Mouse features

kitty/boss.py

@@ -177,12 +177,8 @@ class Boss:
             cocoa_set_notification_activated_callback(notification_activated)
 
     def startup_first_child(self, os_window_id: Optional[int]) -> None:
-        from kitty.launch import load_watch_modules
         startup_sessions = create_sessions(self.opts, self.args, default_session=self.opts.startup_session)
-        watchers = load_watch_modules(self.args.watcher)
         for startup_session in startup_sessions:
-            if watchers is not None and watchers.has_watchers:
-                startup_session.add_watchers_to_all_windows(watchers)
             self.add_os_window(startup_session, os_window_id=os_window_id)
             os_window_id = None
             if self.args.start_as != 'normal':

kitty/launch.py

@@ -4,7 +4,7 @@
 
 
 from functools import lru_cache
-from typing import Any, Dict, List, Optional, Sequence, Tuple
+from typing import Any, Dict, List, NamedTuple, Optional, Sequence
 
 from .boss import Boss
 from .child import Child
@@ -13,7 +13,7 @@ from .cli_stub import LaunchCLIOptions
 from .constants import resolve_custom_file
 from .fast_data_types import set_clipboard_string
 from .tabs import Tab
-from .utils import find_exe, set_primary_selection, read_shell_environment
+from .utils import find_exe, read_shell_environment, set_primary_selection
 from .window import Watchers, Window
 
 try:
@@ -22,6 +22,11 @@ except ImportError:
     TypedDict = Dict[str, Any]
 
 
+class LaunchSpec(NamedTuple):
+    opts: LaunchCLIOptions
+    args: List[str]
+
+
 @lru_cache(maxsize=2)
 def options_spec() -> str:
     return '''
@@ -159,13 +164,13 @@ Set the WM_NAME property on X11 for the newly created OS Window when using
 ''' + WATCHER_DEFINITION
 
 
-def parse_launch_args(args: Optional[Sequence[str]] = None) -> Tuple[LaunchCLIOptions, List[str]]:
+def parse_launch_args(args: Optional[Sequence[str]] = None) -> LaunchSpec:
     args = list(args or ())
     try:
         opts, args = parse_args(result_class=LaunchCLIOptions, args=args, ospec=options_spec)
     except SystemExit as e:
         raise ValueError from e
-    return opts, args
+    return LaunchSpec(opts, args)
 
 
 def get_env(opts: LaunchCLIOptions, active_child: Child) -> Dict[str, str]:
@@ -234,7 +239,13 @@ class LaunchKwds(TypedDict):
     stdin: Optional[bytes]
 
 
-def launch(boss: Boss, opts: LaunchCLIOptions, args: List[str], target_tab: Optional[Tab] = None) -> Optional[Window]:
+def launch(
+    boss: Boss,
+    opts: LaunchCLIOptions,
+    args: List[str],
+    target_tab: Optional[Tab] = None,
+    force_target_tab: bool = False
+) -> Optional[Window]:
     active = boss.active_window_for_cwd
     active_child = getattr(active, 'child', None)
     env = get_env(opts, active_child)
@@ -310,6 +321,9 @@ def launch(boss: Boss, opts: LaunchCLIOptions, args: List[str], target_tab: Opti
                 set_clipboard_string(stdin)
             else:
                 set_primary_selection(stdin)
+    else:
+        if force_target_tab:
+            tab = target_tab
         else:
             tab = tab_for_window(boss, opts, target_tab)
         if tab is not None:

kitty/session.py

@@ -4,7 +4,7 @@
 
 import shlex
 import sys
-from typing import Generator, List, Optional, Union
+from typing import Generator, List, Optional, Sequence, Union
 
 from .cli_stub import CLIOptions
 from .config_data import to_layout_names
@@ -14,7 +14,6 @@ from .options_stub import Options
 from .os_window_size import WindowSize, WindowSizeData, WindowSizes
 from .typing import SpecialWindowInstance
 from .utils import log_error, resolved_shell
-from .window import Watchers
 
 
 def get_os_window_sizing_data(opts: Options, session: Optional['Session'] = None) -> WindowSizeData:
@@ -27,44 +26,31 @@ def get_os_window_sizing_data(opts: Options, session: Optional['Session'] = None
 
 class Tab:
 
-    def __init__(self, opts: Options, name: str, watchers: Watchers):
+    def __init__(self, opts: Options, name: str):
-        self.windows: List['SpecialWindowInstance'] = []
+        from .launch import LaunchSpec
+        self.windows: List[Union[LaunchSpec, 'SpecialWindowInstance']] = []
         self.name = name.strip()
         self.active_window_idx = 0
         self.enabled_layouts = opts.enabled_layouts
         self.layout = (self.enabled_layouts or ['tall'])[0]
         self.cwd: Optional[str] = None
         self.next_title: Optional[str] = None
-        self.watchers: Watchers = watchers.copy()
 
 
 class Session:
 
-    def __init__(self, default_title: Optional[str] = None):
+    def __init__(self, default_title: Optional[str] = None, default_watchers: Sequence[str] = ()):
         self.tabs: List[Tab] = []
+        self.default_watchers = list(default_watchers)
         self.active_tab_idx = 0
         self.default_title = default_title
         self.os_window_size: Optional[WindowSizes] = None
         self.os_window_class: Optional[str] = None
-        self.watchers = Watchers()
-
-    def add_watchers_to_all_windows(self, watchers: Watchers) -> None:
-        def add(w: 'SpecialWindowInstance') -> 'SpecialWindowInstance':
-            if w.watchers is None:
-                return w._replace(watchers=watchers)
-            wt = w.watchers.copy()
-            wt.add(watchers)
-            return w._replace(watchers=wt)
-
-        for tab in self.tabs:
-            tab.windows = [add(w) for w in tab.windows]
 
     def add_tab(self, opts: Options, name: str = '') -> None:
         if self.tabs and not self.tabs[-1].windows:
             del self.tabs[-1]
-        if self.tabs:
+        self.tabs.append(Tab(opts, name))
-            self.tabs[-1].watchers = self.watchers.copy()
-        self.tabs.append(Tab(opts, name, self.watchers))
 
     def set_next_title(self, title: str) -> None:
         self.tabs[-1].next_title = title.strip()
@@ -75,22 +61,18 @@ class Session:
         self.tabs[-1].layout = val
 
     def add_window(self, cmd: Union[None, str, List[str]]) -> None:
-        if cmd:
+        from .launch import parse_launch_args
-            cmd = shlex.split(cmd) if isinstance(cmd, str) else cmd
+        if isinstance(cmd, str):
-        else:
+            cmd = shlex.split(cmd)
-            cmd = None
+        spec = parse_launch_args(cmd)
-        from .tabs import SpecialWindow
+        if self.default_watchers:
+            spec.opts.watcher = list(spec.opts.watcher) + self.default_watchers
         t = self.tabs[-1]
-        watchers: Optional[Watchers] = None
+        spec.opts.cwd = spec.opts.cwd or t.cwd
-        if self.watchers.has_watchers:
+        t.windows.append(spec)
-            watchers = self.watchers.copy()
-        sw = SpecialWindow(cmd, cwd=t.cwd, override_title=t.next_title or self.default_title, watchers=watchers)
-        t.windows.append(sw)
         t.next_title = None
 
     def add_special_window(self, sw: 'SpecialWindowInstance') -> None:
-        if self.watchers.has_watchers:
-            sw = sw._replace(watchers=self.watchers.copy())
         self.tabs[-1].windows.append(sw)
 
     def focus(self) -> None:
@@ -112,10 +94,7 @@ def parse_session(raw: str, opts: Options, default_title: Optional[str] = None)
         from .tabs import SpecialWindow
         for t in ans.tabs:
             if not t.windows:
-                w: Optional[Watchers] = None
+                t.windows.append(SpecialWindow(cmd=resolved_shell(opts), override_title=default_title))
-                if t.watchers.has_watchers:
-                    w = t.watchers.copy()
-                t.windows.append(SpecialWindow(cmd=resolved_shell(opts), watchers=w, override_title=default_title))
         return ans
 
     ans = Session(default_title)
@@ -133,9 +112,7 @@ def parse_session(raw: str, opts: Options, default_title: Optional[str] = None)
                 ans.add_tab(opts, rest)
             elif cmd == 'new_os_window':
                 yield finalize_session(ans)
-                wt = ans.watchers
                 ans = Session(default_title)
-                ans.watchers = wt.copy()
                 ans.add_tab(opts, rest)
             elif cmd == 'layout':
                 ans.set_layout(rest)
@@ -155,14 +132,6 @@ def parse_session(raw: str, opts: Options, default_title: Optional[str] = None)
                 ans.os_window_size = WindowSizes(WindowSize(*w), WindowSize(*h))
             elif cmd == 'os_window_class':
                 ans.os_window_class = rest
-            elif cmd == 'watcher':
-                from .launch import load_watch_modules
-                if rest == 'clear':
-                    ans.watchers = Watchers()
-                else:
-                    watchers = load_watch_modules((rest,))
-                    if watchers is not None:
-                        ans.watchers.add(watchers)
             else:
                 raise ValueError('Unknown command in session file: {}'.format(cmd))
     yield finalize_session(ans)
@@ -194,7 +163,8 @@ def create_sessions(
         else:
             yield from parse_session(session_data, opts, getattr(args, 'title', None))
             return
-    ans = Session()
+    default_watchers = args.watcher if args else ()
+    ans = Session(default_watchers=default_watchers)
     current_layout = opts.enabled_layouts[0] if opts.enabled_layouts else 'tall'
     ans.add_tab(opts)
     ans.tabs[-1].layout = current_layout

kitty/tabs.py

@@ -137,7 +137,11 @@ class Tab:  # {{{
 
     def startup(self, session_tab: 'SessionTab') -> None:
         for cmd in session_tab.windows:
+            if isinstance(cmd, SpecialWindowInstance):
                 self.new_special_window(cmd)
+            else:
+                from .launch import launch
+                launch(get_boss(), cmd.opts, cmd.args, target_tab=self, force_target_tab=True)
         self.windows.set_active_window_group_for(self.windows.all_windows[session_tab.active_window_idx])
 
     def serialize_state(self) -> Dict[str, Any]: