implement --base-dir and --focus-tab to save_as_session

kitty/session.py

@@ -627,6 +627,16 @@ If specified, only save all windows (and their parent tabs/OS Windows) that matc
 search expression. See :ref:`search_syntax` for details on the search language. In particular if
 you want to only save windows that are present in the currently active session,
 use :code:`--match=session:.`.
+
+
+--base-dir
+When specified, relative session filenames will be saved to this directory instead of the current
+working directory. Absolute paths are not affected by this option.
+
+
+--focus-tab
+type=bool-set
+When enabled, add a focus_tab command to the saved session file to preserve the currently active tab.
 '''
 
 
@@ -634,6 +644,10 @@ def save_as_session_part2(boss: BossType, opts: SaveAsSessionOptions, path: str)
     if not path:
         return
     from .config import atomic_save
+    # Handle --base-dir option
+    if opts.base_dir and not os.path.isabs(path):
+        base_dir = os.path.abspath(os.path.expanduser(opts.base_dir))
+        path = os.path.join(base_dir, path)
     path = os.path.abspath(os.path.expanduser(path))
     session = '\n'.join(boss.serialize_state_as_session(path, opts))
     os.makedirs(os.path.dirname(path), exist_ok=True)

kitty/tabs.py

@@ -1317,7 +1317,10 @@ class TabManager:  # {{{
             hmap[at.id] = len(self.active_tab_history) + 1
         def skey(tab: Tab) -> int:
             return hmap.get(tab.id, -1)
-        for tab in sorted(self, key=skey):
+        active_tab_index = -1
+        for i, tab in enumerate(sorted(self, key=skey)):
+            if tab is self.active_tab:
+                active_tab_index = i
             ans.extend(tab.serialize_state_as_session(session_path, matched_windows, ser_opts))
         if ans:
             prefix = [] if is_first else ['', '', 'new_os_window']
@@ -1326,6 +1329,10 @@ class TabManager:  # {{{
             if self.wm_name and self.wm_name != appname:
                 prefix.append(f'os_window_name {self.wm_name}')
             ans = prefix + ans
+            # Add focus_tab command if --focus-tab option is enabled
+            if ser_opts.focus_tab and active_tab_index >= 0:
+                ans.append('')
+                ans.append(f'focus_tab {active_tab_index}')
         return ans
 
     @property