Allow showing the currently active session name in the tab bar

docs/sessions.rst

@@ -60,6 +60,21 @@ In this manner you can define as many projects/sessions as you like and easily
 switch between them with a keypress.
 
 
+Displaying the currently active session name
+----------------------------------------------
+
+You can display the name of the currently active session file in the kitty tab
+bar using :opt:`tab_title_template`. For example, using the value::
+
+    {session_name} {title}
+
+will show you the name of the session file the current tab was loaded from, as
+well as the normal tab title. Or alternatively, you can set the tab title
+directly to a project name in the session file itself when creating the tab,
+like this::
+
+    new_tab My Project Name
+
 .. _complex_sessions:
 
 More complex sessions

kitty/options/definition.py

@@ -1471,6 +1471,8 @@ use :code:`{sup.index}`. All data available is:
     The tab index usable with :ac:`goto_tab N <goto_tab>` shortcuts.
 :code:`layout_name`
     The current layout name.
+:code:`session_name`
+    The name of the kitty session file from which this tab was created, if any.
 :code:`num_windows`
     The number of windows in the tab.
 :code:`num_window_groups`

kitty/tab_bar.py

@@ -51,6 +51,7 @@ class TabBarData(NamedTuple):
     num_of_windows_with_progress: int
     total_progress: int
     last_focused_window_with_progress_id: int
+    session_name: str
 
 
 class DrawData(NamedTuple):

kitty/tabs.py

@@ -1374,6 +1374,7 @@ class TabManager:  # {{{
                 has_activity_since_last_focus, t.active_fg, t.active_bg,
                 t.inactive_fg, t.inactive_bg, t.num_of_windows_with_progress,
                 t.total_progress, t.last_focused_window_with_progress_id,
+                t.created_in_session_name,
             ))
         return ans