[verified] fix(session): start nested AT-SPI registry

session/frametop-session.sh

@@ -29,7 +29,7 @@ for var in $(compgen -e); do
   case $var in
     LD_LIBRARY_PATH | LD_PRELOAD | STEAM_* | Steam* | SRT_* | PRESSURE_VESSEL_* | MANGOHUD_* | \
       ENABLE_VK_LAYER_VALVE_steam_overlay_* | STEAMVIDEOTOKEN | QT_IM_MODULE | GTK_IM_MODULE | \
-      XMODIFIERS) unset "$var" ;;
+      XMODIFIERS | AT_SPI_BUS_ADDRESS) unset "$var" ;;
   esac
 done
 
@@ -190,6 +190,21 @@ if [ "$remote" = 1 ]; then
   "$here/remote-ctl.sh" start
 fi
 
+# AT-SPI: start the registry inside Plasma's autostart, after KWin has published the
+# nested displays. Starting it before startplasma could bind to the host's X display.
+# This config belongs only to Frametop; the host desktop's autostart is unchanged.
+autostart=$XDG_CONFIG_HOME/autostart/frametop-atspi.desktop
+mkdir -p "$(dirname "$autostart")"
+cat > "$autostart" <<EOF
+[Desktop Entry]
+Type=Application
+Name=Frametop accessibility
+Exec="$here/ft-atspi"
+X-KDE-autostart-phase=2
+OnlyShowIn=KDE;
+NoDisplay=true
+EOF
+
 # ft-floatd (floating windows) runs inside the Plasma session, on its D-Bus: started from
 # the session's autostart, which only this desktop reads (XDG_CONFIG_HOME above).
 autostart=$XDG_CONFIG_HOME/autostart/frametop-floatd.desktop

session/ft-atspi

@@ -0,0 +1,86 @@
+#!/usr/bin/python3
+"""Start AT-SPI on this nested desktop's live bus, after KWin has set its displays."""
+import ast
+import os
+import signal
+import subprocess
+import sys
+import time
+
+DBUS = "org.freedesktop.DBus"
+DBUS_PATH = "/org/freedesktop/DBus"
+REGISTRY = "org.a11y.atspi.Registry"
+
+
+def call(address, destination, path, method, *args):
+    return subprocess.run(
+        ["gdbus", "call", "--address", address, "--dest", destination,
+         "--object-path", path, "--method", method, "--timeout", "5", *args],
+        check=True, capture_output=True, text=True, timeout=6).stdout.strip()
+
+
+def stop(child):
+    if child.poll() is None:
+        child.terminate()
+    try:
+        child.wait(timeout=3)
+    except subprocess.TimeoutExpired:
+        child.kill()
+        child.wait()
+
+
+def run_registry(address, session):
+    # SteamOS's registryd stays alive after a bus disconnect. Keep only our own
+    # child tied to both private buses; no host PID lookup or broad process kill.
+    registry = subprocess.Popen(["/usr/lib/at-spi2-registryd"])
+    try:
+        while registry.poll() is None:
+            try:
+                call(session, DBUS, DBUS_PATH, DBUS + ".GetId")
+                call(address, DBUS, DBUS_PATH, DBUS + ".GetId")
+            except subprocess.SubprocessError:
+                break  # Normal session shutdown or loss of its accessibility bus.
+            time.sleep(1)
+    finally:
+        stop(registry)
+
+
+def start():
+    session = os.environ.get("DBUS_SESSION_BUS_ADDRESS")
+    runtime = os.environ.get("XDG_RUNTIME_DIR", "")
+    if not session or os.path.basename(runtime) != "frametop":
+        return  # Do not autolaunch a bus or touch the host desktop.
+    os.environ.pop("AT_SPI_BUS_ADDRESS", None)
+    reply = call(session, "org.a11y.Bus", "/org/a11y/bus", "org.a11y.Bus.GetAddress")
+    address, = ast.literal_eval(reply)
+    if not isinstance(address, str) or not address.startswith("unix:"):
+        raise ValueError("org.a11y.Bus returned no local accessibility bus")
+    if call(address, DBUS, DBUS_PATH, DBUS + ".NameHasOwner", REGISTRY) == "(true,)":
+        return
+    # Activation otherwise inherits the accessibility daemon's old environment (and
+    # DBUS_SESSION_BUS_ADDRESS is the accessibility bus itself). Pin the live bus.
+    env = {key: os.environ.get(key, "") for key in (
+        "DISPLAY", "WAYLAND_DISPLAY", "XAUTHORITY", "XDG_RUNTIME_DIR",
+        "XDG_CONFIG_HOME", "DBUS_SESSION_BUS_ADDRESS")}
+    env["AT_SPI_BUS_ADDRESS"] = address
+    call(address, DBUS, DBUS_PATH, DBUS + ".UpdateActivationEnvironment", repr(env))
+    try:
+        call(address, DBUS, DBUS_PATH, DBUS + ".StartServiceByName", REGISTRY, "0")
+    except subprocess.CalledProcessError:
+        # SteamOS's launcher can select dbus-broker because we are in a user unit,
+        # but the private session bus has no systemd activation manager. Reuse its
+        # bus rather than starting another launcher/bus. Never replace an owner.
+        if call(address, DBUS, DBUS_PATH, DBUS + ".NameHasOwner", REGISTRY) == "(true,)":
+            return
+        os.environ["AT_SPI_BUS_ADDRESS"] = address
+        # registryd itself refuses to queue behind an existing registry, including
+        # races with native activation. The watcher cleans up only our own child.
+        run_registry(address, session)
+
+
+if __name__ == "__main__":
+    signal.signal(signal.SIGTERM, lambda signum, frame: sys.exit(0))
+    try:
+        start()
+    except (OSError, ValueError, SyntaxError, subprocess.SubprocessError) as error:
+        print(f"frametop: accessibility unavailable: {error}", file=sys.stderr)

session/keep-apps.sh

@@ -10,7 +10,7 @@ cg=$(systemctl --user show -p ControlGroup --value "$unit" 2>/dev/null)
 
 # The desktop's own processes stay in the unit and stop with it: the session, KWin,
 # Plasma, and the session services it started (portals, input methods, kded, wallet...).
-own='^(frametop-sessi|dbus-|startplasma|plasma|kwin|Xwayland|ksmserver|krdpserver|Xvnc|xfreerdp|ft-layout|'
+own='^(frametop-sessi|dbus-|startplasma|plasma|kwin|Xwayland|ksmserver|krdpserver|Xvnc|xfreerdp|ft-layout|ft-atspi|'
 own+='kded|kactivitymanage|kaccess|kglobalaccel|kscreen|kwalletd|ksecretd|polkit-kde|org_kde_|baloo|'
 own+='xembedsniproxy|gmenudbusmenu|DiscoverNotifie|kimpanel|ibus|xdg-|at-spi|dconf-service|fusermount|agent)'
 keep=()