Devices: fixes from review round 11

- A headset set up while a bare alias is in use doesn't take over by itself;
  a login change from ~/.ssh/config waits for running installs.
- Saving a headset writes only the login fields that changed, and only if the
  block still holds the old ones.
- SSH, SFTP, power and remote desktop open with the same headset and address
  as every other command, and refuse when there's no address.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/test_link.py

@@ -263,6 +263,36 @@ class Connecting(unittest.TestCase):
         self.assertEqual(self.link.active_device()["alias"], "frame-bare")
         self.assertEqual(self.routes[-1], ("frame-bare", []))
 
+    def test_setup_changing_the_login_waits_for_installs(self):
+        d = self.device("localhost")
+        self.hosts({"localhost": "ok"})
+        self.link.connect(["start"])
+        cfg = self.dir / "ssh" / "config"
+        cfg.write_text("# >>> steam-frame (frame-t) >>>\nHost frame-t\n  HostName localhost\n  User steamos\n"
+                       f"  Port {self.port}\nHost *\n# <<< steam-frame (frame-t) <<<\n")
+        self.link.watch_config()  # the block's login is recorded
+        routes = len(self.routes)
+        cfg.write_text(cfg.read_text().replace("User steamos", "User deck"))
+        running = [1]
+        self.link.work = lambda: running[0]
+        self.link.config_mtime = None
+        self.link.watch_config()
+        self.assertEqual(len(self.routes), routes)  # an install is running: not yet
+        running[0] = 0
+        self.link.watch_config()
+        self.assertIn("User=deck", self.routes[-1][1])
+
+    def test_a_rename_leaves_the_login_in_the_config_alone(self):
+        d = self.device("localhost")
+        cfg = self.dir / "ssh" / "config"
+        cfg.write_text("# >>> steam-frame (frame-t) >>>\nHost frame-t\n  HostName localhost\n  User deck\n"
+                       "Host *\n# <<< steam-frame (frame-t) <<<\n")  # setup wrote a new user, not yet imported
+        fl.devices_action(self.link, {"action": "update", "id": d["id"], "name": "Desk"}, None)
+        self.assertIn("User deck", cfg.read_text())
+        out = fl.devices_action(self.link, {"action": "update", "id": d["id"], "port": 2200}, None)
+        self.assertIn("User deck", cfg.read_text())  # changed meanwhile: left as it is
+        self.assertIn("left as it is", out["message"])
+
     def test_probes_from_an_earlier_attempt_leave_the_new_rows_alone(self):
         self.link.state.update(attempt=2, probes=[{"host": "b", "state": "waiting"}])
         self.link.probe_update(0, 1, state="answered", ip="10.0.0.2")

ui/frame_host.py

@@ -257,9 +257,9 @@ def open_steam_link():
     return "Steam Link isn't installed; opened its download page"
 
 
-def open_rdp(alias):
-    """Remote desktop to the Frame's xrdp (user steamos)."""
-    host = ssh_hostname(alias)
+def open_rdp(alias, host=None):
+    """Remote desktop to the Frame's xrdp (user steamos), at `host` or where the alias points."""
+    host = host or ssh_hostname(alias)
     if MAC:
         if subprocess.run(["open", "-a", "Windows App"], capture_output=True).returncode == 0:
             return "Opened Windows App"

ui/frame_link.py

@@ -153,6 +153,9 @@ class Link:
     def __init__(self, registry, *, env_alias, mux_base, control, apply, explain):
         self.reg = registry
         self.override = env_alias       # FRAME_ALIAS, if set: the headset this server starts on
+        self.work_lock = threading.Lock()  # the server's: held, no install starts (see server.working)
+        self.work = lambda: 0              # how many installs are running
+        self.deferred = False              # a login change from ~/.ssh/config waiting for them
         self.session_alias = env_alias  # ...and stays selectable after switching away
         self.mux_base = list(mux_base)  # ["ssh", "-o", "BatchMode=yes", ControlPath...]
         self.control = control          # ControlPath, or None where ssh can't share connections
@@ -407,11 +410,19 @@ class Link:
         if mtime != self.config_mtime:
             self.config_mtime = mtime
             before = self.active_device()
+            if before.get("transient") and not before.get("none") and self.routed is not None:
+                # A bare alias is in use: a headset set up now doesn't take over by itself.
+                self.override = self.override or before["alias"]
             if self.reg.sync_from_config():
                 self.devices_changed()
                 after = self.active_device()
                 if (before.get("user"), before.get("port")) != (after.get("user"), after.get("port")):
-                    self.invalidate()  # Set Up Connection changed the active headset's login
+                    self.deferred = True  # Set Up Connection changed the active headset's login
+        if self.deferred:
+            with self.work_lock:  # not while an install runs: it reads the route step by step
+                if not self.work():
+                    self.deferred = False
+                    self.invalidate()
 
     def refresh_network(self):
         net = frame_network.current_network(self.last_fp)
@@ -937,13 +948,21 @@ def devices_action(link, body, open_setup, busy=lambda: 0):
     elif action == "update":
         before = reg.get(did)
         d = reg.update_device(did, name=body.get("name"), user=body.get("user"), port=body.get("port"))
-        if is_active and (d["user"], d["port"]) != (before["user"], before["port"]):
+        login_changed = (d["user"], d["port"]) != (before["user"], before["port"])
+        if is_active and login_changed:
             link.invalidate()  # before anything else can fail: the old login mustn't stay in use
-        try:
-            frame_devices.rewrite_block(d["alias"], user=d["user"], port=d["port"])
-        except OSError as e:
-            raise frame_devices.DeviceError(f"Saved, but couldn't update ~/.ssh/config: {e}")
         msg = f"Saved {d['name']}"
+        if login_changed:
+            # Only what changed, and only if the block still says what it did: Set Up
+            # Connection may have written a new login meanwhile, which then stands.
+            try:
+                if not frame_devices.rewrite_block(d["alias"], user=d["user"], port=d["port"],
+                                                   expect={"user": before["user"], "port": before["port"]}) \
+                        and any(b["alias"] == d["alias"] and (b["user"], b["port"]) != (d["user"], d["port"])
+                                for b in frame_devices.parse_blocks(frame_devices.read_config())):
+                    msg += "; ~/.ssh/config changed meanwhile, so it was left as it is"
+            except OSError as e:
+                raise frame_devices.DeviceError(f"Saved, but couldn't update ~/.ssh/config: {e}")
     elif action == "remove":
         if not body.get("config") and len(reg.devices()) == 1 and reg.get(did)["alias"] in {
                 b["alias"] for b in frame_devices.parse_blocks(frame_devices.read_config())}:

ui/server.py

@@ -580,19 +580,25 @@ def open_thing(body):
         if what in ("reboot", "poweroff", "suspend"):
             return power(what, body.get("password"))
         raise Failure("open that from the app", 400)
+    # The headset and address in use, as every other command gets them (one snapshot).
+    with _route_lock:
+        alias, opts = FRAME, list(HOST_OPTS)
+    host = next((o.split("=", 1)[1].replace("%%", "%") for o in opts if o.startswith("HostName=")), None)
+    if what in ("terminal", "reboot", "poweroff", "suspend", "rdp", "sftp") and host and host.endswith(".invalid"):
+        raise Failure("No headset address to use: add one on the Devices tab", 400)
     try:
         if what == "terminal":
-            return {"message": f"Opened an SSH session in {terminal(['ssh', FRAME])}"}
+            return {"message": f"Opened an SSH session in {terminal(['ssh', *opts, alias])}"}
         if what in ("reboot", "poweroff", "suspend"):
             # logind answers "challenge" over SSH, so sudo (and the password) is needed.
-            where = terminal(["ssh", "-t", FRAME, "sudo", "systemctl", what])
+            where = terminal(["ssh", "-t", *opts, alias, "sudo", "systemctl", what])
             return {"message": f"Confirm with the Developer Mode password in {where} to {what}"}
         if what == "steamlink":
             return {"message": frame_host.open_steam_link()}
         if what == "rdp":
-            return {"message": frame_host.open_rdp(FRAME)}
+            return {"message": frame_host.open_rdp(alias, host)}
         if what == "sftp":
-            return {"message": f"Opened an SFTP session in {terminal(['sftp', FRAME])}"}
+            return {"message": f"Opened an SFTP session in {terminal(['sftp', *opts, alias])}"}
         if what == "shots":
             SHOTS_DIR.mkdir(parents=True, exist_ok=True)
             frame_host.open_path(SHOTS_DIR)
@@ -1659,6 +1665,7 @@ def main():
     if not LOCAL:
         LINK = frame_link.Link(frame_devices.Registry(), env_alias=FRAME if FRAME_FROM_ENV else None,
                                mux_base=MUX_BASE, control=CONTROL, apply=route, explain=unreachable)
+        LINK.work_lock, LINK.work = _work_lock, lambda: _work[0]
         LINK.start()
     if not frame_host.WINDOWS:
         signal.signal(signal.SIGTERM, lambda *_: (_ for _ in ()).throw(KeyboardInterrupt))