fix: clear stale modem dashboard state on config change (#186)

Author: itsDNNS

app/main.py

@@ -212,6 +212,7 @@ def start_polling():
         if poll_thread and poll_thread.is_alive():
             poll_stop.set()
             poll_thread.join(timeout=10)
+        web.reset_modem_state()
         poll_stop = threading.Event()
         poll_thread = threading.Thread(
             target=polling_loop, args=(config_mgr, storage, poll_stop), daemon=True

app/web.py

@@ -581,6 +581,21 @@ def get_state() -> dict:
         return dict(_state)
 
 
+def reset_modem_state():
+    """Clear modem-specific dashboard state before switching drivers.
+
+    Keeps unrelated collector data like speedtest/weather cache intact so
+    the dashboard only drops the modem-derived sections while a new poll
+    is starting.
+    """
+    with _state_lock:
+        _state["analysis"] = None
+        _state["last_update"] = None
+        _state["error"] = None
+        _state["connection_info"] = None
+        _state["device_info"] = None
+
+
 @app.route("/sw.js")
 def service_worker():
     return send_from_directory(app.static_folder, "sw.js", mimetype="application/javascript")
@@ -733,4 +748,3 @@ def add_security_headers(response):
 # ── Blueprint Registration ──
 from .blueprints import register_blueprints
 register_blueprints(app)
-

tests/test_web.py

@@ -3,7 +3,7 @@
 import io
 import json
 import pytest
-from app.web import app, update_state, init_config, init_storage
+from app.web import app, update_state, init_config, init_storage, reset_modem_state, get_state
 from app.config import ConfigManager
 from app.storage import SnapshotStorage
 from app.modules.bnetz.storage import BnetzStorage
@@ -208,6 +208,24 @@ def test_health_ok(self, client, sample_analysis):
         assert data["status"] == "ok"
         assert data["docsis_health"] == "good"
 
+    def test_reset_modem_state_clears_stale_dashboard_data(self, client, sample_analysis):
+        update_state(
+            analysis=sample_analysis,
+            device_info={"model": "Generic Router"},
+            connection_info={"connection_type": "generic"},
+            speedtest_latest={"download_mbps": 230.5},
+        )
+
+        reset_modem_state()
+        state = get_state()
+
+        assert state["analysis"] is None
+        assert state["device_info"] is None
+        assert state["connection_info"] is None
+        assert state["last_update"] is None
+        assert state["error"] is None
+        assert state["speedtest_latest"] == {"download_mbps": 230.5}
+
 
 class TestExportEndpoint:
     def test_export_no_data(self, client):