Recover router availability after failed profile switch

dev/test_router_support.py

@@ -24,6 +24,7 @@ from router_support import (  # noqa: E402
     load_profile_registry,
 )
 from ai_profile_router import (  # noqa: E402
+    STATE,
     _cap_chat_generation,
     _context_matches,
     _inject_global_system_policy,
@@ -31,6 +32,7 @@ from ai_profile_router import (  # noqa: E402
     _normalize_chat_images,
     _normalize_llamacpp_reasoning,
     _request_has_image,
+    switch_profile,
 )
 
 
@@ -94,6 +96,16 @@ class ProfileRegistryTests(unittest.TestCase):
         self.assertFalse(_context_matches(80000, 76800))
         self.assertFalse(_context_matches(80000, 82000))
 
+    def test_ready_profile_clears_stale_unavailable_flag(self) -> None:
+        with STATE.avail_lock:
+            STATE.qwen_unavailable = True
+        status = {"reachable": True, "model": "qwen-medium", "ctx": 160000}
+        with patch("ai_profile_router.current_profile", return_value="medium"), \
+                patch("ai_profile_router.upstream_status", return_value=status):
+            switch_profile("medium")
+        with STATE.avail_lock:
+            self.assertFalse(STATE.qwen_unavailable)
+
 
 class ChatImageInputTests(unittest.TestCase):
     def test_small_png_data_url_is_accepted(self) -> None:

router/ai_profile_router.py

@@ -698,6 +698,11 @@ def switch_profile(profile: str, implicit: bool = False) -> None:
             up = upstream_status()
             ready = _profile_is_ready(profile, up)
             if cur == profile and ready:
+                # A previous failed switch can leave the in-memory availability
+                # flag set even though the controller and llama.cpp have since
+                # recovered.  The semantic readiness check above is authoritative,
+                # so clear the stale flag before returning.
+                _set_qwen_unavailable(False)
                 log.info("Profil %s ist bereits aktiv", profile)
                 return
             # Qwen wird neu geladen/gewechselt → für Chats nicht verfügbar.