test(attention): cover the sdpa escape hatches

bypass_sdpa_hijacks and llm_context restore the pinned original over the
router and put the router back, including when the body raises. Captioners
and detailers run inside them, so the router must be removable.

test/test-attention-router.py

@@ -19,6 +19,8 @@ Covers:
   callback and the modular pre-hook, per-pass resets, the in-place step buffer, role scopes
 - telemetry: the route observer, the chain string recorded in torch_info, report(), and the
   SD_ATTN_DEBUG route log deduplication
+- the escape hatches captioners and detailers depend on: bypass_sdpa_hijacks and llm_context
+  restore the original sdpa over the router, and put the router back even when the body raises
 
 No running server required. Nothing is moved to the accelerator.
 
@@ -411,6 +413,35 @@ def test_debug_observe_logs_each_route_once():
     return True
 
 
+def test_escape_hatch_bypasses_the_router():
+    from modules import devices
+    saved_sdpa = torch.nn.functional.scaled_dot_product_attention
+    saved_plan = attention_router.current_plan
+    saved_original = devices.sdpa_original
+    try:
+        devices.sdpa_original = sdpa_stub # what set_sdpa_params pinned before building the chain
+        attention.install_router(['SDNQ attention'], attention.Platform(backend='cuda'), sdpa_stub, stub_registry())
+        router = torch.nn.functional.scaled_dot_product_attention
+        assert router is not sdpa_stub
+        with devices.bypass_sdpa_hijacks():
+            assert torch.nn.functional.scaled_dot_product_attention is sdpa_stub # captioners and detailers run here
+        assert torch.nn.functional.scaled_dot_product_attention is router
+        with devices.llm_context():
+            assert torch.nn.functional.scaled_dot_product_attention is sdpa_stub
+        assert torch.nn.functional.scaled_dot_product_attention is router
+        try:
+            with devices.bypass_sdpa_hijacks():
+                raise RuntimeError('captioner failed')
+        except RuntimeError:
+            pass
+        assert torch.nn.functional.scaled_dot_product_attention is router, 'the chain must survive a failure inside the bypass'
+    finally:
+        devices.sdpa_original = saved_original
+        torch.nn.functional.scaled_dot_product_attention = saved_sdpa
+        attention_router.current_plan = saved_plan
+    return True
+
+
 def test_reapply_options_cover_declared_backend_options():
     from modules import shared
     names = attention.reapply_options()
@@ -454,6 +485,7 @@ def run_all():
         test_install_router_records_the_chain,
         test_debug_observe_logs_each_route_once,
         test_reapply_options_cover_declared_backend_options,
+        test_escape_hatch_bypasses_the_router,
     ]:
         run_test(cat, fn)