[Bugfix] Reject /v1/completions for thinker+talker models when --trust-remote-code is unset (#5525)

Signed-off-by: ChoHee15 <cc5281@126.com>

tests/utils/test_tracking_parser.py

@@ -219,6 +219,46 @@ def test_store_true_explicit():
     assert ns.verbose is True
 
 
+def test_unset_trust_remote_code_falls_back_to_engine_default_none():
+    """Regression guard for issue #5495 (the CLI-plumbing half).
+
+    The CI test ``test_completions_rejected_for_thinker_talker`` does NOT pass
+    ``--trust-remote-code``. Because it is a ``store_true`` flag, an omitted
+    value is dropped from ``get_explicit_kwargs_dict()`` (it is not user-typed),
+    so it is never forwarded to ``AsyncOmni(**kwargs)`` and the engine falls back
+    to ``AsyncOmniEngine.__init__``'s default of ``None`` — NOT argparse's
+    ``False``. That ``None`` is what used to break endpoint-restriction
+    resolution (see ``TestQwen3OmniPipeline.
+    test_endpoint_restrictions_survive_unset_trust_remote_code``).
+
+    This test locks in the "CI does not pass the flag => effective value is
+    None" premise so a future refactor cannot silently change it.
+    """
+    import inspect
+
+    from vllm_omni.engine.async_omni_engine import AsyncOmniEngine
+
+    p = TrackingArgumentParser()
+    # Mirror how --trust-remote-code is registered upstream (store_true).
+    p.add_argument("--trust-remote-code", action="store_true")
+
+    # Scenario A: CI — flag omitted.
+    ns = p.parse_args([])
+    assert "trust_remote_code" not in ns.explicit_keys
+    kwargs = ns.get_explicit_kwargs_dict()
+    assert "trust_remote_code" not in kwargs
+    engine_default = inspect.signature(AsyncOmniEngine.__init__).parameters["trust_remote_code"].default
+    assert engine_default is None
+    effective = kwargs.get("trust_remote_code", engine_default)
+    assert effective is None  # <- the value that reached the buggy restriction path
+
+    # Scenario B: flag passed (what earlier repros used) => True, restrictions fine.
+    ns2 = p.parse_args(["--trust-remote-code"])
+    assert "trust_remote_code" in ns2.explicit_keys
+    kwargs2 = ns2.get_explicit_kwargs_dict()
+    assert kwargs2.get("trust_remote_code", engine_default) is True
+
+
 def test_store_false_default():
     """Ensure that store false is handled correctly when omitted."""
     p = TrackingArgumentParser()