[Bugfix] Fix Cohere2MoeConfig import crash from huggingface_hub @strict (#31769)

test/registered/unit/configs/test_cohere2_moe_config.py

@@ -0,0 +1,60 @@
+"""Regression tests for Cohere2MoeConfig import (sgl-project/sglang#28233).
+
+Before the fix, applying ``huggingface_hub.dataclasses.strict`` to
+``Cohere2MoeConfig`` — which is not a stdlib ``@dataclass`` — raised
+``StrictDataclassDefinitionError`` at *import* time on
+``transformers==5.3.0`` + ``huggingface_hub==1.9.0``, which meant that
+``sglang.srt.configs`` could not be imported at all.
+"""
+
+import unittest
+
+from sglang.test.ci.ci_register import register_cpu_ci
+from sglang.test.test_utils import CustomTestCase
+
+register_cpu_ci(est_time=5, suite="base-a-test-cpu")
+
+
+class TestCohere2MoeConfig(CustomTestCase):
+    def test_configs_package_imports(self):
+        """Importing the configs package must not crash at module load."""
+        import sglang.srt.configs  # noqa: F401
+
+    def test_derived_defaults_num_key_value_heads(self):
+        """``num_key_value_heads`` defaults to ``num_attention_heads``."""
+        from sglang.srt.configs.cohere2_moe import Cohere2MoeConfig
+
+        cfg = Cohere2MoeConfig()
+        self.assertEqual(cfg.num_key_value_heads, cfg.num_attention_heads)
+
+    def test_derived_defaults_layer_types(self):
+        """``layer_types`` is auto-derived to one entry per hidden layer."""
+        from sglang.srt.configs.cohere2_moe import Cohere2MoeConfig
+
+        cfg = Cohere2MoeConfig()
+        self.assertEqual(len(cfg.layer_types), cfg.num_hidden_layers)
+
+    def test_pretrained_config_kwargs_forwarded(self):
+        """Extra kwargs must flow through ``PreTrainedConfig.__init__``."""
+        from sglang.srt.configs.cohere2_moe import Cohere2MoeConfig
+
+        cfg = Cohere2MoeConfig(foo="bar")
+        cfg_dict = cfg.to_dict()
+        self.assertEqual(cfg_dict["model_type"], "cohere2_moe")
+        self.assertEqual(cfg_dict["foo"], "bar")
+
+    def test_use_cache_false_preserved(self):
+        """``use_cache=False`` must survive ``super().__init__``.
+
+        ``PreTrainedConfig.__init__`` re-assigns ``self.use_cache`` from its
+        own keyword; if the subclass does not forward the caller's value,
+        ``use_cache=False`` silently reverts to the base default ``True``.
+        """
+        from sglang.srt.configs.cohere2_moe import Cohere2MoeConfig
+
+        cfg = Cohere2MoeConfig(use_cache=False)
+        self.assertFalse(cfg.use_cache)
+
+
+if __name__ == "__main__":
+    unittest.main()