[Bugfix] Fix Higgs Audio v3 voice-clone token validation (#7065)

Signed-off-by: luozijian <luozijian0924@gmail.com>

tests/model_executor/models/higgs_audio_v3/test_higgs_audio_v3.py

@@ -892,6 +892,81 @@ class TestFeedbackMethods:
         assert r2 == {}  # Second row is all -1
 
 
+# ---- AC-3: Reference Audio Substitution Tests ----
+
+
+class TestReferenceAudioSubstitution:
+    def _make_talker(self, query_start_loc):
+        from vllm_omni.model_executor.models.higgs_audio_v3 import higgs_audio_v3_talker as mod
+
+        class FakeTalker:
+            _last_step_query_start_loc = query_start_loc
+            _apply_ref_audio_substitution = mod.HiggsAudioV3TalkerForConditionalGeneration._apply_ref_audio_substitution
+
+            @staticmethod
+            def multimodal_embedding(codes):
+                return codes.to(torch.float32)
+
+        return FakeTalker()
+
+    @staticmethod
+    def _reference_info():
+        return [
+            {
+                "audio_input_ids": torch.tensor([[5], [7]], dtype=torch.long),
+                "audio_input_ids_mask": torch.tensor([True, True]),
+                "audio_placeholder_positions": torch.tensor([1, 2]),
+            }
+        ]
+
+    def test_valid_placeholder_tokens_are_replaced_from_explicit_positions(self):
+        talker = self._make_talker(torch.tensor([0, 4]))
+        hidden_states = torch.zeros(4, 1)
+        input_ids = torch.tensor([1, 151702, 151702, 2])
+        positions = torch.arange(4)
+
+        result = talker._apply_ref_audio_substitution(
+            hidden_states,
+            input_ids,
+            positions,
+            self._reference_info(),
+        )
+
+        assert result[:, 0].tolist() == [0.0, 5.0, 7.0, 0.0]
+
+    def test_chunked_prefill_selects_code_by_absolute_prompt_position(self):
+        talker = self._make_talker(torch.tensor([0, 1]))
+        hidden_states = torch.zeros(1, 1)
+        input_ids = torch.tensor([151702])
+        positions = torch.tensor([2])
+
+        result = talker._apply_ref_audio_substitution(
+            hidden_states,
+            input_ids,
+            positions,
+            self._reference_info(),
+        )
+
+        assert result[:, 0].tolist() == [7.0]
+
+    def test_legacy_negative_placeholder_tokens_remain_supported(self):
+        talker = self._make_talker(torch.tensor([0, 4]))
+        hidden_states = torch.zeros(4, 1)
+        input_ids = torch.tensor([1, -100, -100, 2])
+        positions = torch.arange(4)
+        reference_info = self._reference_info()
+        reference_info[0].pop("audio_placeholder_positions")
+
+        result = talker._apply_ref_audio_substitution(
+            hidden_states,
+            input_ids,
+            positions,
+            reference_info,
+        )
+
+        assert result[:, 0].tolist() == [0.0, 5.0, 7.0, 0.0]
+
+
 # ---- AC-6: Audio Feedback Method Tests ----
 
 
@@ -1545,6 +1620,23 @@ class TestPromptBuilder:
         assert 151703 not in ids  # <|ref_audio|>
         assert 151704 not in ids  # <|ref_text|>
 
+    def test_voice_clone_prompt_is_vocab_valid_for_engine(self):
+        from vllm_omni.model_executor.models.higgs_audio_v3.higgs_audio_v3_tokenizer import (
+            HiggsAudioV3TokenizerAdapter,
+        )
+
+        adapter = HiggsAudioV3TokenizerAdapter(self._make_mock_tokenizer())
+        prompt_ids = adapter.build_prompt("Hello", num_ref_tokens=2)
+
+        engine_prompt_ids, placeholder_positions = adapter.prepare_prompt_for_engine(prompt_ids)
+
+        assert min(prompt_ids) < 0
+        assert min(engine_prompt_ids) >= 0
+        assert placeholder_positions.tolist() == [2, 3]
+        filler_ids = [engine_prompt_ids[index] for index in placeholder_positions.tolist()]
+        assert filler_ids == [adapter.tts_id] * 2
+        assert adapter.audio_id not in filler_ids
+
 
 class TestVoiceCloneReferenceCache:
     def test_audio_tokenizer_dir_env_accepts_parent_or_subdir(self, tmp_path, monkeypatch):