[recipe, model] fix: resolve 26.08 model workflow regressions (#4994)

Signed-off-by: yaoyu-33 <yaoyu.094@gmail.com>

Author: yaoyu-33

examples/models/nemotron/nemotron_3/nano/slurm_sft.sh

@@ -155,7 +155,7 @@ for CONFIG in "${PARALLELISM_CONFIGS[@]}"; do
         model.seq_length=$SEQ_LENGTH"
 
     CMD="uv run --no-sync python scripts/training/run_recipe.py"
-    CMD="$CMD --recipe ${MODEL_NAME}_finetune_config"
+    CMD="$CMD --recipe ${MODEL_NAME}_sft_config"
     CMD="$CMD $CLI_OVERRIDES"
 
     echo "Executing command..."

examples/models/qwen/qwen2_audio/sft.sh

@@ -77,7 +77,7 @@ for par_config in "${PARALLELISM_CONFIGS[@]}"; do
     echo "  run_recipe.py | TP=${TP}, PP=${PP}"
     echo "============================================================"
     uv run --no-sync python -m torch.distributed.run --nproc_per_node=${NPROC} scripts/training/run_recipe.py \
-        --recipe qwen2_audio_7b_finetune_config \
+        --recipe qwen2_audio_7b_sft_config \
         --step_func audio_lm_step \
         checkpoint.pretrained_checkpoint=$PRETRAINED_CHECKPOINT \
         checkpoint.save=${WORKSPACE}/exp/${MODEL_NAME}_sft_tp${TP}_pp${PP} \

src/megatron/bridge/models/hf_pretrained/base.py

@@ -211,7 +211,26 @@ def save_artifacts(
         for name in self.OPTIONAL_ARTIFACTS:
             artifact = getattr(self, name, None)
             if artifact is not None and hasattr(artifact, "save_pretrained"):
-                artifact.save_pretrained(save_path)
+                try:
+                    artifact.save_pretrained(save_path)
+                except ValueError:
+                    if name != "generation_config":
+                        raise
+
+                    source_path = original_source_path or getattr(self, "model_name_or_path", None)
+                    copied_files = []
+                    if source_path is not None:
+                        copied_files = self._copy_custom_modeling_files(
+                            source_path=source_path,
+                            target_path=save_path,
+                            file_patterns=["generation_config.json"],
+                        )
+                    if "generation_config.json" not in copied_files:
+                        raise
+                    logger.warning(
+                        "GenerationConfig.save_pretrained() rejected the source artifact; "
+                        "preserved the original generation_config.json instead."
+                    )
 
         # Download/copy additional files if specified
         if additional_files:

tests/unit_tests/doc_consistency/test_readme_consistency.py

@@ -211,6 +211,37 @@ def test_model_examples_use_current_run_recipe_arguments():
     assert not offenders, f"Model examples use removed run_recipe.py arguments: {offenders}"
 
 
+def test_nemotron_and_qwen2_audio_finetune_launchers_use_exported_recipes():
+    """SFT and PEFT example recipes must match their launcher-visible aliases."""
+    launcher_expectations = {
+        MODEL_EXAMPLES / "nemotron" / "nemotron_3" / "nano" / "slurm_sft.sh": (
+            "${MODEL_NAME}_sft_config",
+            "nemotron_3_nano_finetune_config",
+        ),
+        MODEL_EXAMPLES / "nemotron" / "nemotron_3" / "nano" / "slurm_peft.sh": (
+            "${MODEL_NAME}_peft_config",
+            "nemotron_3_nano_finetune_config",
+        ),
+        MODEL_EXAMPLES / "qwen" / "qwen2_audio" / "sft.sh": (
+            "qwen2_audio_7b_sft_config",
+            "qwen2_audio_7b_finetune_config",
+        ),
+    }
+    for path, (expected_recipe, stale_recipe) in launcher_expectations.items():
+        text = _read(path)
+        assert expected_recipe in text
+        assert stale_recipe not in text
+
+    defined_recipes = _defined_recipe_names()
+    expected_recipes = {
+        "nemotron_3_nano_sft_config",
+        "nemotron_3_nano_peft_config",
+        "qwen2_audio_7b_sft_config",
+        "qwen2_audio_7b_peft_config",
+    }
+    assert expected_recipes <= defined_recipes
+
+
 def test_dclm_readme_megatron_lm_tool_path():
     """The DCLM tutorial points at the bundled submodule tool path (bug 6)."""
     gitmodules = _read(REPO_ROOT / ".gitmodules")

tests/unit_tests/models/hf_pretrained/test_base.py

@@ -20,6 +20,7 @@
 from pathlib import Path
 from unittest.mock import Mock, patch
 
+import pytest
 from transformers.configuration_utils import PretrainedConfig
 
 
@@ -274,6 +275,42 @@ def test_save_artifacts_without_model_name_or_path():
         print("✅ test_save_artifacts_without_model_name_or_path passed")
 
 
+def test_save_artifacts_preserves_rejected_source_generation_config():
+    """Test invalid-but-loadable source generation metadata is preserved verbatim."""
+    with tempfile.TemporaryDirectory() as tmp_dir:
+        tmp_path = Path(tmp_dir)
+        source_dir = tmp_path / "source"
+        source_dir.mkdir()
+        source_generation_config = '{"do_sample": false, "temperature": 0.000001}\n'
+        (source_dir / "generation_config.json").write_text(source_generation_config)
+        target_dir = tmp_path / "target"
+
+        base = MockPreTrainedBase(model_name_or_path=str(source_dir))
+        base._config = Mock(save_pretrained=Mock())
+        base._generation_config = Mock()
+        base._generation_config.save_pretrained.side_effect = ValueError("invalid generation config")
+
+        base.save_artifacts(target_dir)
+
+        assert (target_dir / "generation_config.json").read_text() == source_generation_config
+
+
+def test_save_artifacts_reraises_generation_config_error_without_source_file():
+    """Test generation config save errors are not hidden without a source artifact."""
+    with tempfile.TemporaryDirectory() as tmp_dir:
+        tmp_path = Path(tmp_dir)
+        source_dir = tmp_path / "source"
+        source_dir.mkdir()
+
+        base = MockPreTrainedBase(model_name_or_path=str(source_dir))
+        base._config = Mock(save_pretrained=Mock())
+        base._generation_config = Mock()
+        base._generation_config.save_pretrained.side_effect = ValueError("invalid generation config")
+
+        with pytest.raises(ValueError, match="invalid generation config"):
+            base.save_artifacts(tmp_path / "target")
+
+
 def test_copy_handles_permission_errors():
     """Test that copy failures are handled gracefully."""
     with tempfile.TemporaryDirectory() as tmp_dir: