[mics][fix] Deprecate legacy _default_compute_score API and fix ray utils test (#1729)

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### What does this PR do?

Handle comments after #1397 being merged:

1. Add back `_default_compute_score` API and mark it as deprecated;
2. Fix a broken ci test `ray_utils_test` on `parallel_put`;

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- [ ] Add `[BREAKING]` to the PR title if it breaks any API.
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- [ ] Add CI test(s) if necessary.

---------

Signed-off-by: Hongpeng Guo <[email protected]>

Author: hongpeng-guo

tests/ray_cpu/test_ray_utils.py

@@ -36,8 +36,8 @@ def test_parallel_put_basic(init_ray):
 
 def test_parallel_put_empty(init_ray):
     data = []
-    refs = parallel_put(data)
-    assert len(refs) == 0
+    with pytest.raises(AssertionError):
+        _ = parallel_put(data)
 
 
 def test_parallel_put_workers(init_ray):

verl/utils/ray_utils.py

@@ -34,6 +34,7 @@ def parallel_put(data_list: List[Any], max_workers: Optional[int] = None):
         List[ray.ObjectRef]: A list of Ray object references corresponding to the input data_list,
                              maintaining the original order.
     """
+    assert len(data_list) > 0, "data_list must not be empty"
 
     def put_data(index, data):
         return index, ray.put(data)

verl/utils/reward_score/__init__.py

@@ -13,6 +13,8 @@
 # limitations under the License.
 # from . import gsm8k, math, prime_math, prime_code
 
+from verl.utils.import_utils import deprecated
+
 
 def default_compute_score(data_source, solution_str, ground_truth, extra_info=None, sandbox_fusion_url=None, concurrent_semaphore=None):
     """Compute the score for a given solution based on the data source.
@@ -88,4 +90,12 @@ def default_compute_score(data_source, solution_str, ground_truth, extra_info=No
         return float(res[0])
 
 
+@deprecated("verl.utils.reward_score.default_compute_score")
+def _default_compute_score(data_source, solution_str, ground_truth, extra_info=None, sandbox_fusion_url=None, concurrent_semaphore=None):
+    """
+    Legacy function API to be deprecated. Please use `default_compute_score` instead.
+    """
+    return default_compute_score(data_source, solution_str, ground_truth, extra_info, sandbox_fusion_url, concurrent_semaphore)
+
+
 __all__ = ["default_compute_score"]