Update

[ghstack-poisoned]

test/test_nn.py

@@ -2270,6 +2270,72 @@ def test_index_prob_seq(self):
         assert isinstance(seq[:2], ProbabilisticTensorDictSequential)
         assert isinstance(seq[-2:], ProbabilisticTensorDictSequential)
 
+    def test_no_warning_single_key(self):
+        # Check that there is no warning if the number of out keys is 1 and sample log prob is set
+        torch.manual_seed(0)
+        with set_composite_lp_aggregate(None):
+            mod = ProbabilisticTensorDictModule(
+                in_keys=["loc", "scale"],
+                distribution_class=torch.distributions.Normal,
+                out_keys=[("an", "action")],
+                log_prob_key="sample_log_prob",
+                return_log_prob=True,
+            )
+            td = TensorDict(loc=torch.randn(()), scale=torch.rand(()))
+            mod(td.copy())
+            mod.log_prob(mod(td.copy()))
+            mod.log_prob_key
+
+            # Don't set the key and trigger the warning
+            mod = ProbabilisticTensorDictModule(
+                in_keys=["loc", "scale"],
+                distribution_class=torch.distributions.Normal,
+                out_keys=[("an", "action")],
+                return_log_prob=True,
+            )
+            with pytest.warns(
+                DeprecationWarning, match="You are querying the log-probability key"
+            ):
+                mod(td.copy())
+                mod.log_prob(mod(td.copy()))
+                mod.log_prob_key
+
+            # add another variable, and trigger the warning
+            mod = ProbabilisticTensorDictModule(
+                in_keys=["params"],
+                distribution_class=CompositeDistribution,
+                distribution_kwargs={
+                    "distribution_map": {
+                        "dirich": torch.distributions.Dirichlet,
+                        "categ": torch.distributions.Categorical,
+                    }
+                },
+                out_keys=[("dirich", "categ")],
+                return_log_prob=True,
+            )
+            with pytest.warns(
+                DeprecationWarning, match="You are querying the log-probability key"
+            ), pytest.warns(
+                DeprecationWarning,
+                match="Composite log-prob aggregation wasn't defined explicitly",
+            ):
+                td = TensorDict(
+                    params=TensorDict(
+                        dirich=TensorDict(
+                            concentration=torch.rand(
+                                (
+                                    10,
+                                    11,
+                                )
+                            )
+                        ),
+                        categ=TensorDict(logits=torch.rand((5,))),
+                    )
+                )
+                mod(td.copy())
+                mod.log_prob(mod(td.copy()))
+                mod.log_prob_key
+
 
 class TestEnsembleModule:
     def test_init(self):