correct sampled variables in sample_prior_predictive log call & add r…

…eturn type overloads

pymc/sampling/forward.py

@@ -22,6 +22,7 @@
     Any,
     TypeAlias,
     cast,
+    overload,
 )
 
 import numpy as np
@@ -360,6 +361,28 @@ def observed_dependent_deterministics(model: Model, extra_observeds=None):
     ]
 
 
+@overload
+def sample_prior_predictive(
+    draws: int = 500,
+    model: Model | None = None,
+    var_names: Iterable[str] | None = None,
+    random_seed: RandomState = None,
+    return_inferencedata: bool = True,
+    idata_kwargs: dict | None = None,
+    compile_kwargs: dict | None = None,
+    samples: int | None = None,
+) -> InferenceData: ...
+@overload
+def sample_prior_predictive(
+    draws: int = 500,
+    model: Model | None = None,
+    var_names: Iterable[str] | None = None,
+    random_seed: RandomState = None,
+    return_inferencedata: bool = False,
+    idata_kwargs: dict | None = None,
+    compile_kwargs: dict | None = None,
+    samples: int | None = None,
+) -> dict[str, np.ndarray]: ...
 def sample_prior_predictive(
     draws: int = 500,
     model: Model | None = None,
@@ -449,7 +472,7 @@ def sample_prior_predictive(
     )
 
     # All model variables have a name, but mypy does not know this
-    _log.info(f"Sampling: {sorted(volatile_basic_rvs, key=lambda var: var.name)}")  # type: ignore[arg-type, return-value]
+    _log.info(f"Sampling: {sorted(vars_to_sample, key=lambda var: var.name)}")  # type: ignore[arg-type, return-value]
     values = zip(*(sampler_fn() for i in range(draws)))
 
     data = {k: np.stack(v) for k, v in zip(names, values)}