Better guesses for why logp has RVs

pymc/logprob/basic.py

@@ -400,13 +400,6 @@ def icdf(rv: TensorVariable, value: TensorLike, warn_rvs=None, **kwargs) -> Tens
         return expr
 
 
-RVS_IN_JOINT_LOGP_GRAPH_MSG = (
-    "Random variables detected in the logp graph: %s.\n"
-    "This can happen when DensityDist logp or Interval transform functions reference nonlocal variables,\n"
-    "or when not all rvs have a corresponding value variable."
-)
-
-
 def conditional_logp(
     rv_values: dict[TensorVariable, TensorVariable],
     warn_rvs=None,
@@ -563,7 +556,11 @@ def conditional_logp(
     if warn_rvs:
         rvs_in_logp_expressions = _find_unallowed_rvs_in_graph(logprobs)
         if rvs_in_logp_expressions:
-            warnings.warn(RVS_IN_JOINT_LOGP_GRAPH_MSG % rvs_in_logp_expressions, UserWarning)
+            warnings.warn(
+                f"Random variables detected in the logp graph: {rvs_in_logp_expressions}.\n"
+                "This can happen when not all random variables have a corresponding value variable.",
+                UserWarning,
+            )
 
     return values_to_logprobs
 
@@ -611,7 +608,11 @@ def transformed_conditional_logp(
 
     rvs_in_logp_expressions = _find_unallowed_rvs_in_graph(logp_terms_list)
     if rvs_in_logp_expressions:
-        raise ValueError(RVS_IN_JOINT_LOGP_GRAPH_MSG % rvs_in_logp_expressions)
+        raise ValueError(
+            f"Random variables detected in the logp graph: {rvs_in_logp_expressions}.\n"
+            "This can happen when mixing variables from different models, "
+            "or when CustomDist logp or Interval transform functions reference nonlocal variables."
+        )
 
     return logp_terms_list