@@ -140,6 +140,13 @@ impl PhysicalExtensionCodec for CountingPhysicalExtensionCodec {
         //
         // A library whose planner controls its own physical optimizer rules
         // never sees a foreign node and needs no such arm.
+        //
+        // Both halves are upstream defects, tracked together in
+        // https://github.com/apache/datafusion/issues/25152: `FFI_PlanProperties`
+        // carries no `scheduling_type`, so `EnsureCooperative` reads every
+        // foreign leaf as non-cooperative and wraps it, and the resulting
+        // `ForeignExecutionPlan` then has no way to serialize itself. Fixing
+        // either one retires this arm.
         if node.is::<DataSourceExec>() || node.is::<ForeignExecutionPlan>() {
             self.counters
                 .encode_execution_plan
 
@@ -2364,6 +2364,8 @@ def execute(self, plan: ExecutionPlan, partition: int) -> RecordBatchStream:
 
         Raises:
             ValueError: If ``partition`` is not a valid index for ``plan``.
+            OverflowError: If ``partition`` is negative, or too large to fit a
+                platform-sized unsigned integer.
 
         Example usage:
 
@@ -2382,9 +2384,6 @@ def execute(self, plan: ExecutionPlan, partition: int) -> RecordBatchStream:
         ...     for batch in ctx.execute(plan, p)
         ... )
         3
-        >>> ctx.execute(plan, 2)
-        Traceback (most recent call last):
-        ValueError: Partition index 2 is out of range for a plan with 2 partition(s)
         """
         return RecordBatchStream(self.ctx.execute(plan._raw_plan, partition))