diff --git a/daft/execution/execution_step.py b/daft/execution/execution_step.py
index 8461882da1..a41ec19da4 100644
--- a/daft/execution/execution_step.py
+++ b/daft/execution/execution_step.py
@@ -176,28 +176,29 @@ def set_result(self, result: list[MaterializedResult[PartitionT]]) -> None:
     def done(self) -> bool:
         return self._result is not None
 
+    def result(self) -> MaterializedResult[PartitionT]:
+        assert self._result is not None, "Cannot call .result() on a PartitionTask that is not done"
+        return self._result
+
     def cancel(self) -> None:
         # Currently only implemented for Ray tasks.
-        if self._result is not None:
-            self._result.cancel()
+        if self.done():
+            self.result().cancel()
 
     def partition(self) -> PartitionT:
         """Get the PartitionT resulting from running this PartitionTask."""
-        assert self._result is not None
-        return self._result.partition()
+        return self.result().partition()
 
     def partition_metadata(self) -> PartitionMetadata:
         """Get the metadata of the result partition.
 
         (Avoids retrieving the actual partition itself if possible.)
         """
-        assert self._result is not None
-        return self._result.metadata()
+        return self.result().metadata()
 
     def vpartition(self) -> Table:
         """Get the raw vPartition of the result."""
-        assert self._result is not None
-        return self._result.vpartition()
+        return self.result().vpartition()
 
     def __str__(self) -> str:
         return super().__str__()
diff --git a/daft/execution/physical_plan.py b/daft/execution/physical_plan.py
index 8027ddf15e..a25f3511b4 100644
--- a/daft/execution/physical_plan.py
+++ b/daft/execution/physical_plan.py
@@ -741,7 +741,7 @@ def materialize(
         # Check if any inputs finished executing.
         while len(materializations) > 0 and materializations[0].done():
             done_task = materializations.popleft()
-            yield done_task._result
+            yield done_task.result()
 
         # Materialize a single dependency.
         try: