[BUG] Use models literal StructuredDataset to enable sd bypass task

flytekit/types/structured/structured_dataset.py

@@ -197,12 +197,25 @@ def return_sd() -> StructuredDataset:
             return df
 
         For details, please refer to this issue: https://github.com/flyteorg/flyte/issues/5954.
+
+        2. Need access to self._literal_sd when converting task output LiteralMap back to flyteidl, please see:
+        https://github.com/flyteorg/flytekit/blob/f938661ff8413219d1bea77f6914a58c302d5c6c/flytekit/bin/entrypoint.py#L326
+
+        For details, please refer to this issue: https://github.com/flyteorg/flyte/issues/5956.
         """
         to_literal = loop_manager.synced(flyte_dataset_transformer.async_to_literal)
         self._literal_sd = to_literal(ctx, self, StructuredDataset, expected).scalar.structured_dataset
         if self.metadata is None:
             self._metadata = self._literal_sd.metadata
 
+    def set_literal(self, ctx: FlyteContext, expected: LiteralType) -> None:
+        """
+        A public wrapper method to set the StructuredDataset Literal.
+
+        This method provides external access to the internal _set_literal method.
+        """
+        return self._set_literal(ctx, expected)
+
     def iter(self) -> Generator[DF, None, None]:
         if self._dataframe_type is None:
             raise ValueError("No dataframe type set. Use open() to set the local dataframe type you want to use.")
@@ -795,18 +808,18 @@ def dict_to_structured_dataset(
         if uri is None:
             raise ValueError("StructuredDataset's uri and file format should not be None")
 
+        # Instead of using python native StructuredDataset, we need to build a literals.StructuredDataset
+        # The reason is that _literal_sd of python sd is accessed when task output LiteralMap is converted back to flyteidl
+        # Hence, _literal_sd must have to_flyte_idl method
+        # See https://github.com/flyteorg/flytekit/blob/f938661ff8413219d1bea77f6914a58c302d5c6c/flytekit/bin/entrypoint.py#L326
+        # For details, please refer to this issue: https://github.com/flyteorg/flyte/issues/5956.
+        sdt = StructuredDatasetType(format=file_format)
+        metad = literals.StructuredDatasetMetadata(structured_dataset_type=sdt)
+        sd_literal = literals.StructuredDataset(uri=uri, metadata=metad)
+
         return StructuredDatasetTransformerEngine().to_python_value(
             FlyteContextManager.current_context(),
-            Literal(
-                scalar=Scalar(
-                    structured_dataset=StructuredDataset(
-                        metadata=StructuredDatasetMetadata(
-                            structured_dataset_type=StructuredDatasetType(format=file_format)
-                        ),
-                        uri=uri,
-                    )
-                )
-            ),
+            Literal(scalar=Scalar(structured_dataset=sd_literal)),
             expected_python_type,
         )