feat(rest): support storage-credentials in PlanCompleted response (partial fix for #3165)

Adds storage-credentials support for CompletedPlanningResult (PlanCompleted).
LoadCredentialsResponse support is pending.

Author: tanmayrauth

pyiceberg/catalog/rest/__init__.py

@@ -528,6 +528,29 @@ def plan_scan(self, identifier: str | Identifier, request: PlanTableScanRequest)
         Returns:
             List of FileScanTask objects ready for execution.
 
+        Raises:
+            RuntimeError: If planning fails, is cancelled, or returns unexpected response.
+            NotImplementedError: If async planning is required but not yet supported.
+        """
+        tasks, _ = self._plan_scan_for_table(identifier, request)
+        return tasks
+
+    def _plan_scan_for_table(
+        self, identifier: str | Identifier, request: PlanTableScanRequest, table_location: str | None = None
+    ) -> tuple[list[FileScanTask], Properties]:
+        """Plan a table scan and return FileScanTasks along with resolved storage credentials.
+
+        Per Iceberg spec: storage-credentials in the PlanCompleted response take precedence over
+        catalog config and should be applied to the FileIO used to read data files.
+
+        Args:
+            identifier: Table identifier.
+            request: The scan plan request parameters.
+            table_location: The table's metadata location, used for credential prefix matching.
+
+        Returns:
+            Tuple of (list of FileScanTask objects, resolved credential Properties).
+
         Raises:
             RuntimeError: If planning fails, is cancelled, or returns unexpected response.
             NotImplementedError: If async planning is required but not yet supported.
@@ -548,6 +571,8 @@ def plan_scan(self, identifier: str | Identifier, request: PlanTableScanRequest)
         if not isinstance(response, PlanCompleted):
             raise RuntimeError(f"Invalid planStatus for response: {type(response).__name__}")
 
+        credential_config = self._resolve_storage_credentials(response.storage_credentials or [], table_location)
+
         tasks: list[FileScanTask] = []
 
         # Collect tasks from initial response
@@ -563,7 +588,7 @@ def plan_scan(self, identifier: str | Identifier, request: PlanTableScanRequest)
                 tasks.append(FileScanTask.from_rest_response(task, batch.delete_files))
             pending_tasks.extend(batch.plan_tasks)
 
-        return tasks
+        return tasks, credential_config
 
     def _create_legacy_oauth2_auth_manager(self, session: Session) -> AuthManager:
         """Create the LegacyOAuth2AuthManager by fetching required properties.

pyiceberg/table/__init__.py

@@ -2054,7 +2054,16 @@ def _plan_files_server_side(self) -> Iterable[FileScanTask]:
             case_sensitive=self.case_sensitive,
         )
 
-        return self.catalog.plan_scan(self.table_identifier, request)
+        tasks, credential_config = self.catalog._plan_scan_for_table(
+            self.table_identifier, request, self.table_metadata.location
+        )
+        # Per Iceberg spec: storage-credentials from PlanCompleted take precedence over config.
+        # Update the FileIO so data files in this scan are read with the vended credentials.
+        if credential_config:
+            self.io = self.catalog._load_file_io(
+                {**self.io.properties, **credential_config}, self.table_metadata.location
+            )
+        return tasks
 
     def _plan_files_local(self) -> Iterable[FileScanTask]:
         """Plan files locally by reading manifests."""
@@ -2112,9 +2121,13 @@ def to_arrow(self) -> pa.Table:
         """
         from pyiceberg.io.pyarrow import ArrowScan
 
+        # plan_files() must be called before capturing self.io so that any vended credentials
+        # returned by server-side scan planning (PlanCompleted.storage_credentials) are applied
+        # to self.io before ArrowScan is constructed.
+        tasks = self.plan_files()
         return ArrowScan(
             self.table_metadata, self.io, self.projection(), self.row_filter, self.case_sensitive, self.limit
-        ).to_table(self.plan_files())
+        ).to_table(tasks)
 
     def to_arrow_batch_reader(self) -> pa.RecordBatchReader:
         """Return an Arrow RecordBatchReader from this DataScan.
@@ -2132,9 +2145,11 @@ def to_arrow_batch_reader(self) -> pa.RecordBatchReader:
         from pyiceberg.io.pyarrow import ArrowScan, schema_to_pyarrow
 
         target_schema = schema_to_pyarrow(self.projection())
+        # plan_files() must be called before capturing self.io (same reason as to_arrow).
+        tasks = self.plan_files()
         batches = ArrowScan(
             self.table_metadata, self.io, self.projection(), self.row_filter, self.case_sensitive, self.limit
-        ).to_record_batches(self.plan_files())
+        ).to_record_batches(tasks)
 
         return pa.RecordBatchReader.from_batches(
             target_schema,

tests/catalog/test_rest.py

@@ -2621,3 +2621,95 @@ def test_load_table_without_storage_credentials(
     )
     assert actual.metadata.model_dump() == expected.metadata.model_dump()
     assert actual == expected
+
+
+
+
+def test_plan_scan_with_storage_credentials(
+    rest_mock: Mocker, example_table_metadata_with_snapshot_v1: dict[str, Any]
+) -> None:
+    metadata_location = "s3://warehouse/database/table/metadata/00001.metadata.json"
+    rest_mock.get(
+        f"{TEST_URI}v1/namespaces/fokko/tables/table",
+        json={
+            "metadata-location": metadata_location,
+            "metadata": example_table_metadata_with_snapshot_v1,
+            "config": {},
+        },
+        status_code=200,
+        request_headers=TEST_HEADERS,
+    )
+    rest_mock.post(
+        f"{TEST_URI}v1/namespaces/fokko/tables/table/plan",
+        json={
+            "status": "completed",
+            "file-scan-tasks": [],
+            "delete-files": [],
+            "plan-tasks": [],
+            "storage-credentials": [
+                {
+                    "prefix": "s3://warehouse/database/table",
+                    "config": {
+                        "s3.access-key-id": "plan-vended-key",
+                        "s3.secret-access-key": "plan-vended-secret",
+                        "s3.session-token": "plan-vended-token",
+                    },
+                }
+            ],
+        },
+        status_code=200,
+        request_headers=TEST_HEADERS,
+    )
+    from pyiceberg.catalog.rest.scan_planning import PlanTableScanRequest
+
+    catalog = RestCatalog("rest", uri=TEST_URI, token=TEST_TOKEN, **{"rest-scan-planning-enabled": "true"})
+    tasks, credential_config = catalog._plan_scan_for_table(
+        ("fokko", "table"),
+        PlanTableScanRequest(),
+        table_location="s3://warehouse/database/table",
+    )
+
+    assert tasks == []
+    assert credential_config == {
+        "s3.access-key-id": "plan-vended-key",
+        "s3.secret-access-key": "plan-vended-secret",
+        "s3.session-token": "plan-vended-token",
+    }
+
+
+def test_plan_scan_without_storage_credentials(
+    rest_mock: Mocker, example_table_metadata_with_snapshot_v1: dict[str, Any]
+) -> None:
+    metadata_location = "s3://warehouse/database/table/metadata/00001.metadata.json"
+    rest_mock.get(
+        f"{TEST_URI}v1/namespaces/fokko/tables/table",
+        json={
+            "metadata-location": metadata_location,
+            "metadata": example_table_metadata_with_snapshot_v1,
+            "config": {},
+        },
+        status_code=200,
+        request_headers=TEST_HEADERS,
+    )
+    rest_mock.post(
+        f"{TEST_URI}v1/namespaces/fokko/tables/table/plan",
+        json={
+            "status": "completed",
+            "file-scan-tasks": [],
+            "delete-files": [],
+            "plan-tasks": [],
+        },
+        status_code=200,
+        request_headers=TEST_HEADERS,
+    )
+    from pyiceberg.catalog.rest.scan_planning import PlanTableScanRequest
+
+    catalog = RestCatalog("rest", uri=TEST_URI, token=TEST_TOKEN, **{"rest-scan-planning-enabled": "true"})
+    tasks, credential_config = catalog._plan_scan_for_table(
+        ("fokko", "table"),
+        PlanTableScanRequest(),
+        table_location="s3://warehouse/database/table",
+    )
+
+    assert tasks == []
+    assert credential_config == {}