fix(IncrementingCountCursor): Raise a better error when users attempt to use IncrementingCountCursor with partition router (#784)

Author: brianjlai

airbyte_cdk/sources/declarative/parsers/model_to_component_factory.py

@@ -2208,6 +2208,14 @@ def _build_concurrent_cursor(
             and stream_slicer
             and not isinstance(stream_slicer, SinglePartitionRouter)
         ):
+            if isinstance(model.incremental_sync, IncrementingCountCursorModel):
+                # We don't currently support usage of partition routing and IncrementingCountCursor at the
+                # same time because we didn't solve for design questions like what the lookback window would
+                # be as well as global cursor fall backs. We have not seen customers that have needed both
+                # at the same time yet and are currently punting on this until we need to solve it.
+                raise ValueError(
+                    f"The low-code framework does not currently support usage of a PartitionRouter and an IncrementingCountCursor at the same time. Please specify only one of these options for stream {stream_name}."
+                )
             return self.create_concurrent_cursor_from_perpartition_cursor(  # type: ignore # This is a known issue that we are creating and returning a ConcurrentCursor which does not technically implement the (low-code) StreamSlicer. However, (low-code) StreamSlicer and ConcurrentCursor both implement StreamSlicer.stream_slices() which is the primary method needed for checkpointing
                 state_manager=self._connector_state_manager,
                 model_type=DatetimeBasedCursorModel,

unit_tests/sources/declarative/parsers/test_model_to_component_factory.py

@@ -3669,6 +3669,58 @@ def test_create_concurrent_cursor_from_perpartition_cursor_runs_state_migrations
     )
 
 
+def test_incrementing_count_cursor_with_partition_router_raises_error():
+    content = """
+    type: DeclarativeStream
+    primary_key: "id"
+    name: test
+    schema_loader:
+      type: InlineSchemaLoader
+      schema:
+        $schema: "http://json-schema.org/draft-07/schema"
+        type: object
+        properties:
+          id:
+            type: string
+    incremental_sync:
+      type: "IncrementingCountCursor"
+      cursor_field: "mid"
+      start_value: "0"
+    retriever:
+      type: SimpleRetriever
+      name: test
+      requester:
+        type: HttpRequester
+        name: "test"
+        url_base: "https://api.test.com/v3/"
+        http_method: "GET"
+        authenticator:
+          type: NoAuth
+      record_selector:
+        type: RecordSelector
+        extractor:
+          type: DpathExtractor
+          field_path: []
+      partition_router:
+        type: ListPartitionRouter
+        cursor_field: arbitrary
+        values:
+          - item_1
+          - item_2
+      """
+
+    factory = ModelToComponentFactory(
+        emit_connector_builder_messages=True, connector_state_manager=ConnectorStateManager()
+    )
+
+    with pytest.raises(ValueError):
+        factory.create_component(
+            model_type=DeclarativeStreamModel,
+            component_definition=YamlDeclarativeSource._parse(content),
+            config=input_config,
+        )
+
+
 def test_create_concurrent_cursor_uses_min_max_datetime_format_if_defined():
     """
     Validates a special case for when the start_time.datetime_format and end_time.datetime_format are defined, the date to