Ensure that target_schema from snapshot config is promoted to node level

.changes/unreleased/Fixes-20230717-160652.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Copy target_schema from config into snapshot node
+time: 2023-07-17T16:06:52.957724-04:00
+custom:
+  Author: gshank
+  Issue: "6745"

core/dbt/contracts/graph/model_config.py

@@ -619,6 +619,8 @@ class SnapshotConfig(EmptySnapshotConfig):
     @classmethod
     def validate(cls, data):
         super().validate(data)
+        # Note: currently you can't just set these keys in schema.yml because this validation
+        # will fail when parsing the snapshot node.
         if not data.get("strategy") or not data.get("unique_key") or not data.get("target_schema"):
             raise ValidationError(
                 "Snapshots must be configured with a 'strategy', 'unique_key', "
@@ -649,6 +651,7 @@ def validate(cls, data):
         if data.get("materialized") and data.get("materialized") != "snapshot":
             raise ValidationError("A snapshot must have a materialized value of 'snapshot'")
 
+    # Called by "calculate_node_config_dict" in ContextConfigGenerator
     def finalize_and_validate(self):
         data = self.to_dict(omit_none=True)
         self.validate(data)

core/dbt/parser/base.py

@@ -102,8 +102,7 @@ def __init__(self, config: RuntimeConfig, manifest: Manifest, component: str) ->
         self.package_updaters = package_updaters
         self.component = component
 
-    def __call__(self, parsed_node: Any, config_dict: Dict[str, Any]) -> None:
-        override = config_dict.get(self.component)
+    def __call__(self, parsed_node: Any, override: Optional[str]) -> None:
         if parsed_node.package_name in self.package_updaters:
             new_value = self.package_updaters[parsed_node.package_name](override, parsed_node)
         else:
@@ -280,9 +279,19 @@ def update_parsed_node_config_dict(
     def update_parsed_node_relation_names(
         self, parsed_node: IntermediateNode, config_dict: Dict[str, Any]
     ) -> None:
-        self._update_node_database(parsed_node, config_dict)
-        self._update_node_schema(parsed_node, config_dict)
-        self._update_node_alias(parsed_node, config_dict)
+
+        # These call the RelationUpdate callable to go through generate_name macros
+        self._update_node_database(parsed_node, config_dict.get("database"))
+        self._update_node_schema(parsed_node, config_dict.get("schema"))
+        self._update_node_alias(parsed_node, config_dict.get("alias"))
+
+        # Snapshot nodes use special "target_database" and "target_schema" fields for some reason
+        if parsed_node.resource_type == NodeType.Snapshot:
+            if "target_database" in config_dict and config_dict["target_database"]:
+                parsed_node.database = config_dict["target_database"]
+            if "target_schema" in config_dict and config_dict["target_schema"]:
+                parsed_node.schema = config_dict["target_schema"]
+
         self._update_node_relation_name(parsed_node)
 
     def update_parsed_node_config(
@@ -349,7 +358,7 @@ def update_parsed_node_config(
         # do this once before we parse the node database/schema/alias, so
         # parsed_node.config is what it would be if they did nothing
         self.update_parsed_node_config_dict(parsed_node, config_dict)
-        # This updates the node database/schema/alias
+        # This updates the node database/schema/alias/relation_name
         self.update_parsed_node_relation_names(parsed_node, config_dict)
 
         # tests don't have hooks

tests/functional/simple_snapshot/fixtures.py

@@ -96,6 +96,18 @@
         owner: 'a_owner'
 """
 
+models__schema_with_target_schema_yml = """
+version: 2
+snapshots:
+  - name: snapshot_actual
+    tests:
+      - mutually_exclusive_ranges
+    config:
+      meta:
+        owner: 'a_owner'
+      target_schema: schema_from_schema_yml
+"""
+
 models__ref_snapshot_sql = """
 select * from {{ ref('snapshot_actual') }}
 """
@@ -281,6 +293,26 @@
 {% endsnapshot %}
 """
 
+snapshots_pg__snapshot_no_target_schema_sql = """
+{% snapshot snapshot_actual %}
+
+    {{
+        config(
+            target_database=var('target_database', database),
+            unique_key='id || ' ~ "'-'" ~ ' || first_name',
+            strategy='timestamp',
+            updated_at='updated_at',
+        )
+    }}
+
+    {% if var('invalidate_hard_deletes', 'false') | as_bool %}
+        {{ config(invalidate_hard_deletes=True) }}
+    {% endif %}
+
+    select * from {{target.database}}.{{target.schema}}.seed
+
+{% endsnapshot %}
+"""
 
 models_slow__gen_sql = """
 

tests/functional/simple_snapshot/test_basic_snapshot.py

@@ -2,13 +2,15 @@
 from datetime import datetime
 import pytz
 import pytest
-from dbt.tests.util import run_dbt, check_relations_equal, relation_from_name
+from dbt.tests.util import run_dbt, check_relations_equal, relation_from_name, write_file
 from tests.functional.simple_snapshot.fixtures import (
     models__schema_yml,
+    models__schema_with_target_schema_yml,
     models__ref_snapshot_sql,
     seeds__seed_newcol_csv,
     seeds__seed_csv,
     snapshots_pg__snapshot_sql,
+    snapshots_pg__snapshot_no_target_schema_sql,
     macros__test_no_overlaps_sql,
     macros_custom_snapshot__custom_sql,
     snapshots_pg_custom_namespaced__snapshot_sql,
@@ -123,6 +125,41 @@ def test_basic_ref(self, project):
         ref_setup(project, num_snapshot_models=1)
 
 
+class TestBasicTargetSchemaConfig(Basic):
+    @pytest.fixture(scope="class")
+    def snapshots(self):
+        return {"snapshot.sql": snapshots_pg__snapshot_no_target_schema_sql}
+
+    @pytest.fixture(scope="class")
+    def project_config_update(self, unique_schema):
+        return {
+            "snapshots": {
+                "test": {
+                    "target_schema": unique_schema + "_alt",
+                }
+            }
+        }
+
+    def test_target_schema(self, project):
+        manifest = run_dbt(["parse"])
+        assert len(manifest.nodes) == 5
+        # ensure that the schema in the snapshot node is the same as target_schema
+        snapshot_id = "snapshot.test.snapshot_actual"
+        snapshot_node = manifest.nodes[snapshot_id]
+        assert snapshot_node.schema == f"{project.test_schema}_alt"
+        assert (
+            snapshot_node.relation_name
+            == f'"{project.database}"."{project.test_schema}_alt"."snapshot_actual"'
+        )
+        assert snapshot_node.meta == {"owner": "a_owner"}
+
+        # write out schema.yml file and check again
+        write_file(models__schema_with_target_schema_yml, "models", "schema.yml")
+        manifest = run_dbt(["parse"])
+        snapshot_node = manifest.nodes[snapshot_id]
+        assert snapshot_node.schema == "schema_from_schema_yml"
+
+
 class CustomNamespace:
     @pytest.fixture(scope="class")
     def snapshots(self):