Snapshot strategies: newline for subquery (#6780)

* Snapshot strategies: newline for subquery

* add changie output

* add test for snapshot ending in comment

* remove import to be flake8 compliant

* add seed import

* add newlines for flake8 compliance

* typo fix

* Fixing up a test, adding a comment or two

* removed un-needed test fixtures

* removed even more un-needed fixtures, collapsed test to single class

* removed errant breakpoint()

* Fix a little typo

---------

Co-authored-by: Ian Knox <ian.knox@dbtlabs.com>
Co-authored-by: Mila Page <67295367+VersusFacit@users.noreply.github.com>

.changes/unreleased/Fixes-20230130-231456.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: 'Snapshot strategies: add a newline for subquery'
+time: 2023-01-30T23:14:56.131767823+01:00
+custom:
+  Author: RobbertDM
+  Issue: "6781"

core/dbt/include/global_project/macros/materializations/snapshots/strategies.sql

@@ -105,7 +105,11 @@
     {% elif check_cols_config is iterable and (check_cols_config | length) > 0 %}
         {#-- query for proper casing/quoting, to support comparison below --#}
         {%- set select_check_cols_from_target -%}
-          select {{ check_cols_config | join(', ') }} from ({{ node['compiled_code'] }}) subq
+            {#-- N.B. The whitespace below is necessary to avoid edge case issue with comments --#}
+            {#-- See: https://github.com/dbt-labs/dbt-core/issues/6781 --#}
+            select {{ check_cols_config | join(', ') }} from (
+                {{ node['compiled_code'] }}
+            ) subq
         {%- endset -%}
         {% set query_columns = get_columns_in_query(select_check_cols_from_target) %}
 

tests/functional/simple_snapshot/test_comment_ending_snapshot.py

@@ -0,0 +1,34 @@
+import pytest
+from dbt.tests.util import run_dbt
+import os
+
+snapshots_with_comment_at_end__snapshot_sql = """
+{% snapshot snapshot_actual %}
+    {{
+        config(
+            target_database=var('target_database', database),
+            target_schema=schema,
+            unique_key='id',
+            strategy='check',
+            check_cols=['email'],
+        )
+    }}
+    select * from {{target.database}}.{{schema}}.seed
+    -- Test comment to prevent recurrence of https://github.com/dbt-labs/dbt-core/issues/6781
+{% endsnapshot %}
+"""
+
+
+class TestSnapshotsWithCommentAtEnd:
+    @pytest.fixture(scope="class")
+    def snapshots(self):
+        return {"snapshot.sql": snapshots_with_comment_at_end__snapshot_sql}
+
+    def test_comment_ending(self, project):
+        path = os.path.join(project.test_data_dir, "seed_pg.sql")
+        project.run_sql_file(path)
+        # N.B. Snapshot is run twice to ensure snapshot_check_all_get_existing_columns is fully run
+        # (it exits early if the table doesn't already exist)
+        run_dbt(["snapshot"])
+        results = run_dbt(["snapshot"])
+        assert len(results) == 1