Fix #8160: Warn when --state == --target

.changes/unreleased/Fixes-20230912-225329.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Warn when --state == --target
+time: 2023-09-12T22:53:29.869746+01:00
+custom:
+  Author: aranke
+  Issue: "8160"

core/dbt/contracts/state.py

@@ -1,8 +1,11 @@
 from pathlib import Path
-from .graph.manifest import WritableManifest
-from .results import RunResultsArtifact
-from .results import FreshnessExecutionResultArtifact
 from typing import Optional
+
+from dbt.contracts.graph.manifest import WritableManifest
+from dbt.contracts.results import FreshnessExecutionResultArtifact
+from dbt.contracts.results import RunResultsArtifact
+from dbt.events.functions import fire_event
+from dbt.events.types import WarnStateTargetEqual
 from dbt.exceptions import IncompatibleSchemaError
 
 
@@ -16,6 +19,9 @@ def __init__(self, state_path: Path, target_path: Path, project_root: Path):
         self.sources: Optional[FreshnessExecutionResultArtifact] = None
         self.sources_current: Optional[FreshnessExecutionResultArtifact] = None
 
+        if self.state_path == self.target_path:
+            fire_event(WarnStateTargetEqual(state_path=str(self.state_path)))
+
         # Note: if state_path is absolute, project_root will be ignored.
         manifest_path = self.project_root / self.state_path / "manifest.json"
         if manifest_path.exists() and manifest_path.is_file():

core/dbt/events/types.proto

@@ -1287,6 +1287,15 @@ message UnversionedBreakingChangeMsg {
     UnversionedBreakingChange data = 2;
 }
 
+// I072
+message WarnStateTargetEqual {
+    string state_path = 1;
+}
+
+message WarnStateTargetEqualMsg {
+    EventInfo info = 1;
+    WarnStateTargetEqual data = 2;
+}
 
 // M - Deps generation
 

core/dbt/events/types.py

@@ -1,6 +1,5 @@
 import json
 
-from dbt.ui import line_wrap_message, warning_tag, red, green, yellow
 from dbt.constants import MAXIMUM_SEED_SIZE_NAME, PIN_PACKAGE_URL
 from dbt.events.base_types import (
     DynamicLevel,
@@ -11,8 +10,8 @@
     EventLevel,
 )
 from dbt.events.format import format_fancy_output_line, pluralize, timestamp_to_datetime_string
-
 from dbt.node_types import NodeType
+from dbt.ui import line_wrap_message, warning_tag, red, green, yellow
 
 
 # The classes in this file represent the data necessary to describe a
@@ -1247,6 +1246,16 @@ def message(self) -> str:
         )
 
 
+class WarnStateTargetEqual(WarnLevel):
+    def code(self):
+        return "I072"
+
+    def message(self) -> str:
+        return yellow(
+            f"Warning: The state and target directories are the same: '{self.state_path}'"
+        )
+
+
 # =======================================================
 # M - Deps generation
 # =======================================================

core/dbt/include/global_project/macros/materializations/models/clone/clone.sql

@@ -33,7 +33,12 @@
 
       -- as a general rule, data platforms that can clone tables can also do atomic 'create or replace'
       {% call statement('main') %}
-          {{ create_or_replace_clone(target_relation, defer_relation) }}
+          {% if target_relation and defer_relation and target_relation == defer_relation %}
+              {{ log("Target relation and defer relation are the same, skipping clone for relation: " ~ target_relation) }}
+          {% else %}
+              {{ create_or_replace_clone(target_relation, defer_relation) }}
+          {% endif %
+
       {% endcall %}
 
       {% set should_revoke = should_revoke(existing_relation, full_refresh_mode=True) %}

tests/adapter/dbt/tests/adapter/dbt_clone/test_dbt_clone.py

@@ -1,10 +1,11 @@
-import pytest
 import os
 import shutil
-from copy import deepcopy
 from collections import Counter
+from copy import deepcopy
+
+import pytest
+
 from dbt.exceptions import DbtRuntimeError
-from dbt.tests.util import run_dbt
 from dbt.tests.adapter.dbt_clone.fixtures import (
     seed_csv,
     table_model_sql,
@@ -18,6 +19,7 @@
     infinite_macros_sql,
     custom_can_clone_tables_false_macros_sql,
 )
+from dbt.tests.util import run_dbt, run_dbt_and_capture
 
 
 class BaseClone:
@@ -215,3 +217,18 @@ def clean_up(self, project):
             project.adapter.drop_schema(relation)
 
     pass
+
+
+class TestCloneSameTargetAndState(BaseClone):
+    def test_clone_same_target_and_state(self, project, unique_schema, other_schema):
+        project.create_test_schema(other_schema)
+        self.run_and_save_state(project.project_root)
+
+        clone_args = [
+            "clone",
+            "--state",
+            "target",
+        ]
+
+        results, output = run_dbt_and_capture(clone_args, expect_pass=False)
+        assert "Warning: The state and target directories are the same: 'target'" in output