Use model alias for the CTE identifier generated during ephemeral materialization

.changes/unreleased/Fixes-20240610-195300.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Use model alias for the CTE identifier generated during ephemeral materialization
+time: 2024-06-10T19:53:00.086488231Z
+custom:
+    Author: jeancochrane
+    Issue: "5273"

dbt/adapters/base/relation.py

@@ -241,8 +241,11 @@ def create_ephemeral_from(
         relation_config: RelationConfig,
         limit: Optional[int] = None,
     ) -> Self:
-        # Note that ephemeral models are based on the name.
-        identifier = cls.add_ephemeral_prefix(relation_config.name)
+        # Note that ephemeral models are based on the identifier, which will
+        # point to the model's alias if one exists and otherwise fall back to
+        # the filename. This is intended to give the user more control over
+        # the way that the CTE name is constructed
+        identifier = cls.add_ephemeral_prefix(relation_config.identifier)
         return cls.create(
             type=cls.CTE,
             identifier=identifier,

tests/unit/test_relation.py

@@ -1,4 +1,4 @@
-from dataclasses import replace
+from dataclasses import dataclass, replace
 
 import pytest
 
@@ -79,3 +79,16 @@ def test_render_limited(limit, require_alias, expected_result):
     actual_result = my_relation.render_limited()
     assert actual_result == expected_result
     assert str(my_relation) == expected_result
+
+
+def test_create_ephemeral_from_uses_identifier():
+    @dataclass
+    class Node:
+        """Dummy implementation of RelationConfig protocol"""
+
+        name: str
+        identifier: str
+
+    node = Node(name="name_should_not_be_used", identifier="test")
+    ephemeral_relation = BaseRelation.create_ephemeral_from(node)
+    assert str(ephemeral_relation) == "__dbt__cte__test"