Version 0 for model works for latest_version (#7712) (#7780)

(cherry picked from commit 79bd985)

Co-authored-by: Gerda Shank <gerda@dbtlabs.com>

.changes/unreleased/Fixes-20230526-164727.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Using version 0 works when resolving single model
+time: 2023-05-26T16:47:27.6065-04:00
+custom:
+  Author: gshank
+  Issue: "7372"

core/dbt/contracts/graph/manifest.py

@@ -183,7 +183,7 @@ def find(
                         if v.name == node.name and v.version is not None
                     ]
                 )
-                assert node.latest_version  # for mypy, whenever i may find it
+                assert node.latest_version is not None  # for mypy, whenever i may find it
                 if max_version > UnparsedVersion(node.latest_version):
                     fire_event(
                         UnpinnedRefNewVersionAvailable(

tests/functional/graph_selection/test_version_selection.py

@@ -109,3 +109,25 @@ def test_select_group_and_children_selector_str(self, project):  # noqa
     def test_select_models_two_versions(self, project):
         results = run_dbt(["ls", "--models", "version:latest version:old"])
         assert sorted(results) == ["test.versioned.v1", "test.versioned.v2"]
+
+
+my_model_yml = """
+models:
+  - name: my_model
+    versions:
+      - v: 0
+"""
+
+
+class TestVersionZero:
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {
+            "my_model.sql": "select 1 as id",
+            "another.sql": "select * from {{ ref('my_model') }}",
+            "schema.yml": my_model_yml,
+        }
+
+    def test_version_zero(self, project):
+        results = run_dbt(["run"])
+        assert len(results) == 2