Handle unknown type_code for model contracts (#8887)

* Handle unknown `type_code` for model contracts

* Changelog entry

* Fix changelog entry

* Functional test for a `type_code` that is not recognized by psycopg2

* Functional tests for data type mismatches

.changes/unreleased/Fixes-20231024-110151.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Handle unknown `type_code` for model contracts
+time: 2023-10-24T11:01:51.980781-06:00
+custom:
+  Author: dbeatty10
+  Issue: 8877 8353

plugins/postgres/dbt/adapters/postgres/connections.py

@@ -204,4 +204,7 @@ def get_response(cls, cursor) -> AdapterResponse:
 
     @classmethod
     def data_type_code_to_name(cls, type_code: int) -> str:
-        return string_types[type_code].name
+        if type_code in string_types:
+            return string_types[type_code].name
+        else:
+            return f"unknown type_code {type_code}"

tests/functional/contracts/test_nonstandard_data_type.py

@@ -0,0 +1,76 @@
+import pytest
+from dbt.tests.util import run_dbt, run_dbt_and_capture
+
+
+my_numeric_model_sql = """
+select
+  12.34 as price
+"""
+
+my_money_model_sql = """
+select
+  cast('12.34' as money) as price
+"""
+
+model_schema_money_yml = """
+models:
+  - name: my_model
+    config:
+      contract:
+        enforced: true
+    columns:
+      - name: price
+        data_type: money
+"""
+
+model_schema_numeric_yml = """
+models:
+  - name: my_model
+    config:
+      contract:
+        enforced: true
+    columns:
+      - name: price
+        data_type: numeric
+"""
+
+
+class TestModelContractUnrecognizedTypeCode1:
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {
+            "my_model.sql": my_money_model_sql,
+            "schema.yml": model_schema_money_yml,
+        }
+
+    def test_nonstandard_data_type(self, project):
+        run_dbt(["run"], expect_pass=True)
+
+
+class TestModelContractUnrecognizedTypeCodeActualMismatch:
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {
+            "my_model.sql": my_money_model_sql,
+            "schema.yml": model_schema_numeric_yml,
+        }
+
+    def test_nonstandard_data_type(self, project):
+        expected_msg = "unknown type_code 790 | DECIMAL       | data type mismatch"
+        _, logs = run_dbt_and_capture(["run"], expect_pass=False)
+        assert expected_msg in logs
+
+
+class TestModelContractUnrecognizedTypeCodeExpectedMismatch:
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {
+            "my_model.sql": my_numeric_model_sql,
+            "schema.yml": model_schema_money_yml,
+        }
+
+    def test_nonstandard_data_type(self, project):
+        expected_msg = "DECIMAL         | unknown type_code 790 | data type mismatch"
+        _, logs = run_dbt_and_capture(["run"], expect_pass=False)
+        print(logs)
+        assert expected_msg in logs