fix: warn on contract.enforced=true for materialized_view (#1421)

Resolves #1279

Upstream dbt does not support contracts on materialized views
([docs](https://docs.getdbt.com/docs/mesh/govern/model-contracts)).
dbt-databricks was silently accepting `contract.enforced: true`, hiding
yml/SQL drift. This PR emits a warning pointing at the dbt docs.
Strictly additive; no existing build outcome changes.

### Checklist

- [x] I have run this code in development and it appears to resolve the
stated issue
- [x] This PR includes tests, or tests are not required/relevant for
this PR
- [x] I have updated the `CHANGELOG.md`

Author: sd-db

CHANGELOG.md

@@ -11,6 +11,7 @@
 - Fix spurious `MicrobatchConcurrency` behavior-change warning firing on every run regardless of whether the project contained microbatch models ([#1406](https://github.com/databricks/dbt-databricks/issues/1406))
 - Stop emitting the `insert_overwrite will perform a dynamic insert overwrite` warning on every `insert_overwrite` run on SQL warehouses; warn instead only when `use_replace_on_for_insert_overwrite` is enabled but the cluster's DBR version does not support REPLACE ON ([#1305](https://github.com/databricks/dbt-databricks/issues/1305))
 - Fix DBR capability cache being permanently poisoned by a transient version-query failure ([#1398](https://github.com/databricks/dbt-databricks/issues/1398))
+- Warn when `contract.enforced: true` is set on a `materialized_view` model ([#1279](https://github.com/databricks/dbt-databricks/issues/1279))
 
 ## dbt-databricks 1.11.7 (Apr 17, 2026)
 

dbt/include/databricks/macros/relations/materialized_view/create.sql

@@ -24,6 +24,9 @@
   {%- set model_columns = model.get('columns', {}) -%}
   {%- set contract_config = config.get('contract') -%}
   {%- if contract_config and contract_config.enforced -%}
+    {%- do exceptions.warn(
+         "contract.enforced=true on materialized_view '" ~ model.name ~ "': not supported by dbt (https://docs.getdbt.com/docs/mesh/govern/model-contracts). dbt-databricks provides best-effort support that may change without notice."
+       ) -%}
     {%- set model_constraints = model.get('constraints', []) -%}
   {%- else -%}
     {%- set model_constraints = [] -%}