Users should always call `adapter.drop_relation` instead of calling `{{ drop_relation() }}` directly

[jtcohen6]

Adapter maintainers and users should always call either:

• adapter.drop_relation
• drop_relation_if_exists (syntactic sugar that checks cache first, and then calls adapter.drop_relation)

Why? Calling {{ drop_relation() }} directly does not update the cache!! That happens within the adapter drop_relation method here:

https://github.com/dbt-labs/dbt-adapters/blob/a2292c8ec76e4c9f03869ad95817a2ad82dfb34b/dbt/adapters/sql/impl.py#L140-L145

Even though this method ultimately shells out to a macro called {{ drop_relation() }}:

https://github.com/dbt-labs/dbt-adapters/blob/a2292c8ec76e4c9f03869ad95817a2ad82dfb34b/dbt/include/global_project/macros/relations/drop.sql#L26-L34

Proposals

• Document this for adapter maintainers and users (https://docs.getdbt.com/reference/dbt-jinja-functions/adapter#drop_relation)
• Deprecate/remove/rename {{ drop_relation() }}, either by calling dispatch directly in the adapter method or renaming this macro so that it is more clearly returning adapter.dispatch(DROP_RELATION_MACRO_NAME) and not a macro that should be called directly