Custom dbt adapter inheriting from the Postgres adapter

Hi there,

I’m currently working on trying to extend the default Postgres adapter, and trying to just create a child adapter that acts as a pass through class without changing the parent’s functionality doesn’t seem to be working as expected.

I started by using the adapter creation script and the Redshift adapter code as a basis for this new adapter. In the Redshift macros, the Postgres versions of the macros are called explicitly. One example being the create_schema macro from adapters.sql

{% macro redshift__create_schema(relation) -%}
  {{ postgres__create_schema(relation) }}
{% endmacro %}

If I include this in my new adapter named custompostgres, but change redshift to custompostgres, running the dbt adapter test suite fails with the exception:

“Compilation Error in macro custompostgres__create_schema (macros/adapter.sql)
‘postgres__create_schema’ is undefined”

This happens for all tests since most are referencing similarly defined macros somewhere. Running the same test spec file with the default postgres adapter completely passes. I don’t have a redshift cluster to test against, so I don’t know if the redshift adapter passes it.

The custom file also mimics the Redshift adapter by requiring both dbt and dbt-postgres as well as setting packages=find_namespace_packages(include=['dbt', 'dbt.*']),

Any idea on how I can reference the inherited class’s macros, or what I’m likely doing wrong here? Let me know if there are any other details that would help.