`columns` introspection reports a domain column's **base type**, discarding the domain identity

[coderdan]

Bug report

For a column whose type is a DOMAIN, the columns query resolves the column to the domain's base type and never surfaces the domain itself. Both output fields that could carry the type name — format and data_type — collapse to the base type, so downstream consumers (notably the Studio table editor grid) label the column with the base type (text, jsonb, …) instead of the domain name.

Example from CipherStash Encrypt Query Language (EQL):

CREATE DOMAIN public.eql_v3_text_search AS jsonb
    CHECK (
        jsonb_typeof(VALUE) = 'object'
        AND VALUE ? 'v'
        AND VALUE ? 'i'
        AND VALUE ? 'c'
        AND VALUE->>'v' = '3'
    );

Creating a table with this type works but the API reports the type as jsonb instead of the domain.

Schema visualizer shows the type as jsonb:

The meta API response:

curl -s "http://127.0.0.1:54321/pg/tables?included_schemas=public" | jq

{
     // ...
     {
        "table_id": 23315,
        "schema": "public",
        "table": "users",
        "id": "23315.3",
        "ordinal_position": 3,
        "name": "name",
        "default_value": "NULL::jsonb",
        "data_type": "jsonb",
        "format": "jsonb",
        "is_identity": false,
        "identity_generation": null,
        "is_generated": false,
        "is_nullable": true,
        "is_updatable": true,
        "is_unique": false,
        "enums": [],
        "check": null,
        "comment": null
    }
}
// ...

psql shows the correct domain type name:

psql \d shows the domain name for the same column, because it uses format_type(atttypid) (domain-aware). The Studio "New column" type picker also shows the domain name, because it comes from the types query (format_type(t.oid)). Only the columns path flattens it — so the same type is displayed inconsistently across the UI.

Environment

• postgres-meta v0.96.1 (bundled with Supabase CLI 2.84.2); also present on master @ f21a4da.

• PostgreSQL 15 (Supabase local dev stack) and Supabase hosted.

• I confirm this is a bug with Supabase, not with my own application.

• I confirm I have searched the Docs, GitHub Discussions, and Discord.

[coderdan]

In src/lib/sql/columns.sql.ts:

format (line ~39) prefers the domain's base type name:

COALESCE(bt.typname, t.typname) AS format,

bt is joined only for domains (t.typtype = 'd' AND t.typbasetype = bt.oid), so for a domain bt.typname is the base type and wins over the domain's own t.typname.

data_type (the CASE ending ~line 38) does the same via format_type(t.typbasetype, …) for a domain whose base type is in pg_catalog:

WHEN t.typtype = 'd' THEN CASE
  ...
  WHEN nbt.nspname = 'pg_catalog' THEN format_type(t.typbasetype, NULL)  -- base type
  ELSE 'USER-DEFINED'
END

So neither field ever carries the domain name; the domain identity is lost.