`CAST` to `timestamp` works in Postgres but breaks in Cube when the timestamp has a UTC offset without minutes

[rolodato]

Describe the bug

The following query breaks in Cube's Postgres SQL API, but works in regular Postgres:

SELECT CAST('2026-01-26 00:00:00+00' AS timestamp)

returns:

[XX000] ERROR: Post-processing Error: Cast error: Error parsing '2026-01-26 00:00:00+00' as timestamp

This only happens when the UTC offset in the timestamp only has hours and not minutes. For example, these do work in both Cube and Postgres:

SELECT CAST('2026-01-26 00:00:00+0000' AS timestamp)
SELECT CAST('2026-01-26 00:00:00+00:00' AS timestamp)

This is possibly happening because Cube interprets this timestamp as RFC 3339, which does require 4 digits for the UTC offset: https://datatracker.ietf.org/doc/html/rfc3339#section-5.6

In contrast, Postgres uses ISO 8601 and other formats which do admit a UTC offset having only hours.

To Reproduce

1. Run Cube with the Postgres-compatible API, using e.g. a Docker Compose file like so:

services:
  cube_api:
    restart: always
    image: cubejs/cube:latest
    environment:
      - CUBEJS_DB_TYPE=postgres
      - CUBEJS_API_SECRET=secret
      - CUBEJS_PG_SQL_PORT=15432
      - CUBEJS_SQL_USER=cube
      - CUBEJS_SQL_PASSWORD=secret

2. Connect to Cube using any Postgres client
3. Run this query: SELECT CAST('2026-01-26 00:00:00+00' AS timestamp)

Expected behavior

Return the same result as regular Postgres: 2026-01-26 00:00:00.000000

Screenshots

N/A

Minimally reproducible Cube Schema

N/A

Version:

Tested on Cube API version 1.6.3.

Additional context

Metabase generates queries in this format when connecting to Cube as a Postgres data source. This can break queries created using the GUI query builder. The only workaround is to rewrite the query using SQL.