feat: local PostgreSQL container for query analysis / validation

[nikolayk812]

What do you want to change?

sqlc query analysis requires a live PostgreSQL instance, but setting one up means either running a database separately. It also requires schema migration steps outside of sqlc.

Proposed change:

Add a testcontainers_image field to the database config block. When set, sqlc automatically starts a local PostgreSQL Docker container, applies schema migrations, and uses it for analysis — then tears it down when done.

  database:
    testcontainers_image: "postgres:18-alpine"

Mutually exclusive with uri and managed.

Pros:

• Real PostgreSQL analysis without any external DB setup
• Single config field replaces: start DB → apply migrations → pass URI

Scope:

• New testcontainers_image config field (v1 + v2 schemas)
• Validation: mutual exclusion with uri and managed
• PostgreSQL only (initial support)
• Container lifecycle managed by sqlc (start on first query, teardown on close)

What database engines need to be changed?

PostgreSQL

What programming language backends need to be changed?

Go