> ## Documentation Index
> Fetch the complete documentation index at: https://supaschema.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Corpus oracle

> Run dirty-real catalog regression tests for cross-lane schema diff correctness.

Use this when you need regression coverage for false drift and catalog parity bugs.

The corpus lane applies deliberately messy migrations to a disposable database, reconciles that database against a clean declarative tree, checks the rendered migration, applies it twice, and requires the final diff to converge to zero operations.

## Use this when

* A bug involved false drift or catalog mismatch.
* Unit fixtures were too clean to catch the failure.
* You want package-level proof across real PostgreSQL catalog noise.
* A consuming repo needs its own incident-history corpus.

## Do this

Run the bundled corpus:

```bash theme={null}
npm run corpus:check
```

Or run the CLI directly:

```bash theme={null}
npx supaschema corpus --corpus-dir corpus/supabase-style --database-url "$DATABASE_URL"
```

Without a resolvable database URL, the command prints a skip notice and exits 0.

## Add a case

For every false-drift or parity bug, add the triggering shape in the same change:

* put the dirty migration in `corpus/supabase-style/migrations/`;
* put the clean end state in `corpus/supabase-style/tree/`;
* keep expected settings in `corpus/supabase-style/corpus.json`;
* prove `npm run corpus:check` converges.

## Related

<CardGroup cols={2}>
  <Card title="Benchmarks" icon="gauge" href="/docs/benchmarks">
    See timing and correctness evidence.
  </Card>

  <Card title="Support matrix" icon="table" href="/docs/reference/support-matrix">
    Check which PostgreSQL objects are modeled.
  </Card>

  <Card title="Check command" icon="shield-check" href="/docs/commands/check">
    Validate rendered corpus migrations.
  </Card>

  <Card title="Verify command" icon="repeat-2" href="/docs/commands/verify">
    Compare apply-twice behavior against the declarative tree.
  </Card>
</CardGroup>