/**
 * Tool-discriminated boot-time gate: verify a relational database's
 * latest-by-name applied migration matches the expected version baked into
 * the deployed image. Companion to {@link pickLatestPrismaMigration} (which
 * resolves the expected version FROM disk at synth/runner time); this
 * helper closes the loop by reading what the DB actually has APPLIED.
 *
 * "Latest" MUST mean lexicographic max of migration_name, mirroring
 * pickLatestPrismaMigration — NOT most recently finished. Prisma's
 * `migrate deploy` applies a pending migration even when it name-sorts
 * before already-applied ones (parallel branches landing interleaved
 * timestamps), so latest-by-finished_at can be an OLDER name than what the
 * schema actually satisfies, false-failing the gate against a complete DB.
 *
 * Consumer supplies the driver via the {@link MigrationsSqlClient} shim so
 * the package stays driver-agnostic (pg, mysql2, postgres.js, Drizzle
 * session, raw Prisma `$queryRawUnsafe`, …). The shim's single `query(sql)`
 * surface is intentionally narrower than any real driver — callers wrap.
 *
 * Two tool branches today:
 *  - `tool: "prisma"` reads `_prisma_migrations.migration_name` (max name
 *    among `finished_at IS NOT NULL`). Stable across all Prisma DB engines.
 *  - `tool: "custom"` lets a caller pass a `{ sql, column }` pair when the
 *    migration tool's metadata table doesn't match the Prisma shape (e.g.
 *    Drizzle's `__drizzle_migrations.hash`, Knex's `knex_migrations.name`).
 *
 * Returns `{ matches, expected, actual }` rather than throwing on mismatch:
 * the boot gate's caller owns the exit-code / log shape so the helper can
 * be reused by integration tests, dashboards, and CLI checks alike.
 *
 * `matches` tolerates expand-only rollback: an old image booting against a
 * NEWER applied schema passes (`actual >= expected`), while the forward
 * direction (new code against an older schema) still fails. The comparison is
 * delegated to `isSchemaVersionSatisfied` — see it for the orderability rules.
 */
/**
 * Minimal SQL-driver shim. Compatible with `pg.Client.query`, `mysql2.query`,
 * `postgres()(sql)`, and Drizzle's `db.session.execute()` via a thin adapter.
 */
export interface MigrationsSqlClient {
    query(sql: string): Promise<{
        rows: ReadonlyArray<Record<string, unknown>>;
    }>;
}
export interface VerifyExpectedSchemaVersionOpts {
    /** Migration tool whose metadata table to inspect. */
    tool: "prisma" | "custom";
    /** Expected version (typically read from an env var baked into the image). */
    expected: string;
    /** SQL driver shim. Consumer owns connection lifecycle. */
    client: MigrationsSqlClient;
    /** Abort signal honoured before the query is issued. */
    signal?: AbortSignal;
    /**
     * Required when `tool: "custom"`. `sql` MUST return a single row whose
     * `column` holds the latest applied migration's name/hash.
     */
    customQuery?: {
        sql: string;
        column: string;
    };
}
export interface VerifyExpectedSchemaVersionResult {
    matches: boolean;
    expected: string;
    /** `null` when no migrations have been applied (empty result set). */
    actual: string | null;
}
export declare function verifyExpectedSchemaVersion(opts: VerifyExpectedSchemaVersionOpts): Promise<VerifyExpectedSchemaVersionResult>;