feat: add @objectstack/driver-turso extending SqlDriver with zero CRUD duplication

CHANGELOG.md

@@ -7,6 +7,35 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- **`@objectstack/driver-turso` plugin** — Migrated and standardized the Turso/libSQL driver from
+  `@objectql/driver-turso` into `packages/plugins/driver-turso/`. The driver **extends** `SqlDriver`
+  from `@objectstack/driver-sql` — all CRUD, schema, filter, aggregation, and introspection logic
+  is inherited with zero code duplication. Turso-specific features include: three connection modes
+  (local file, in-memory, embedded replica), `@libsql/client` sync mechanism for embedded replicas,
+  multi-tenant router with TTL-based driver caching, and enhanced capability flags (FTS5, JSON1,
+  CTE, savepoints, indexes). Includes 53 unit tests. Factory function `createTursoDriver()` and
+  plugin manifest for kernel integration.
+- **Multi-tenant routing** (`createMultiTenantRouter`) — Database-per-tenant architecture with
+  automatic driver lifecycle management, tenant ID validation, configurable TTL cache, and
+  `onTenantCreate`/`onTenantEvict` lifecycle callbacks. Serverless-safe (no global intervals).
+
+### Changed
+- **`@objectstack/driver-sql` — Protected extensibility** — Changed `private` to `protected` for
+  all internal properties and methods (`knex`, `config`, `jsonFields`, `booleanFields`,
+  `tablesWithTimestamps`, `isSqlite`, `isPostgres`, `isMysql`, `getBuilder`, `applyFilters`,
+  `applyFilterCondition`, `mapSortField`, `mapAggregateFunc`, `buildWindowFunction`,
+  `createColumn`, `ensureDatabaseExists`, `createDatabase`, `isJsonField`, `formatInput`,
+  `formatOutput`, `introspectColumns`, `introspectForeignKeys`, `introspectPrimaryKeys`,
+  `introspectUniqueConstraints`). Enables clean subclassing for driver variants (Turso, D1, etc.)
+  without code duplication.
+
+### Fixed
+- **`@objectstack/driver-sql` — `count()` returns NaN for zero results** — Fixed `count()` method
+  using `||` (logical OR) instead of `??` (nullish coalescing) to read the count value. When the
+  actual count was `0`, `row.count || row['count(*)']` evaluated to `Number(undefined)` = `NaN`
+  because `0` is falsy. Now uses `row.count ?? row['count(*)'] ?? 0` for correct zero handling.
+
 ### Changed
 - **Unified Data Driver Contract (`IDataDriver`)** — Resolved the split between `DriverInterface`
   (core, minimal ~13 methods) and `IDataDriver` (spec, comprehensive 28 methods). `IDataDriver`

ROADMAP.md

@@ -44,6 +44,8 @@ the ecosystem for enterprise workloads.
 | Microkernel (ObjectKernel / LiteKernel) | ✅ | `@objectstack/core` |
 | Data Engine (ObjectQL) | ✅ | `@objectstack/objectql` |
 | In-Memory Driver | ✅ | `@objectstack/driver-memory` |
+| SQL Driver (PostgreSQL, MySQL, SQLite) | ✅ | `@objectstack/driver-sql` |
+| Turso/libSQL Driver (Edge SQLite) | ✅ | `@objectstack/driver-turso` |
 | Metadata Service | ✅ | `@objectstack/metadata` |
 | REST API Server | ✅ | `@objectstack/rest` |
 | Client SDK (TypeScript) | ✅ | `@objectstack/client` |

packages/plugins/driver-sql/src/sql-driver-queryast.test.ts

@@ -144,7 +144,7 @@ describe('SqlDriver (QueryAST Format)', () => {
       const results = await driver.find('products', {
         fields: ['name'],
         limit: 2,
-        orderBy: [['price', 'asc']],
+        orderBy: [{ field: 'price', order: 'asc' }],
       } as any);
 
       expect(results.length).toBe(2);

packages/plugins/driver-sql/src/sql-driver.ts

@@ -65,8 +65,8 @@ export type SqlDriverConfig = Knex.Config;
  */
 export class SqlDriver implements IDataDriver {
   // IDataDriver metadata
-  public readonly name = 'com.objectstack.driver.sql';
-  public readonly version = '1.0.0';
+  public readonly name: string = 'com.objectstack.driver.sql';
+  public readonly version: string = '1.0.0';
   public readonly supports = {
     // Basic CRUD Operations
     create: true,
@@ -113,26 +113,26 @@ export class SqlDriver implements IDataDriver {
     queryCache: false,
   };
 
-  private knex: Knex;
-  private config: Knex.Config;
-  private jsonFields: Record<string, string[]> = {};
-  private booleanFields: Record<string, string[]> = {};
-  private tablesWithTimestamps: Set<string> = new Set();
+  protected knex: Knex;
+  protected config: Knex.Config;
+  protected jsonFields: Record<string, string[]> = {};
+  protected booleanFields: Record<string, string[]> = {};
+  protected tablesWithTimestamps: Set<string> = new Set();
 
   /** Whether the underlying database is a SQLite variant (sqlite3 or better-sqlite3). */
-  private get isSqlite(): boolean {
+  protected get isSqlite(): boolean {
     const c = (this.config as any).client;
     return c === 'sqlite3' || c === 'better-sqlite3';
   }
 
   /** Whether the underlying database is PostgreSQL. */
-  private get isPostgres(): boolean {
+  protected get isPostgres(): boolean {
     const c = (this.config as any).client;
     return c === 'pg' || c === 'postgresql';
   }
 
   /** Whether the underlying database is MySQL. */
-  private get isMysql(): boolean {
+  protected get isMysql(): boolean {
     const c = (this.config as any).client;
     return c === 'mysql' || c === 'mysql2';
   }
@@ -185,10 +185,8 @@ export class SqlDriver implements IDataDriver {
     // ORDER BY
     if (query.orderBy && Array.isArray(query.orderBy)) {
       for (const item of query.orderBy) {
-        const field = item.field || item[0];
-        const dir = item.order || item[1] || 'asc';
-        if (field) {
-          builder.orderBy(this.mapSortField(field), dir);
+        if (item.field) {
+          builder.orderBy(this.mapSortField(item.field), item.order || 'asc');
         }
       }
     }
@@ -364,7 +362,7 @@ export class SqlDriver implements IDataDriver {
     const result = await builder.count<{ count: number }[]>('* as count');
     if (result && result.length > 0) {
       const row: any = result[0];
-      return Number(row.count || row['count(*)']);
+      return Number(row.count ?? row['count(*)'] ?? 0);
     }
     return 0;
   }
@@ -702,7 +700,7 @@ export class SqlDriver implements IDataDriver {
     return this.knex;
   }
 
-  private getBuilder(object: string, options?: DriverOptions) {
+  protected getBuilder(object: string, options?: DriverOptions) {
     let builder = this.knex(object);
     if (options?.transaction) {
       builder = builder.transacting(options.transaction as Knex.Transaction);
@@ -712,7 +710,7 @@ export class SqlDriver implements IDataDriver {
 
   // ── Filter helpers ──────────────────────────────────────────────────────────
 
-  private applyFilters(builder: Knex.QueryBuilder, filters: any) {
+  protected applyFilters(builder: Knex.QueryBuilder, filters: any) {
     if (!filters) return;
 
     if (!Array.isArray(filters) && typeof filters === 'object') {
@@ -793,7 +791,7 @@ export class SqlDriver implements IDataDriver {
     }
   }
 
-  private applyFilterCondition(builder: Knex.QueryBuilder, condition: any, logicalOp: 'and' | 'or' = 'and') {
+  protected applyFilterCondition(builder: Knex.QueryBuilder, condition: any, logicalOp: 'and' | 'or' = 'and') {
     if (!condition || typeof condition !== 'object') return;
 
     for (const [key, value] of Object.entries(condition)) {
@@ -864,13 +862,13 @@ export class SqlDriver implements IDataDriver {
 
   // ── Field mapping ───────────────────────────────────────────────────────────
 
-  private mapSortField(field: string): string {
+  protected mapSortField(field: string): string {
     if (field === 'createdAt') return 'created_at';
     if (field === 'updatedAt') return 'updated_at';
     return field;
   }
 
-  private mapAggregateFunc(func: string): string {
+  protected mapAggregateFunc(func: string): string {
     switch (func) {
       case 'count':
         return 'count';
@@ -889,7 +887,7 @@ export class SqlDriver implements IDataDriver {
 
   // ── Window function builder ─────────────────────────────────────────────────
 
-  private buildWindowFunction(spec: any): string {
+  protected buildWindowFunction(spec: any): string {
     const func = spec.function.toUpperCase();
     let sql = `${func}()`;
 
@@ -917,7 +915,7 @@ export class SqlDriver implements IDataDriver {
 
   // ── Column creation helper ──────────────────────────────────────────────────
 
-  private createColumn(table: Knex.CreateTableBuilder, name: string, field: any) {
+  protected createColumn(table: Knex.CreateTableBuilder, name: string, field: any) {
     if (field.multiple) {
       table.json(name);
       return;
@@ -996,7 +994,7 @@ export class SqlDriver implements IDataDriver {
 
   // ── Database helpers ────────────────────────────────────────────────────────
 
-  private async ensureDatabaseExists() {
+  protected async ensureDatabaseExists() {
     if (!this.isPostgres) return;
 
     try {
@@ -1010,7 +1008,7 @@ export class SqlDriver implements IDataDriver {
     }
   }
 
-  private async createDatabase() {
+  protected async createDatabase() {
     const config = this.config as any;
     const connection = config.connection;
     let dbName = '';
@@ -1034,13 +1032,13 @@ export class SqlDriver implements IDataDriver {
     }
   }
 
-  private isJsonField(type: string, field: any): boolean {
+  protected isJsonField(type: string, field: any): boolean {
     return ['json', 'object', 'array', 'image', 'file', 'avatar', 'location'].includes(type) || field.multiple;
   }
 
   // ── SQLite serialisation ────────────────────────────────────────────────────
 
-  private formatInput(object: string, data: any): any {
+  protected formatInput(object: string, data: any): any {
     if (!this.isSqlite) return data;
 
     const fields = this.jsonFields[object];
@@ -1055,7 +1053,7 @@ export class SqlDriver implements IDataDriver {
     return copy;
   }
 
-  private formatOutput(object: string, data: any): any {
+  protected formatOutput(object: string, data: any): any {
     if (!data) return data;
 
     if (this.isSqlite) {
@@ -1087,7 +1085,7 @@ export class SqlDriver implements IDataDriver {
 
   // ── Introspection internals ─────────────────────────────────────────────────
 
-  private async introspectColumns(tableName: string): Promise<IntrospectedColumn[]> {
+  protected async introspectColumns(tableName: string): Promise<IntrospectedColumn[]> {
     const columnInfo = await this.knex(tableName).columnInfo();
     const columns: IntrospectedColumn[] = [];
 
@@ -1119,7 +1117,7 @@ export class SqlDriver implements IDataDriver {
     return columns;
   }
 
-  private async introspectForeignKeys(tableName: string): Promise<IntrospectedForeignKey[]> {
+  protected async introspectForeignKeys(tableName: string): Promise<IntrospectedForeignKey[]> {
     const foreignKeys: IntrospectedForeignKey[] = [];
 
     try {
@@ -1205,7 +1203,7 @@ export class SqlDriver implements IDataDriver {
     return foreignKeys;
   }
 
-  private async introspectPrimaryKeys(tableName: string): Promise<string[]> {
+  protected async introspectPrimaryKeys(tableName: string): Promise<string[]> {
     const primaryKeys: string[] = [];
 
     try {
@@ -1265,7 +1263,7 @@ export class SqlDriver implements IDataDriver {
     return primaryKeys;
   }
 
-  private async introspectUniqueConstraints(tableName: string): Promise<string[]> {
+  protected async introspectUniqueConstraints(tableName: string): Promise<string[]> {
     const uniqueColumns: string[] = [];
 
     try {