feat: auto use transaction in db.query (#5)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Enhanced database query flexibility by allowing the use of
transactions or specific connections.

- **Tests**
- Implemented new tests to verify database queries within transactions
and with specified connections.

- **Chores**
	- Updated `.gitignore` to exclude IDE-specific settings files.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: killagu

Diff for: .gitignore

@@ -16,3 +16,4 @@ coverage
 lib
 .eslintcache
 package-lock.json
+.idea

Diff for: src/client.ts

@@ -25,6 +25,10 @@ interface PoolPromisify extends Omit<Pool, 'query'> {
   };
 }
 
+export interface QueryOptions {
+  conn?: RDSConnection | RDSTransaction;
+}
+
 export class RDSClient extends Operator {
   static get literals() { return literals; }
   static get escape() { return mysql.escape; }
@@ -83,12 +87,28 @@ export class RDSClient extends Operator {
     });
   }
 
-  async query<T = any>(sql: string, values?: object | any[]): Promise<T> {
-    const conn = await this.getConnection();
+  async query<T = any>(sql: string, values?: object | any[], options?: QueryOptions): Promise<T> {
+    let conn: RDSConnection | RDSTransaction;
+    let shouldReleaseConn = false;
+    if (options?.conn) {
+      conn = options.conn;
+    } else {
+      const ctx = this.#connectionStorage.getStore();
+      const ctxConn = ctx?.[this.#connectionStorageKey];
+      if (ctxConn) {
+        conn = ctxConn;
+      } else {
+        conn = await this.getConnection();
+        shouldReleaseConn = true;
+      }
+    }
+
     try {
       return await conn.query(sql, values);
     } finally {
-      conn.release();
+      if (shouldReleaseConn) {
+        (conn as RDSConnection).release();
+      }
     }
   }
 

Diff for: test/client.test.ts

@@ -647,6 +647,42 @@ describe('test/client.test.ts', () => {
       await db1.end();
       await db2.end();
     });
+
+    it('should db.query in transaction scope works', async () => {
+      let querySql: string | undefined;
+      mm(RDSTransaction.prototype, 'query', async (sql: string) => {
+        querySql = sql;
+      });
+      await db.beginTransactionScope(async () => {
+        await db.query(`insert into ??(name, email, gmt_create, gmt_modified)
+            values(?, ?, now(), now())`,
+        [ table, prefix + 'multiple-instance1', prefix + '[email protected]' ]);
+        return db;
+      });
+      assert(querySql);
+    });
+
+    it('should db.query specify conn in transaction scope works', async () => {
+      let transactionQuerySql: string | undefined;
+      let connQuerySql: string | undefined;
+      mm(RDSTransaction.prototype, 'query', async (sql: string) => {
+        transactionQuerySql = sql;
+      });
+      const conn = await db.getConnection();
+      mm(conn, 'query', async (sql: string) => {
+        connQuerySql = sql;
+      });
+      await db.beginTransactionScope(async () => {
+        await db.query(`insert into ??(name, email, gmt_create, gmt_modified)
+            values(?, ?, now(), now())`,
+        [ table, prefix + 'multiple-instance1', prefix + '[email protected]' ], {
+          conn,
+        });
+        return db;
+      });
+      assert(connQuerySql);
+      assert(!transactionQuerySql);
+    });
   });
 
   describe('beginDoomedTransactionScope(scope)', () => {