fix #2046 - add support for multi in select (#2133)

* fix #2046 - add support for multi in select

* fix "Argument of type 'symbol | undefined' is not assignable to parameter of type 'number | undefined'"

packages/client/lib/client/index.spec.ts

@@ -468,6 +468,20 @@ describe('Client', () => {
                 ['PONG']
             );
         }, GLOBAL.SERVERS.OPEN);
+
+        testUtils.testWithClient('should remember selected db', async client => {
+            await client.multi()
+                .select(1)
+                .exec();
+            await killClient(client);
+            assert.equal(
+                (await client.clientInfo()).db,
+                1
+            );
+        }, {
+            ...GLOBAL.SERVERS.OPEN,
+            minimumDockerVersion: [6, 2] // CLIENT INFO
+        });
     });
 
     testUtils.testWithClient('scripts', async client => {

packages/client/lib/client/index.ts

@@ -606,18 +606,26 @@ export default class RedisClient<
         );
     }
 
-    multiExecutor(commands: Array<RedisMultiQueuedCommand>, chainId?: symbol): Promise<Array<RedisCommandRawReply>> {
+    async multiExecutor(
+        commands: Array<RedisMultiQueuedCommand>,
+        selectedDB?: number,
+        chainId?: symbol
+    ): Promise<Array<RedisCommandRawReply>> {
         const promise = Promise.all(
             commands.map(({ args }) => {
-                return this.#queue.addCommand(args, RedisClient.commandOptions({
-                    chainId
-                }));
+                return this.#queue.addCommand(args, { chainId });
             })
         );
 
         this.#tick();
 
-        return promise;
+        const results = await promise;
+
+        if (selectedDB !== undefined) {
+            this.#selectedDB = selectedDB;
+        }
+
+        return results;
     }
 
     async* scanIterator(options?: ScanCommandOptions): AsyncIterable<string> {

packages/client/lib/client/multi-command.ts

@@ -58,13 +58,13 @@ type InstantiableRedisMultiCommand<
     S extends RedisScripts
 > = new (...args: ConstructorParameters<typeof RedisClientMultiCommand>) => RedisClientMultiCommandType<M, F, S>;
 
-
-export type RedisClientMultiExecutor = (queue: Array<RedisMultiQueuedCommand>, chainId?: symbol) => Promise<Array<RedisCommandRawReply>>;
+export type RedisClientMultiExecutor = (
+    queue: Array<RedisMultiQueuedCommand>,
+    selectedDB?: number,
+    chainId?: symbol
+) => Promise<Array<RedisCommandRawReply>>;
 
 export default class RedisClientMultiCommand {
-    readonly #multi = new RedisMultiCommand();
-    readonly #executor: RedisClientMultiExecutor;
-
     static extend<
         M extends RedisModules,
         F extends RedisFunctions,
@@ -81,7 +81,10 @@ export default class RedisClientMultiCommand {
         });
     }
 
+    readonly #multi = new RedisMultiCommand();
+    readonly #executor: RedisClientMultiExecutor;
     readonly v4: Record<string, any> = {};
+    #selectedDB?: number;
 
     constructor(executor: RedisClientMultiExecutor, legacyMode = false) {
         this.#executor = executor;
@@ -136,6 +139,13 @@ export default class RedisClientMultiCommand {
         );
     }
 
+    SELECT(db: number, transformReply?: RedisCommand['transformReply']): this {
+        this.#selectedDB = db;
+        return this.addCommand(['SELECT', db.toString()], transformReply);
+    }
+
+    select = this.SELECT;
+
     addCommand(args: RedisCommandArguments, transformReply?: RedisCommand['transformReply']): this {
         this.#multi.addCommand(args, transformReply);
         return this;
@@ -160,7 +170,11 @@ export default class RedisClientMultiCommand {
         if (!commands) return [];
 
         return this.#multi.handleExecReplies(
-            await this.#executor(commands, RedisMultiCommand.generateChainId())
+            await this.#executor(
+                commands,
+                this.#selectedDB,
+                RedisMultiCommand.generateChainId()
+            )
         );
     }
 
@@ -168,7 +182,10 @@ export default class RedisClientMultiCommand {
 
     async execAsPipeline(): Promise<Array<RedisCommandRawReply>> {
         return this.#multi.transformReplies(
-            await this.#executor(this.#multi.queue)
+            await this.#executor(
+                this.#multi.queue,
+                this.#selectedDB
+            )
         );
     }
 }

packages/client/lib/cluster/index.ts

@@ -230,7 +230,7 @@ export default class RedisCluster<
                 return this.#execute(
                     firstKey,
                     false,
-                    client => client.multiExecutor(commands, chainId)
+                    client => client.multiExecutor(commands, undefined, chainId)
                 );
             },
             routing