fix: ping return bulk string

src/redis_cmd.cc

@@ -242,7 +242,13 @@ class CommandFlushAll : public Commander {
 class CommandPing : public Commander {
  public:
   Status Execute(Server *svr, Connection *conn, std::string *output) override {
-    *output = Redis::SimpleString("PONG");
+    if (args_.size() == 1) {
+      *output = Redis::SimpleString("PONG");
+    } else if (args_.size() == 2) {
+      *output = Redis::BulkString(args_[1]);
+    } else {
+      return Status(Status::NotOK, errWrongNumOfArguments);
+    }
     return Status::OK();
   }
 };
@@ -5833,7 +5839,7 @@ class CommandXTrim : public Commander {
 
 CommandAttributes redisCommandTable[] = {
     ADD_CMD("auth", 2, "read-only ok-loading", 0, 0, 0, CommandAuth),
-    ADD_CMD("ping", 1, "read-only", 0, 0, 0, CommandPing),
+    ADD_CMD("ping", -1, "read-only", 0, 0, 0, CommandPing),
     ADD_CMD("select", 2, "read-only", 0, 0, 0, CommandSelect),
     ADD_CMD("info", -1, "read-only ok-loading", 0, 0, 0, CommandInfo),
     ADD_CMD("role", 1, "read-only ok-loading", 0, 0, 0, CommandRole),

tests/gocase/unit/introspection/introspection_test.go

@@ -0,0 +1,52 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package command
+
+import (
+	"testing"
+
+	"github.com/apache/incubator-kvrocks/tests/gocase/util"
+	"github.com/stretchr/testify/require"
+)
+
+func TestIntrospection(t *testing.T) {
+	srv := util.StartServer(t, map[string]string{})
+	defer srv.Close()
+
+	t.Run("PING", func(t *testing.T) {
+		c := srv.NewTCPClient()
+		defer func() { require.NoError(t, c.Close()) }()
+		require.NoError(t, c.WriteArgs("PING"))
+		r, err := c.ReadLine()
+		require.NoError(t, err)
+		require.Equal(t, r, "+PONG")
+		require.NoError(t, c.WriteArgs("PING", "PONG"))
+		r, err = c.ReadLine()
+		require.NoError(t, err)
+		require.Equal(t, r, "$4")
+		r, err = c.ReadLine()
+		require.NoError(t, err)
+		require.Equal(t, r, "PONG")
+		require.NoError(t, c.WriteArgs("ping", "hello", "redis"))
+		r, err = c.ReadLine()
+		require.NoError(t, err)
+		require.Equal(t, r, "-ERR wrong number of arguments")
+	})
+}