Using GET to get json type key will not return error.

[jihuayu]

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• I had searched in the issues and found no similar issues.

Version

unstable

Minimal reproduce step

Using GET to get json type key will not return error.
I writed below test case.

t.Run("GET JSON type key", func(t *testing.T) {
	require.NoError(t, rdb.Do(ctx, "JSON.SET", "a", "$", ` {"x":1,"y":2} `).Err())
	require.EqualValues(t, "\x00{\"x\":1,\"y\":2}", rdb.Get(ctx, "a").Val())
})

What did you expect to see?

test failed

What did you see instead?

test Passed

Anything Else?

Maybe is this line problem.https://github.com/apache/kvrocks/blob/unstable/src/types/redis_string.cc#L86

if (metadata.Type() != kRedisString && metadata.size > 0) {
    return rocksdb::Status::InvalidArgument(kErrMsgWrongType);
  }

Why do we need to check metadata.size > 0?

Are you willing to submit a PR?

• I'm willing to submit a PR!

[git-hulk]

@jihuayu Good catch!

Why do we need to check metadata.size > 0?

For example, we need to regard it as a non-existing key if all subkeys are deleted in a list(same as the hash/set/zset). But some types allow the empty subkey list like stream/bloomfilter. Can refer: storage/redis_db.cc#L62

The better way is to use GetMetadata to replace the decode function in redis_string.

[jihuayu]

Fixed after #1971