[Bug] Vec<u8> is recognised as Array rather than Bytes

[dracarys18]

Fred version - 9.2.1
Redis version - 7.0.1
Platform - mac
Deployment type - cluster|sentinel|centralized

Describe the bug
For the following example below, Fred throws and error value: Redis Error - kind: InvalidArgument, details: Invalid argument type: Array while it's a valid type.

    let v = client.hsetnx::<E, &str, &str, V>("bruh1", "what1", serde_json::to_vec(&data).unwrap()).await;

To Reproduce
Steps to reproduce the behavior:

1. Call hsetnx function with Vec<u8> as value type.

Logs
(If possible set RUST_LOG=fred=trace and run with --features debug-ids)

Redis Error - kind: InvalidArgument, details: Invalid argument type: Array

[dracarys18]

I can take this up we need a different TryInto implementation for Vec<u8> and Vec<T> where T is not u8

[aembke]

Hi @dracarys18,

Unfortunately I'm not sure how to do this on stable rust at the moment without specialization, but feel free to submit a PR if you can make it work.

After looking at this a bit more - If I'm reading this correctly it looks like TryFrom<T> creates a From<T> fallback automatically, and since From<u8> already exists we can't implement both TryFrom<Vec<u8>> for RedisValue and TryFrom<Vec<T>> for RedisValue.

I think there's a few ways to work around this, but they have some downsides:

• Convert to Vec<RedisValue::Integer> and back to bytes (safe but expensive)
• Wait for specialization (unstable at the moment)
• Remove the From<u8> for RedisValue impl (breaking)
• Use mem::transmute (unsafe, and probably not useful since it would have to be used with TypeId::of(), which requires T: 'static, which is breaking)
• Use a different trait other than TryFrom to do these type conversions so we can detect Vec<u8> in the same manner that FromRedis uses (breaking)

For the next major version I'll probably remove the From<u8> for RedisValue since Vec<u8> is likely much more common, but for now I want to avoid any breaking changes.

[dracarys18]

@aembke I like the idea of last point can we make a feature flag for this so it wont break for others and slowly release it in the next release

[aembke]

Sounds good. In 9.4.0 there a new FF specialize-into-bytes that will disable From<u8> for RedisValue and enable TryFrom<Vec<u8>> for RedisValue such that it uses RedisValue::Bytes.

[dracarys18]

Oh that's awesome! Thanks @aembke

[aembke]

Added in 9.4.0