Breaking Change

[zebede22]

I recently upgraded my redis crate from version 0.23 to 0.24. Previously, the following code snippet was working fine:

static CLIENT: Lazy<Client> =
    Lazy::new(|| Client::open("redis://xxx:1234").expect("Failed to connect to redis"));

pub async fn get_json(key: &str) -> RedisResult<Value> {
    let mut conn = CLIENT.get_tokio_connection().await?;
    let Json(json_data) = conn.json_get(key, "$").await?;

    Ok(json_data)
}

However, after upgrading to version 0.24, I started receiving an error message without making any changes to the code. Can anyone explain what might have caused this issue?

error[E0277]: the trait bound `redis_macros::Json<_>: FromRedisValue` is not satisfied
   --> src/redis.rs:14:32
    |
14  |     let Json(json_data) = conn.json_get(key, "$").await?;
    |                                ^^^^^^^^ the trait `FromRedisValue` is not implemented for `redis_macros::Json<_>`
    |
    = help: the following other types implement trait `FromRedisValue`:
              bool
              isize
              i8
              i16
              i32
              i64
              i128
              usize
            and 44 others
note: required by a bound in `redis::JsonAsyncCommands::json_get`
   --> /home/ubuntu/.cargo/registry/src/index.crates.io-6f17d22bba15001f/redis-0.24.0/src/commands/json.rs:177:1
    |
177 | / implement_json_commands! {
178 | |     'a
179 | |     
180 | |     /// Append the JSON `value` to the array at `path` after the last element in it.
...   |
298 | |     fn json_get<K: ToRedisArgs, P: ToRedisArgs>(key: K, path: P) {
    | |        -------- required by a bound in this associated function
...   |
388 | |     }
389 | | }
    | |_^ required by this bound in `JsonAsyncCommands::json_get`
    = note: this error originates in the macro `implement_json_commands` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0277`.

[zebede22]

^^^^^^^^ the trait `FromRedisValue` is not implemented for `serde_json::Value`

If I specify type it works let json_data: String, but I don't know the structure, it's a json data, so it's serde_json::Value

[nihohit]

@zebede22 are you sure this isn't an issue with the redis-macros crate? can you provide an example that relies only on redis-rs?

[zebede22]

@zebede22 are you sure this isn't an issue with the redis-macros crate? can you provide an example that relies only on redis-rs?

Yes, redis-rs is not related.
Here same code without the redis-crate:

 let json_data: Value = conn.json_get(key, "$").await?;

Error:

error[E0277]: the trait bound `serde_json::Value: FromRedisValue` is not satisfied
   --> src/redis.rs:14:33
    |
14  |     let json_data: Value = conn.json_get(key, "$").await?;
    |                                 ^^^^^^^^ the trait `FromRedisValue` is not implemented for `serde_json::Value`
    |
    = help: the following other types implement trait `FromRedisValue`:
              bool
              isize
              i8
              i16
              i32
              i64
              i128
              usize
            and 44 others
note: required by a bound in `redis::JsonAsyncCommands::json_get`

[nihohit]

is serde_json::Value supposed to implement FromRedisValue? if so, where is it implemented?
Again, that's not a redis-rs type, so it's hard for me to understand whether this is an issue in redis-rs or not.

[zebede22]

is serde_json::Value supposed to implement FromRedisValue? if so, where is it implemented? Again, that's not a redis-rs type, so it's hard for me to understand whether this is an issue in redis-rs or not.

It's been working until 0.24 change.

Also, how to get a json from an endpoint where you have no exact json structure? how it can be done without serde_json?

[nihohit]

how to get a json from an endpoint where you have no exact json structure? how it can be done without serde_json?

You can use a HashMap, or a string. We're trying to understand what changed, and the more moving parts there are, the harder it is to pinpoint the source of the issue.

It's been working until 0.24 change.

Maybe, but I need a minimal reproducible example in order to understand the issue. If you want to create a small project to simulate the problem, that will be very helpful.

[Dav1dde]

Sounds like you have two separate versions of redis in your dependency tree. Looking at the redis-macros crate it does infact have redis version 0.23 as a dependency which is not semver compatible with 0.24.

-> Not related to the redis crate, you just need to use the same version or ask redis-marcros to update the dependency.

[samgj18]

This is still happening, just happened to me after upgrading. I believe this is a redis-rs issue rather than another lib issue.

[Dav1dde]

Check your Cargo.lock or cargo tree, it is very likely you have two separate versions of the redis crate in your dependencies.

[samgj18]

I went over both before trying to find a solution here. What I thought could be the culprit, deadpool-redis, also has the same dep [see here](https://github.com/bikeshedder/deadpool/blob/master/redis/Cargo.toml#L40).

[nihohit]

@zebede22 does this still happen? can you provide a reproducing example?