Question: does `smol` have something similar to `tokio::task_local!` and `async_std::task_local!`?

[al8n]

Hi, does smol have something similar to tokio::task_local! and async_std::task_local!? If not, any suggestions about how to achieve this in smol?

[notgull]

The intent is for task metadata to be used as task-local storage. However, this isn't available in the current smol::Executor yet. Please file an issue on async-executor if this is desired.

[nanoqsh]

I think it's worth reconsidering the necessity of this feature.
Usually if I need to attach some data to a task, I just move it to a future and use it inside. Perhaps there are some special cases when such a feature is required, I'd like to see examples

[al8n]

I think it's worth reconsidering the necessity of this feature. Usually if I need to attach some data to a task, I just move it to a future and use it inside. Perhaps there are some special cases when such a feature is required, I'd like to see examples

Let's consider this example: you have a struct that is frequently serialized; a task local can help you avoid unnecessary allocation.

struct H256([u8; _]);

impl Serialize for H256 {
   fn serialize(&self, ..) -> .. {
      static TASK_LOCAL_BUF: ... = {
         String::with_capacity(cap)
      };

      TASK_LOCAL_BUF.with_mut(|buf| {
          self.write_to_buf(buf);
          // DO the serialize
      })
   }
}

It's true you can declare the BUF in a task, and use more complex code to achieve it, but if a task local is there, it can make life easier.