ScopedJoinSet

A lifetime-aware wrapper around [tokio::task::JoinSet] for spawning scoped async tasks in Rust.

ScopedJoinSet focuses on correct task semantics for non-'static futures. It ensures that each spawned task:

• Completes exactly once, and its output can be collected in completion order.
• Cannot outlive the lifetime of references it captures ('scope).
• Can be cancelled, aborted, or collected deterministically.

Unlike standard Tokio tasks, which require 'static futures, this crate enables advanced async orchestration where tasks depend on temporary stack data, while guaranteeing predictable task lifetimes and output delivery.

Recommendation: Prefer using shutdown().await instead of relying on Drop to terminate tasks. This allows the runtime to complete tasks asynchronously. Dropping the set will block the current thread with a spin loop (block_in_place) on multithreaded runtimes, which may interfere with other tasks.

Features

• Spawn futures with non-'static lifetimes.
• Cancellation-safe task joining with join_next or try_join_next.
• Automatic cleanup on drop: aborts all running tasks.
• Supports both awaited and non-blocking task collection.
• Graceful shutdown of all tasks via shutdown().
• Memory-safe, even under Miri.

Installation

Add to your Cargo.toml:

[dependencies]
scoped-join-set = "0.4"
tokio = { version = "1", features = ["full"] }

License

MIT OR Apache-2.0

⚠️ Warning

This crate has not undergone formal peer review or extensive production testing. While it has been tested for basic correctness and memory safety (including Miri), use in critical systems or untrusted environments carries risk.

Use at your own discretion and thoroughly test in your own context before deploying.