futures-channel 0.3.34

# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
version = 4

[[package]]
name = "futures-channel"
version = "0.3.34"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b1f9e3d69d39e4862ffed03ed071a76f9a13ba1d9109d355b0f0aa6b15e393c4"
dependencies = [
 "futures-core",
]

[[package]]
name = "futures-core"
version = "0.3.34"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "92d699e522242e69e3003b94ecc1f960f3a5e015aa7c5d7486e65ad01dd94f5e"

[[package]]
name = "sample-futures-channel"
version = "1.0.0"
dependencies = [
 "futures-channel",
]

[package]
name = "sample-futures-channel"
version = "1.0.0"
edition = "2021"
publish = false

[dependencies]
futures-channel = "=0.3.34"

[[bin]]
name = "contract"
path = "test/contract.rs"

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:cargo/futures-channel@0.3.34
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:cargo/futures-channel@0.3.34

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:4435b732d48ed71704906ef530e91dc27d3b5188abc7aab423e30ec1fbb914ab","contract":["oneshot::channel transmits a single value successfully from Sender to Receiver","oneshot::channel signals Canceled when Sender is dropped without sending","oneshot::Receiver::close marks channel complete and Sender is_canceled returns true","mpsc::unbounded transmits multiple values in FIFO order via unbounded_send and try_recv","mpsc::channel with capacity limit returns TrySendError full when buffer is exhausted","mpsc::Receiver::close closes the channel causing subsequent try_send to fail with disconnected"],"goal":"verify pkg:cargo/futures-channel@0.3.34","kind":"HOW","packages":["pkg:cargo/futures-channel@0.3.34"],"schemaVersion":1},"contractCommand":["cargo","run","--offline"],"environment":{"arch":"x64","distro":"alpine","ecosystem":"cargo","libc":"musl","os":"linux","packageManager":"cargo","schemaVersion":1},"license":"MIT-0","packages":["pkg:cargo/futures-channel@0.3.34"],"schemaVersion":1,"subject":"pkg:cargo/futures-channel@0.3.34","verifierAdapter":"cargo@1"}

{
  "schemaVersion": 1,
  "goal": "verify pkg:cargo/futures-channel@0.3.34",
  "kind": "HOW",
  "packages": [
    "pkg:cargo/futures-channel@0.3.34"
  ]
}

//! Clean-room verification sample for futures-channel.

pub use futures_channel::*;

use futures_channel::mpsc::{self, TryRecvError};
use futures_channel::oneshot;

fn main() {
    // 1. oneshot::channel transmits a single value successfully from Sender to Receiver
    {
        let (tx, mut rx) = oneshot::channel::<i32>();
        assert_eq!(rx.try_recv(), Ok(None));
        assert!(!tx.is_canceled());
        assert!(tx.send(42).is_ok());
        assert_eq!(rx.try_recv(), Ok(Some(42)));
    }

    // 2. oneshot::channel signals Canceled when Sender is dropped without sending
    {
        let (tx, mut rx) = oneshot::channel::<i32>();
        drop(tx);
        assert_eq!(rx.try_recv(), Err(oneshot::Canceled));
    }

    // 3. oneshot::Receiver::close marks channel complete and Sender is_canceled returns true
    {
        let (tx, mut rx) = oneshot::channel::<i32>();
        rx.close();
        assert!(tx.is_canceled());
        assert_eq!(tx.send(100), Err(100));
    }

    // 4. mpsc::unbounded transmits multiple values in FIFO order via unbounded_send and try_recv
    {
        let (tx, mut rx) = mpsc::unbounded::<&'static str>();
        assert!(tx.unbounded_send("first").is_ok());
        assert!(tx.unbounded_send("second").is_ok());
        assert_eq!(rx.try_recv(), Ok("first"));
        assert_eq!(rx.try_recv(), Ok("second"));
        assert_eq!(rx.try_recv(), Err(TryRecvError::Empty));
    }

    // 5. mpsc::channel with capacity limit returns TrySendError full when buffer is exhausted
    {
        let (mut tx, mut rx) = mpsc::channel::<u32>(1);
        assert!(tx.try_send(10).is_ok());
        assert!(tx.try_send(20).is_ok());
        let send_err = tx.try_send(30).unwrap_err();
        assert!(send_err.is_full());
        assert_eq!(send_err.into_inner(), 30);
        assert_eq!(rx.try_recv(), Ok(10));
        assert_eq!(rx.try_recv(), Ok(20));
        assert_eq!(rx.try_recv(), Err(TryRecvError::Empty));
    }

    // 6. mpsc::Receiver::close closes the channel causing subsequent try_send to fail with disconnected
    {
        let (mut tx, mut rx) = mpsc::channel::<u32>(1);
        rx.close();
        let err = tx.try_send(99).unwrap_err();
        assert!(err.is_disconnected());
        assert_eq!(rx.try_recv(), Err(TryRecvError::Closed));
    }

    println!("All futures-channel contract assertions passed successfully.");
}