What changed in Go, Rust and Solidity this week.

// This example demonstrates the new std::io::pipe API.
// It does not compile on Rust 1.98.1 because io::pipe was added in 1.87.0.
// To run it, use rustc 1.87.0 or later.

use std::io::{self, Read};
use std::process::Command;

fn main() -> io::Result<()> {
    // Create an anonymous pipe.
    let (mut reader, writer) = io::pipe()?;

    // Spawn a child process that writes to both stdout and stderr.
    let mut child = Command::new("sh")
        .arg("-c")
        .arg("echo out; echo err 1>&2")
        .stdout(writer.try_clone()?) // send stdout to the pipe
        .stderr(writer)              // send stderr to the pipe
        .spawn()?;

    // Read all output from the pipe.
    let mut output = Vec::new();
    reader.read_to_end(&mut output)?;

    // Wait for the child to finish.
    child.wait()?;

    // Print what we captured.
    println!("Captured output:\n{}", String::from_utf8_lossy(&output));
    Ok(())
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.37;

// This contract demonstrates that delete on a memory bytes array element
// clears only the targeted byte, not the whole 32‑byte word.
contract Main {
    function clearByte(uint index) external pure returns (bytes memory) {
        bytes memory data = new bytes(5);
        // set all bytes to 0xFF for visibility
        for (uint i = 0; i < data.length; i++) {
            data[i] = 0xFF;
        }
        // delete the element at `index`
        delete data[index];
        return data;
    }
}

Tests

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.37;

import "./main.sol";

contract MainTest {
    Main main;

    constructor() {
        main = new Main();
    }

    function test_singleByteCleared() public {
        bytes memory result = main.clearByte(2);
        // bytes[2] should be 0x00, others remain 0xFF
        require(result[2] == 0x00, "byte not cleared");
        require(result[0] == 0xFF, "other byte altered");
        require(result[1] == 0xFF, "other byte altered");
        require(result[3] == 0xFF, "other byte altered");
        require(result[4] == 0xFF, "other byte altered");
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.37;

// This contract demonstrates the 0.8.37 delete‑byte‑array‑element fix.
// It creates a memory bytes array, sets each element to 0x01,
// deletes the middle element, and returns the array.
contract Demo {
    function deleteMiddle() external pure returns (bytes memory) {
        bytes memory b = new bytes(3);
        b[0] = 0x01;
        b[1] = 0x01;
        b[2] = 0x01;
        delete b[1]; // only b[1] should become 0x00
        return b;
    }
}

Tests

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.37;
import "./main.sol";

contract DemoTest {
    Demo demo;

    constructor() {
        demo = new Demo();
    }

    function test_deleteLeavesOtherBytes() external {
        bytes memory result = demo.deleteMiddle();
        require(result.length == 3, "wrong length");
        require(result[0] == 0x01, "b[0] altered");
        require(result[1] == 0x00, "b[1] not zeroed");
        require(result[2] == 0x01, "b[2] altered");
    }
}