lean_string 0.7.0

// MIRIFLAGS="-Zmiri-preemption-rate=1" cargo +nightly miri test --test race_condition
//
// These tests target use-after-free races in CoW uniqueness checks. Loom cannot detect these
// because they are UB (not logic errors). Miri with preemption is the right tool: it explores
// thread interleavings and flags reads/writes to deallocated memory.

use lean_string::{LeanStr, LeanString};
use std::thread;

#[test]
fn drop_while_push() {
    let mut one = LeanString::from("12345678901234567890");
    let two = one.clone();

    let th = thread::spawn(move || {
        drop(two);
    });

    one.push('a');
    assert_eq!(one, "12345678901234567890a");

    th.join().unwrap();
}

#[test]
fn drop_while_remove() {
    let mut one = LeanString::from("abcdefghijklmnopqrstuvwxyz");
    let two = one.clone();

    let th = thread::spawn(move || {
        drop(two);
    });

    assert_eq!(one.remove(0), 'a');
    assert_eq!(one, "bcdefghijklmnopqrstuvwxyz");

    th.join().unwrap();
}

#[test]
fn drop_while_retain() {
    let mut one = LeanString::from("abcdefghijklmnopqrstuvwxyz");
    let two = one.clone();

    let th = thread::spawn(move || {
        drop(two);
    });

    one.retain(|c| c != 'a');
    assert_eq!(one, "bcdefghijklmnopqrstuvwxyz");

    th.join().unwrap();
}

#[test]
fn drop_while_truncate() {
    let mut one = LeanString::from("abcdefghijklmnopqrstuvwxyz");
    let two = one.clone();

    let th = thread::spawn(move || {
        drop(two);
    });

    one.truncate(10);
    assert_eq!(one, "abcdefghij");

    th.join().unwrap();
}

#[test]
fn drop_lean_str_while_mutating_lean_string() {
    let one = LeanStr::from("abcdefghijklmnopqrstuvwxyz");
    let two = one.clone();

    let th = thread::spawn(move || {
        drop(two);
    });

    let mut one_p = one.into_lean_string();
    one_p.push('!');
    assert_eq!(one_p, "abcdefghijklmnopqrstuvwxyz!");

    th.join().unwrap();
}

#[test]
fn drop_lean_string_while_into_lean_str() {
    let mut string = LeanString::with_capacity(128);
    string.push_str("abcdefghijklmnopqrstuvwxyz");
    let shared = string.clone();

    let th = thread::spawn(move || {
        drop(shared);
    });

    let frozen = string.into_lean_str();
    assert_eq!(frozen, "abcdefghijklmnopqrstuvwxyz");

    th.join().unwrap();
}