chore: add vendor dependencies for kauma build

vendor/once_cell/tests/it/unsync_once_cell.rs

@@ -0,0 +1,154 @@
+use core::{
+    cell::Cell,
+    sync::atomic::{AtomicUsize, Ordering::SeqCst},
+};
+
+use once_cell::unsync::OnceCell;
+
+#[test]
+fn once_cell() {
+    let c = OnceCell::new();
+    assert!(c.get().is_none());
+    c.get_or_init(|| 92);
+    assert_eq!(c.get(), Some(&92));
+
+    c.get_or_init(|| panic!("Kabom!"));
+    assert_eq!(c.get(), Some(&92));
+}
+
+#[test]
+fn once_cell_with_value() {
+    const CELL: OnceCell<i32> = OnceCell::with_value(12);
+    let cell = CELL;
+    assert_eq!(cell.get(), Some(&12));
+}
+
+#[test]
+fn once_cell_get_mut() {
+    let mut c = OnceCell::new();
+    assert!(c.get_mut().is_none());
+    c.set(90).unwrap();
+    *c.get_mut().unwrap() += 2;
+    assert_eq!(c.get_mut(), Some(&mut 92));
+}
+
+#[test]
+fn once_cell_drop() {
+    static DROP_CNT: AtomicUsize = AtomicUsize::new(0);
+    struct Dropper;
+    impl Drop for Dropper {
+        fn drop(&mut self) {
+            DROP_CNT.fetch_add(1, SeqCst);
+        }
+    }
+
+    let x = OnceCell::new();
+    x.get_or_init(|| Dropper);
+    assert_eq!(DROP_CNT.load(SeqCst), 0);
+    drop(x);
+    assert_eq!(DROP_CNT.load(SeqCst), 1);
+}
+
+#[test]
+fn once_cell_drop_empty() {
+    let x = OnceCell::<String>::new();
+    drop(x);
+}
+
+#[test]
+fn clone() {
+    let s = OnceCell::new();
+    let c = s.clone();
+    assert!(c.get().is_none());
+
+    s.set("hello".to_string()).unwrap();
+    let c = s.clone();
+    assert_eq!(c.get().map(String::as_str), Some("hello"));
+}
+
+#[test]
+fn get_or_try_init() {
+    let cell: OnceCell<String> = OnceCell::new();
+    assert!(cell.get().is_none());
+
+    let res = std::panic::catch_unwind(|| cell.get_or_try_init(|| -> Result<_, ()> { panic!() }));
+    assert!(res.is_err());
+    assert!(cell.get().is_none());
+
+    assert_eq!(cell.get_or_try_init(|| Err(())), Err(()));
+
+    assert_eq!(cell.get_or_try_init(|| Ok::<_, ()>("hello".to_string())), Ok(&"hello".to_string()));
+    assert_eq!(cell.get(), Some(&"hello".to_string()));
+}
+
+#[test]
+fn from_impl() {
+    assert_eq!(OnceCell::from("value").get(), Some(&"value"));
+    assert_ne!(OnceCell::from("foo").get(), Some(&"bar"));
+}
+
+#[test]
+fn partialeq_impl() {
+    assert!(OnceCell::from("value") == OnceCell::from("value"));
+    assert!(OnceCell::from("foo") != OnceCell::from("bar"));
+
+    assert!(OnceCell::<String>::new() == OnceCell::new());
+    assert!(OnceCell::<String>::new() != OnceCell::from("value".to_owned()));
+}
+
+#[test]
+fn into_inner() {
+    let cell: OnceCell<String> = OnceCell::new();
+    assert_eq!(cell.into_inner(), None);
+    let cell = OnceCell::new();
+    cell.set("hello".to_string()).unwrap();
+    assert_eq!(cell.into_inner(), Some("hello".to_string()));
+}
+
+#[test]
+fn debug_impl() {
+    let cell = OnceCell::new();
+    assert_eq!(format!("{:#?}", cell), "OnceCell(Uninit)");
+    cell.set(vec!["hello", "world"]).unwrap();
+    assert_eq!(
+        format!("{:#?}", cell),
+        r#"OnceCell(
+    [
+        "hello",
+        "world",
+    ],
+)"#
+    );
+}
+
+#[test]
+#[should_panic(expected = "reentrant init")]
+fn reentrant_init() {
+    let x: OnceCell<Box<i32>> = OnceCell::new();
+    let dangling_ref: Cell<Option<&i32>> = Cell::new(None);
+    x.get_or_init(|| {
+        let r = x.get_or_init(|| Box::new(92));
+        dangling_ref.set(Some(r));
+        Box::new(62)
+    });
+    eprintln!("use after free: {:?}", dangling_ref.get().unwrap());
+}
+
+#[test]
+fn aliasing_in_get() {
+    let x = OnceCell::new();
+    x.set(42).unwrap();
+    let at_x = x.get().unwrap(); // --- (shared) borrow of inner `Option<T>` --+
+    let _ = x.set(27); // <-- temporary (unique) borrow of inner `Option<T>`   |
+    println!("{}", at_x); // <------- up until here ---------------------------+
+}
+
+#[test]
+// https://github.com/rust-lang/rust/issues/34761#issuecomment-256320669
+fn arrrrrrrrrrrrrrrrrrrrrr() {
+    let cell = OnceCell::new();
+    {
+        let s = String::new();
+        cell.set(&s).unwrap();
+    }
+}