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// Test that values are not leaked in async functions, even in the cases where:
// * Dropping one of the values panics while running the future.
// * The future is dropped at one of its suspend points.
// * Dropping one of the values panics while dropping the future.
//@ run-pass
//@ needs-unwind
//@ edition:2018
#![allow(unused)]
use std::{
cell::{Cell, RefCell},
future::Future,
marker::Unpin,
panic,
pin::Pin,
ptr,
rc::Rc,
task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
};
struct InjectedFailure;
struct Defer<T> {
ready: bool,
value: Option<T>,
}
impl<T: Unpin> Future for Defer<T> {
type Output = T;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
if self.ready {
Poll::Ready(self.value.take().unwrap())
} else {
self.ready = true;
Poll::Pending
}
}
}
/// Allocator tracks the creation and destruction of `Ptr`s.
/// The `failing_op`-th operation will panic.
struct Allocator {
data: RefCell<Vec<bool>>,
failing_op: usize,
cur_ops: Cell<usize>,
}
impl panic::UnwindSafe for Allocator {}
impl panic::RefUnwindSafe for Allocator {}
impl Drop for Allocator {
fn drop(&mut self) {
let data = self.data.borrow();
if data.iter().any(|d| *d) {
panic!("missing free: {:?}", data);
}
}
}
impl Allocator {
fn new(failing_op: usize) -> Self {
Allocator { failing_op, cur_ops: Cell::new(0), data: RefCell::new(vec![]) }
}
fn alloc(&self) -> impl Future<Output = Ptr<'_>> + '_ {
self.fallible_operation();
let mut data = self.data.borrow_mut();
let addr = data.len();
data.push(true);
Defer { ready: false, value: Some(Ptr(addr, self)) }
}
fn fallible_operation(&self) {
self.cur_ops.set(self.cur_ops.get() + 1);
if self.cur_ops.get() == self.failing_op {
panic::panic_any(InjectedFailure);
}
}
}
// Type that tracks whether it was dropped and can panic when it's created or
// destroyed.
struct Ptr<'a>(usize, &'a Allocator);
impl<'a> Drop for Ptr<'a> {
fn drop(&mut self) {
match self.1.data.borrow_mut()[self.0] {
false => panic!("double free at index {:?}", self.0),
ref mut d => *d = false,
}
self.1.fallible_operation();
}
}
async fn dynamic_init(a: Rc<Allocator>, c: bool) {
let _x;
if c {
_x = Some(a.alloc().await);
}
}
async fn dynamic_drop(a: Rc<Allocator>, c: bool) {
let x = a.alloc().await;
if c {
Some(x)
} else {
None
};
}
struct TwoPtrs<'a>(Ptr<'a>, Ptr<'a>);
async fn struct_dynamic_drop(a: Rc<Allocator>, c0: bool, c1: bool, c: bool) {
for i in 0..2 {
let x;
let y;
if (c0 && i == 0) || (c1 && i == 1) {
x = (a.alloc().await, a.alloc().await, a.alloc().await);
y = TwoPtrs(a.alloc().await, a.alloc().await);
if c {
drop(x.1);
a.alloc().await;
drop(y.0);
a.alloc().await;
}
}
}
}
async fn field_assignment(a: Rc<Allocator>, c0: bool) {
let mut x = (TwoPtrs(a.alloc().await, a.alloc().await), a.alloc().await);
x.1 = a.alloc().await;
x.1 = a.alloc().await;
let f = (x.0).0;
a.alloc().await;
if c0 {
(x.0).0 = f;
}
a.alloc().await;
}
async fn assignment(a: Rc<Allocator>, c0: bool, c1: bool) {
let mut _v = a.alloc().await;
let mut _w = a.alloc().await;
if c0 {
drop(_v);
}
_v = _w;
if c1 {
_w = a.alloc().await;
}
}
async fn array_simple(a: Rc<Allocator>) {
let _x = [a.alloc().await, a.alloc().await, a.alloc().await, a.alloc().await];
}
async fn vec_simple(a: Rc<Allocator>) {
let _x = vec![a.alloc().await, a.alloc().await, a.alloc().await, a.alloc().await];
}
async fn mixed_drop_and_nondrop(a: Rc<Allocator>) {
// check that destructor panics handle drop
// and non-drop blocks in the same scope correctly.
//
// Surprisingly enough, this used to not work.
let (x, y, z);
x = a.alloc().await;
y = 5;
z = a.alloc().await;
}
#[allow(unreachable_code)]
async fn vec_unreachable(a: Rc<Allocator>) {
let _x = vec![a.alloc().await, a.alloc().await, a.alloc().await, return];
}
async fn slice_pattern_one_of(a: Rc<Allocator>, i: usize) {
let array = [a.alloc().await, a.alloc().await, a.alloc().await, a.alloc().await];
let _x = match i {
0 => {
let [a, ..] = array;
a
}
1 => {
let [_, a, ..] = array;
a
}
2 => {
let [_, _, a, _] = array;
a
}
3 => {
let [_, _, _, a] = array;
a
}
_ => panic!("unmatched"),
};
a.alloc().await;
}
async fn subslice_pattern_from_end_with_drop(a: Rc<Allocator>, arg: bool, arg2: bool) {
let arr = [a.alloc().await, a.alloc().await, a.alloc().await, a.alloc().await, a.alloc().await];
if arg2 {
drop(arr);
return;
}
if arg {
let [.., _x, _] = arr;
} else {
let [_, _y @ ..] = arr;
}
a.alloc().await;
}
async fn subslice_pattern_reassign(a: Rc<Allocator>) {
let mut ar = [a.alloc().await, a.alloc().await, a.alloc().await];
let [_, _, _x] = ar;
ar = [a.alloc().await, a.alloc().await, a.alloc().await];
let [_, _y @ ..] = ar;
a.alloc().await;
}
async fn move_ref_pattern(a: Rc<Allocator>) {
let mut tup = (a.alloc().await, a.alloc().await, a.alloc().await, a.alloc().await);
let (ref _a, ref mut _b, _c, mut _d) = tup;
a.alloc().await;
}
fn run_test<F, G>(cx: &mut Context<'_>, ref f: F)
where
F: Fn(Rc<Allocator>) -> G,
G: Future<Output = ()>,
{
for polls in 0.. {
// Run without any panics to find which operations happen after the
// penultimate `poll`.
let first_alloc = Rc::new(Allocator::new(usize::MAX));
let mut fut = Box::pin(f(first_alloc.clone()));
let mut ops_before_last_poll = 0;
let mut completed = false;
for _ in 0..polls {
ops_before_last_poll = first_alloc.cur_ops.get();
if let Poll::Ready(()) = fut.as_mut().poll(cx) {
completed = true;
}
}
drop(fut);
// Start at `ops_before_last_poll` so that we will always be able to
// `poll` the expected number of times.
for failing_op in ops_before_last_poll..first_alloc.cur_ops.get() {
let alloc = Rc::new(Allocator::new(failing_op + 1));
let f = &f;
let cx = &mut *cx;
let result = panic::catch_unwind(panic::AssertUnwindSafe(move || {
let mut fut = Box::pin(f(alloc));
for _ in 0..polls {
let _ = fut.as_mut().poll(cx);
}
drop(fut);
}));
match result {
Ok(..) => panic!("test executed more ops on first call"),
Err(e) => {
if e.downcast_ref::<InjectedFailure>().is_none() {
panic::resume_unwind(e);
}
}
}
}
if completed {
break;
}
}
}
fn clone_waker(data: *const ()) -> RawWaker {
RawWaker::new(data, &RawWakerVTable::new(clone_waker, drop, drop, drop))
}
fn main() {
let waker = unsafe { Waker::from_raw(clone_waker(ptr::null())) };
let context = &mut Context::from_waker(&waker);
run_test(context, |a| dynamic_init(a, false));
run_test(context, |a| dynamic_init(a, true));
run_test(context, |a| dynamic_drop(a, false));
run_test(context, |a| dynamic_drop(a, true));
run_test(context, |a| assignment(a, false, false));
run_test(context, |a| assignment(a, false, true));
run_test(context, |a| assignment(a, true, false));
run_test(context, |a| assignment(a, true, true));
run_test(context, |a| array_simple(a));
run_test(context, |a| vec_simple(a));
run_test(context, |a| vec_unreachable(a));
run_test(context, |a| struct_dynamic_drop(a, false, false, false));
run_test(context, |a| struct_dynamic_drop(a, false, false, true));
run_test(context, |a| struct_dynamic_drop(a, false, true, false));
run_test(context, |a| struct_dynamic_drop(a, false, true, true));
run_test(context, |a| struct_dynamic_drop(a, true, false, false));
run_test(context, |a| struct_dynamic_drop(a, true, false, true));
run_test(context, |a| struct_dynamic_drop(a, true, true, false));
run_test(context, |a| struct_dynamic_drop(a, true, true, true));
run_test(context, |a| field_assignment(a, false));
run_test(context, |a| field_assignment(a, true));
run_test(context, |a| mixed_drop_and_nondrop(a));
run_test(context, |a| slice_pattern_one_of(a, 0));
run_test(context, |a| slice_pattern_one_of(a, 1));
run_test(context, |a| slice_pattern_one_of(a, 2));
run_test(context, |a| slice_pattern_one_of(a, 3));
run_test(context, |a| subslice_pattern_from_end_with_drop(a, true, true));
run_test(context, |a| subslice_pattern_from_end_with_drop(a, true, false));
run_test(context, |a| subslice_pattern_from_end_with_drop(a, false, true));
run_test(context, |a| subslice_pattern_from_end_with_drop(a, false, false));
run_test(context, |a| subslice_pattern_reassign(a));
run_test(context, |a| move_ref_pattern(a));
}
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