Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

rt: fix accidental unsetting of current handle #5178

Merged
merged 2 commits into from
Nov 9, 2022
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 9 additions & 5 deletions tokio/src/runtime/context.rs
Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,7 @@ cfg_rt! {
use std::fmt;

#[derive(Debug, Clone, Copy)]
#[must_use]
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

These annotations would have caught the issue earlier.

pub(crate) enum EnterRuntime {
/// Currently in a runtime context.
#[cfg_attr(not(feature = "rt"), allow(dead_code))]
Expand All @@ -84,17 +85,22 @@ cfg_rt! {
}

#[derive(Debug)]
#[must_use]
pub(crate) struct SetCurrentGuard {
old_handle: Option<scheduler::Handle>,
old_seed: RngSeed,
}

/// Guard tracking that a caller has entered a runtime context.
#[must_use]
pub(crate) struct EnterRuntimeGuard {
pub(crate) blocking: BlockingRegionGuard,
#[allow(dead_code)] // Only tracking the guard.
pub(crate) handle: SetCurrentGuard,
Darksonn marked this conversation as resolved.
Show resolved Hide resolved
}

/// Guard tracking that a caller has entered a blocking region.
#[must_use]
pub(crate) struct BlockingRegionGuard {
_p: PhantomData<RefCell<()>>,
}
Expand All @@ -121,10 +127,7 @@ cfg_rt! {
/// executor.
#[track_caller]
pub(crate) fn enter_runtime(handle: &scheduler::Handle, allow_block_in_place: bool) -> EnterRuntimeGuard {
if let Some(enter) = try_enter_runtime(allow_block_in_place) {
// Set the current runtime handle. This should not fail. A later
// cleanup will remove the unwrap().
try_set_current(handle).unwrap();
if let Some(enter) = try_enter_runtime(handle, allow_block_in_place) {
return enter;
}

Expand All @@ -138,14 +141,15 @@ cfg_rt! {

/// Tries to enter a runtime context, returns `None` if already in a runtime
/// context.
fn try_enter_runtime(allow_block_in_place: bool) -> Option<EnterRuntimeGuard> {
fn try_enter_runtime(handle: &scheduler::Handle, allow_block_in_place: bool) -> Option<EnterRuntimeGuard> {
CONTEXT.with(|c| {
if c.runtime.get().is_entered() {
None
} else {
c.runtime.set(EnterRuntime::Entered { allow_block_in_place });
Some(EnterRuntimeGuard {
blocking: BlockingRegionGuard::new(),
handle: c.set_current(handle),
})
}
})
Expand Down
33 changes: 25 additions & 8 deletions tokio/tests/rt_common.rs
Original file line number Diff line number Diff line change
Expand Up @@ -243,14 +243,6 @@ rt_test! {
tokio::spawn(async move {
let (done_tx, mut done_rx) = mpsc::unbounded_channel();

/*
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Happened to find this, so deleted.

for _ in 0..100 {
tokio::spawn(async move { });
}

tokio::task::yield_now().await;
*/

let mut txs = (0..ITER)
.map(|i| {
let (tx, rx) = oneshot::channel();
Expand Down Expand Up @@ -291,6 +283,31 @@ rt_test! {
}
}

#[test]
fn spawn_one_from_block_on_called_on_handle() {
let rt = rt();
let (tx, rx) = oneshot::channel();

#[allow(clippy::async_yields_async)]
let handle = rt.handle().block_on(async {
tokio::spawn(async move {
tx.send("ZOMG").unwrap();
"DONE"
})
});

let out = rt.block_on(async {
let msg = assert_ok!(rx.await);

let out = assert_ok!(handle.await);
assert_eq!(out, "DONE");

msg
});

assert_eq!(out, "ZOMG");
}

#[test]
fn spawn_await_chain() {
let rt = rt();
Expand Down