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bug: Avoid panic in Backtrace::catpure if query_stack is already mutably borrowed #835

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Merged
MichaReiser merged 1 commit into from
Apr 30, 2025
Merged

bug: Avoid panic in Backtrace::catpure if query_stack is already mutably borrowed #835

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4 changes: 2 additions & 2 deletions src/active_query.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -377,7 +377,7 @@ pub struct Backtrace(Box<[CapturedQuery]>);
impl Backtrace {
pub fn capture() -> Option<Self> {
crate::with_attached_database(|db| {
db.zalsa_local().with_query_stack(|stack| {
db.zalsa_local().try_with_query_stack(|stack| {
Backtrace(
stack
.iter()
Expand All @@ -392,7 +392,7 @@ impl Backtrace {
.collect(),
)
})
})
})?
}
}

Expand Down
47 changes: 32 additions & 15 deletions src/zalsa_local.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -110,15 +110,32 @@ impl ZalsaLocal {
}
}

/// Executes a closure within the context of the current active query stacks.
/// Executes a closure within the context of the current active query stacks (mutable).
#[inline(always)]
pub(crate) fn with_query_stack<R>(
pub(crate) fn with_query_stack_mut<R>(
&self,
c: impl UnwindSafe + FnOnce(&mut QueryStack) -> R,
) -> R {
c(&mut self.query_stack.borrow_mut())
}

#[inline(always)]
pub(crate) fn with_query_stack<R>(&self, c: impl UnwindSafe + FnOnce(&QueryStack) -> R) -> R {
c(&mut self.query_stack.borrow())
}

#[inline(always)]
pub(crate) fn try_with_query_stack<R>(
&self,
c: impl UnwindSafe + FnOnce(&QueryStack) -> R,
) -> Option<R> {
self.query_stack
.try_borrow()
.ok()
.as_ref()
.map(|stack| c(stack))
}

/// Returns the index of the active query along with its *current* durability/changed-at
/// information. As the query continues to execute, naturally, that information may change.
pub(crate) fn active_query(&self) -> Option<(DatabaseKeyIndex, Stamp)> {
Expand All @@ -137,7 +154,7 @@ impl ZalsaLocal {
index: IngredientIndex,
value: A,
) -> Result<(), ()> {
self.with_query_stack(|stack| {
self.with_query_stack_mut(|stack| {
if let Some(top_query) = stack.last_mut() {
top_query.accumulate(index, value);
Ok(())
Expand All @@ -149,7 +166,7 @@ impl ZalsaLocal {

/// Add an output to the current query's list of dependencies
pub(crate) fn add_output(&self, entity: DatabaseKeyIndex) {
self.with_query_stack(|stack| {
self.with_query_stack_mut(|stack| {
if let Some(top_query) = stack.last_mut() {
top_query.add_output(entity)
}
Expand All @@ -158,7 +175,7 @@ impl ZalsaLocal {

/// Check whether `entity` is an output of the currently active query (if any)
pub(crate) fn is_output_of_active_query(&self, entity: DatabaseKeyIndex) -> bool {
self.with_query_stack(|stack| {
self.with_query_stack_mut(|stack| {
if let Some(top_query) = stack.last_mut() {
top_query.is_output(entity)
} else {
Expand All @@ -182,7 +199,7 @@ impl ZalsaLocal {
"report_tracked_read(input={:?}, durability={:?}, changed_at={:?})",
input, durability, changed_at
);
self.with_query_stack(|stack| {
self.with_query_stack_mut(|stack| {
if let Some(top_query) = stack.last_mut() {
top_query.add_read(
input,
Expand All @@ -208,7 +225,7 @@ impl ZalsaLocal {
"report_tracked_read(input={:?}, durability={:?}, changed_at={:?})",
input, durability, changed_at
);
self.with_query_stack(|stack| {
self.with_query_stack_mut(|stack| {
if let Some(top_query) = stack.last_mut() {
top_query.add_read_simple(input, durability, changed_at);
}
Expand All @@ -222,7 +239,7 @@ impl ZalsaLocal {
/// * `current_revision`, the current revision
#[inline(always)]
pub(crate) fn report_untracked_read(&self, current_revision: Revision) {
self.with_query_stack(|stack| {
self.with_query_stack_mut(|stack| {
if let Some(top_query) = stack.last_mut() {
top_query.add_untracked_read(current_revision);
}
Expand All @@ -234,7 +251,7 @@ impl ZalsaLocal {
// FIXME: Use or remove this.
#[allow(dead_code)]
pub(crate) fn report_synthetic_read(&self, durability: Durability, revision: Revision) {
self.with_query_stack(|stack| {
self.with_query_stack_mut(|stack| {
if let Some(top_query) = stack.last_mut() {
top_query.add_synthetic_read(durability, revision);
}
Expand All @@ -253,7 +270,7 @@ impl ZalsaLocal {
/// * the disambiguator index
#[track_caller]
pub(crate) fn disambiguate(&self, key: IdentityHash) -> (Stamp, Disambiguator) {
self.with_query_stack(|stack| {
self.with_query_stack_mut(|stack| {
let top_query = stack.last_mut().expect(
"cannot create a tracked struct disambiguator outside of a tracked function",
);
Expand All @@ -274,7 +291,7 @@ impl ZalsaLocal {

#[track_caller]
pub(crate) fn store_tracked_struct_id(&self, identity: Identity, id: Id) {
self.with_query_stack(|stack| {
self.with_query_stack_mut(|stack| {
let top_query = stack
.last_mut()
.expect("cannot store a tracked struct ID outside of a tracked function");
Expand Down Expand Up @@ -481,7 +498,7 @@ pub(crate) struct ActiveQueryGuard<'me> {
impl ActiveQueryGuard<'_> {
/// Initialize the tracked struct ids with the values from the prior execution.
pub(crate) fn seed_tracked_struct_ids(&self, tracked_struct_ids: &IdentityMap) {
self.local_state.with_query_stack(|stack| {
self.local_state.with_query_stack_mut(|stack| {
#[cfg(debug_assertions)]
assert_eq!(stack.len(), self.push_len);
let frame = stack.last_mut().unwrap();
Expand All @@ -495,7 +512,7 @@ impl ActiveQueryGuard<'_> {
where
I: IntoIterator<Item = DatabaseKeyIndex> + UnwindSafe,
{
self.local_state.with_query_stack(|stack| {
self.local_state.with_query_stack_mut(|stack| {
#[cfg(debug_assertions)]
assert_eq!(stack.len(), self.push_len);
let frame = stack.last_mut().unwrap();
Expand All @@ -508,7 +525,7 @@ impl ActiveQueryGuard<'_> {

/// Invoked when the query has successfully completed execution.
fn complete(self) -> QueryRevisions {
let query = self.local_state.with_query_stack(|stack| {
let query = self.local_state.with_query_stack_mut(|stack| {
stack.pop_into_revisions(
self.database_key_index,
#[cfg(debug_assertions)]
Expand All @@ -530,7 +547,7 @@ impl ActiveQueryGuard<'_> {

impl Drop for ActiveQueryGuard<'_> {
fn drop(&mut self) {
self.local_state.with_query_stack(|stack| {
self.local_state.with_query_stack_mut(|stack| {
stack.pop(
self.database_key_index,
#[cfg(debug_assertions)]
Expand Down