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fix(runtime): root raw-pointer windows across user callbacks (sort, stringify, replace, BigInt64 sort, matchAll) #6191

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Merged
proggeramlug merged 1 commit into from
Jul 9, 2026
Merged

fix(runtime): root raw-pointer windows across user callbacks (sort, stringify, replace, BigInt64 sort, matchAll) #6191

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37 changes: 21 additions & 16 deletions crates/perry-runtime/src/array/generic.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1541,39 +1541,44 @@ pub(crate) fn object_sort(recv: f64, cmp_validated: *const ClosureHeader) -> f64
};
let len = al_length(recv);
unsafe {
// Rooted temp array: keeps accessor-produced values alive across
// comparator calls (a Rust Vec would be invisible to the GC scan).
let temp = js_array_alloc_with_length(len.clamp(0, u32::MAX as i64) as u32);
let temp_elems = (temp as *mut u8).add(std::mem::size_of::<ArrayHeader>()) as *mut f64;
// Root BOTH the receiver value and the collection temp for the whole
// protocol: `al_has`/`al_get`/`al_set` fire user accessors (and the
// comparator runs inside `sort_rooted_values`) — any of them can
// allocate and sweep or move either object, so every raw pointer is
// re-derived from its rooted handle after each such call.
let scope = crate::gc::RuntimeHandleScope::new();
let recv_handle = scope.root_nanbox_f64(recv);
Comment on lines 1542 to +1550

@coderabbitai coderabbitai Bot Jul 9, 2026

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🩺 Stability & Availability | 🟠 Major | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
rg -nP --type=rust -C3 '\bfn al_length\b' crates/perry-runtime/src/array/generic.rs
rg -nP --type=rust -C4 '\bobject_sort\s*\(' crates/perry-runtime/src/array

Repository: PerryTS/perry

Length of output: 4470

🏁 Script executed:

sed -n '260,340p' crates/perry-runtime/src/array/generic.rs
printf '\n---\n'
sed -n '1536,1575p' crates/perry-runtime/src/array/generic.rs
printf '\n---\n'
sed -n '520,560p' crates/perry-runtime/src/array/sort.rs
printf '\n---\n'
sed -n '630,660p' crates/perry-runtime/src/array/sort.rs

Repository: PerryTS/perry

Length of output: 9530

🏁 Script executed:

sed -n '1,120p' crates/perry-runtime/src/array/sort.rs
printf '\n---\n'
rg -nP --type=rust -C3 '\bnon_array_object_receiver\b' crates/perry-runtime/src

Repository: PerryTS/perry

Length of output: 8521

Root recv before al_length in object_sort

al_length(recv) can run user code for object receivers (length accessors/proxy get) and can also allocate the "length" key string. js_array_sort_default and js_array_sort_with_comparator pass a raw receiver into object_sort, so root it before the length read; rooting afterward leaves a moving-GC window.

🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/perry-runtime/src/array/generic.rs` around lines 1542 - 1550, In
object_sort, root the receiver before calling al_length(recv) because that
length lookup can invoke user code and allocate, leaving a GC/moving-window if
recv is still raw. Move the RuntimeHandleScope creation and recv_handle rooting
ahead of the length read, and keep using the rooted handle consistently in
js_array_sort_default and js_array_sort_with_comparator paths where object_sort
is entered.

let temp = super::sort::RootedArrayElems::new(
&scope,
js_array_alloc_with_length(len.clamp(0, u32::MAX as i64) as u32),
);
let mut count = 0usize;
let mut undef_count = 0usize;
for j in 0..len {
if al_has(recv, j) {
let v = al_get(recv, j);
if al_has(recv_handle.get_nanbox_f64(), j) {
let v = al_get(recv_handle.get_nanbox_f64(), j);
if v.to_bits() == TAG_UNDEFINED {
undef_count += 1;
} else {
// GC_STORE_AUDIT(BARRIERED): temp collection array rebuilt below.
ptr::write(temp_elems.add(count), v);
temp.set(count, v);
count += 1;
}
}
}
(*temp).length = count as u32;
rebuild_array_layout(temp);
super::sort::sort_rooted_values(temp_elems, count, cmp);
rebuild_array_layout(temp);
(*temp.arr()).length = count as u32;
rebuild_array_layout(temp.arr());
let _ = super::sort::sort_rooted_values(temp.arr(), count, cmp);
for j in 0..count {
al_set(recv, j as i64, *temp_elems.add(j));
al_set(recv_handle.get_nanbox_f64(), j as i64, temp.get(j));
}
for j in count..count + undef_count {
al_set(recv, j as i64, undef());
al_set(recv_handle.get_nanbox_f64(), j as i64, undef());
}
for j in (count + undef_count) as i64..len {
al_delete(recv, j);
al_delete(recv_handle.get_nanbox_f64(), j);
}
recv_handle.get_nanbox_f64()
}
recv
}

/// `Array.prototype.concat` over a non-real-array receiver: the receiver is
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