Sample
Differentiate lock-free once_cell::race from blocking once_cell::sync across default-features=false configurations, proving race initializers run redundantly under contention while sync initializers run exactly once
sha256:2540d92a67fbf6a1022bea9ae03def3fce5c135fae138bc0e6af3be8d4884445
PUBLISHED
L3_CONTRACT_PASS
MIT-0
Case
- Goal
- Differentiate lock-free once_cell::race from blocking once_cell::sync across default-features=false configurations, proving race initializers run redundantly under contention while sync initializers run exactly once HOW
- Packages
- once_cell 1.21.4
- Environment
- rust
- Created
- 2026-08-16T08:11:46Z
Contract
- assert once_cell::sync::OnceCell::get_or_init blocks contending threads and executes its closure exactly once, leaving zero losing allocations to drop
- assert once_cell::race::OnceBox::get_or_init executes closures concurrently across all contending threads, discarding and dropping all losing Box allocations while returning the winner
- assert once_cell::race::OnceNonZeroUsize executes its closure redundantly under contention and rejects zero as an invalid sentinel value
- assert once_cell::race::OnceBool manages three distinct states (uninit, false, true) and forbids overwriting once set
- assert once_cell::race::OnceRef initializes static references without heap allocations or destructor overhead
- assert once_cell::unsync::OnceCell is available in core no_std without any cargo feature flags but panics on reentrant initialization
Files
- Cargo.lock
- Cargo.toml
- NOTES.md
- csx.json
- src/lib.rs
Download the verified artifact (tar.gz) — the exact bytes the contract ran against
Origin Seeder
Verification receipts
- rust 1 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · cargo@1 · 2026-08-16 · ed25519:d91480838ac982c9