Sample
Prove once_cell fallible initialization retry semantics, non-poisoning error recovery, unsync reentrancy panic behavior, and cell lifecycle reset
sha256:e0afb4151238134f23cb7f9babe65162ab344625d8c386e357c4dafa43f92775
PUBLISHED
L3_CONTRACT_PASS
MIT-0
Execution evidence
Declared environment and signed verification runs are separated so you can see exactly what this sample proves.
Evidence basisSigned contract pass
Verification receipts1
Verification levelL3_CONTRACT_PASS
Declared environment
- Execution context
- rust
- Operating system
- linux
- Architecture
- x64
- Runtime
- rust
- Language
- rust
- Package manager
- cargo
Verification-run environments
- Execution context
- rust 1
- Operating system
- linux alpine · musl
- Architecture
- x64
- Runtime
- rust 1
- Language
- rust
- Package manager
- cargo
- Execution
- container · docker
CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · cargo@1 · 2026-08-17
Case
- Goal
- Prove once_cell fallible initialization retry semantics, non-poisoning error recovery, unsync reentrancy panic behavior, and cell lifecycle reset HOW
- Packages
-
once_cell 1.21.4
- Environment
- rust
- Created
- 2026-08-17T20:42:35Z
Commonly assumed
A common belief is that OnceCell initialization failure permanently poisons the cell preventing subsequent retry, or that unsync::OnceCell allows recursive initialization without panicking.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- get_or_try_init leaves the OnceCell uninitialized upon receiving Err, enabling subsequent initialization attempts to retry and succeed without cell poisoning
- sync::OnceCell coordinates concurrent fallible initializers such that a failing thread unblocks waiting threads to retry and initialize the value
- unsync::OnceCell safely returns None for get() during initialization but panics with reentrant init when get_or_init or set is called reentrantly
- unsync::OnceCell cleanly resets its state upon panic unwind, allowing subsequent get_or_init invocations to initialize the cell
- OnceCell structural equality evaluates uninitialized cells as equal and take resets an initialized cell back to empty state for re-initialization
Files
- Cargo.lock
- Cargo.toml
- NOTES.md
- csx.json
- src/lib.rs
Download the source artifact (tar.gz)
Origin Seeder
csx-seed
Verification receipts
- rust 1 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · cargo@1 · 2026-08-17 · ed25519:d91480838ac982c9