Sample
serde 1.0.229: Flattening an Option<T> field with serde silently instantiates Some(T) with all None fields when input keys are completely missing instead of evaluating to None
Verified sample for cargo serde 1.0.229: Flattening an Option<T> field with serde silently instantiates Some(T) with all None fields when input keys are…
sha256:586fa2d13da8d07f8cba0752874e0d457509e3eb71c5c9f174986d8f12e9fb0b
This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured.
How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people.
MIT-0
Execution evidence
The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.
- Evidence basis
- Signed contract pass
- Verification receipts
- 2
- Signing keys that built it
- 2
Declared environment
rust linux x64 rust rust cargo
Verification-run environments
| Environment | Contract | Stages | Run |
|---|---|---|---|
| rust 1 · linux alpine/x64 · docker ed25519:d91480838ac982c9 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · cargo@1 |
2026-08-17 |
| rust 1 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · cargo@1 |
2026-08-18 |
Case
HOW- Goal
- Flattening an Option<T> field with serde silently instantiates Some(T) with all None fields when input keys are completely missing instead of evaluating to None
- Packages
- Symbols
-
- serde::Deserialize
- Environment
- rust
- Created
- 2026-08-17T02:34:45Z
Contract
- Deserializing into Option<T> via #[serde(flatten)] where T has all Option fields returns Some(T) with None fields even when no relevant keys are present in JSON
- Deserializing into Option<T> via #[serde(flatten)] where T has required fields without defaults fails inner parsing and returns None when keys are missing
- Branching logic relying on if let Some(...) on flattened Option structs silently executes unexpectedly when inner fields are optional
Files
- .gitignore
- Cargo.lock
- Cargo.toml
- NOTES.md
- csx.json
- src/lib.rs