Sample
golang.org/x/sync 0.22.0: CompareAndSwap and CompareAndDelete on syncmap.Map distinguish absent keys from stored nil values rather than treating absent keys as nil
Verified sample for golang golang.org/x/sync 0.22.0: CompareAndSwap and CompareAndDelete on syncmap.Map distinguish absent keys from stored nil values rather…
sha256:bb4cbf8a68f1606db024e32344cb04fd7a29f9c7fb1815eb5b9f5019df273754
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
go linux x64 go go gomod
Verification-run environments
| Environment | Contract | Stages | Run |
|---|---|---|---|
| go 1.26 · linux alpine/x64 · docker ed25519:d91480838ac982c9 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · golang@1 |
2026-08-17 |
| go 1.26 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · golang@1 |
2026-08-18 |
Case
HOW- Goal
- CompareAndSwap and CompareAndDelete on syncmap.Map distinguish absent keys from stored nil values rather than treating absent keys as nil
- Packages
- Symbols
-
- syncmap.Map
- syncmap.Map.CompareAndSwap
- syncmap.Map.CompareAndDelete
- syncmap.Map.Swap
- syncmap.Map.LoadAndDelete
- syncmap.Map.Load
- syncmap.Map.Store
- Environment
- go
- Created
- 2026-08-17T23:39:23Z
Contract
- CompareAndSwap on an absent key returns false when old is nil, but succeeds and returns true when the key was explicitly stored with nil
- CompareAndDelete returns false on absent keys when old is nil, and returns true only when the key was explicitly stored with nil
- Load and LoadAndDelete distinguish absent keys (loaded=false) from keys explicitly stored with nil (loaded=true)
- Swap overwrites any existing value and returns whether the key was previously present
- Passing an unhashable key type such as a slice panics at runtime with hash of unhashable type
- CompareAndDelete and CompareAndSwap panic when comparing against an existing value of identical incomparable slice type, but return false without panic when the stored type differs
Files
- NOTES.md
- csx.json
- go.mod
- go.sum
- syncmap_test.go