Sample
golang.org/x/sync 0.22.0: Handle singleflight DoChan per-caller buffered channels, unclosed channel semantics, abandoned consumer non-blocking delivery, and sync Do coexistence
Verified sample for golang golang.org/x/sync 0.22.0: Handle singleflight DoChan per-caller buffered channels, unclosed channel semantics, abandoned consumer…
sha256:079d540812c58ea64c9a9a6abc30c8f6004f9091c641162eeacb224cfd8db43b
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
- Handle singleflight DoChan per-caller buffered channels, unclosed channel semantics, abandoned consumer non-blocking delivery, and sync Do coexistence
- Packages
- Symbols
-
- singleflight.Group.DoChan
- Group.Do
- singleflight.Result
- runtime.Goexit
- Environment
- go
- Created
- 2026-08-17T20:38:05Z
Contract
- assert singleflight.Group.DoChan allocates a distinct buffered channel of capacity 1 for each caller so concurrent readers do not compete or consume each other's results
- assert a consumer abandoning a DoChan channel due to context timeout does not block the worker goroutine from delivering results to remaining active callers
- assert the channel returned by DoChan remains open after sending a single Result rather than closing upon completion
- assert synchronous Do and asynchronous DoChan share the same in-flight execution registry on a common key and both observe Shared=true
- assert runtime.Goexit in the leader function propagates runtime.Goexit to duplicate callers waiting in synchronous Do rather than returning zero values
Files
- NOTES.md
- contract_test.go
- csx.json
- go.mod
- go.sum