CodeSampleX

Sample

Configure custom random reader for UUIDv4 generation and restore default entropy source with github.com/google/uuid.SetRand

sha256:70972c336b0e3d20a42390c23c2228a9bb9729ac19ccea053c5675b289c6341b

Publication state. LOCAL_PASS passed only on its author's machine; PUBLISHED is public and awaiting independent verification; CROSS_PASS was reproduced by another verifier; MATRIX_PASS passed across environment boundaries; STABLE has sustained independent passes without recent failures. Evidence strength. L0 is source only; L1 resolved dependencies; L2 compiled or loaded; L3 passed its contract; L4 was independently reproduced; L5 passed across different environments. MIT-0

Execution evidence

Declared environment and signed verification runs are separated so you can see exactly what this sample proves.

Evidence basis
Independent cross-verification
Verification receipts
1
Verification level
L4_CROSS_PASS
Declared environment linux 24 · ubuntu · glibc 2.39 x64 go wsl

Verification-run environments

Environment Contract Stages Run
go 1.26 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · golang@1
2026-08-19

Case

HOW
Goal
Configure custom random reader for UUIDv4 generation and restore default entropy source with github.com/google/uuid.SetRand
Packages
Symbols
  • github.com/google/uuid.SetRand
Created
2026-08-19T09:46:00Z

Contract

  1. uuid.SetRand with a custom io.Reader overrides entropy source for uuid.New and uuid.NewRandom to produce deterministic UUID bytes with version 4 and RFC4122 variant
  2. uuid.SetRand with nil restores default crypto/rand entropy source generating valid Version 4 RFC4122 UUIDs
  3. uuid.SetRand with an error-returning reader causes a panic when generating random UUIDs
  4. UUIDs generated with custom and default rand sources format as valid 36-character hyphenated UUID strings and round-trip via uuid.Parse

Files

  • PROMPT.md
  • csx.json
  • go.mod
  • go.sum
  • main.go
  • spec.json
  • test/contract.go

Download the source artifact (tar.gz)

Origin Seeder

anonymous