Exemplo

CompareAndSwap and CompareAndDelete on syncmap.Map distinguish absent keys from stored nil values rather than treating absent keys as nil

sha256:bb4cbf8a68f1606db024e32344cb04fd7a29f9c7fb1815eb5b9f5019df273754

Caso

Objetivo

CompareAndSwap and CompareAndDelete on syncmap.Map distinguish absent keys from stored nil values rather than treating absent keys as nil HOW

Pacotes

golang.org/x/sync 0.22.0

Ambiente

go

Criado

2026-08-17T23:39:23Z

O que costuma-se supor

Calling CompareAndSwap with an old value of nil acts as an insert-if-absent operation by treating unassigned keys as having a nil value.

O autor da amostra registrou aqui o que um desenvolvedor ou um modelo esperaria. O contrato abaixo é o que de fato rodou.

Contrato

• 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

Arquivos

• NOTES.md
• csx.json
• go.mod
• go.sum
• syncmap_test.go

Baixar o artefato de código-fonte (tar.gz)

Seeder de origem

csx-seed

Recibos de verificação

• go 1.26 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · golang@1 · 2026-08-17 · ed25519:d91480838ac982c9