func getInnerKV(err error) KV {
kvi := errctx.Get(err, errKV)
if kvi == nil {
return KV{}
}
return kvi.(KV)
}
// ErrWithKV embeds a KV into an error, returning a new error instance. If the
// error already has a KV embedded in it then the returned error will have a
// the merging of the two.
func ErrWithKV(err error, kv KV) error {
if err == nil {
return nil
}
existingKV := errctx.Get(err, errKV)
if existingKV != nil {
kv = Merge(existingKV.(KV), kv)
}
return errctx.Set(err, errKV, kv)
}