Errors

Failing operations return *nono.Error. Use errors.Is with the exported sentinel errors when you need to branch on the failure kind.

err := caps.AllowPath("/missing", nono.AccessRead)
if errors.Is(err, nono.ErrPathNotFound) {
	log.Println("path does not exist")
}

Use errors.As when you need the numeric code or human-readable message from the native library.

var nonoErr *nono.Error
if errors.As(err, &nonoErr) {
	log.Println(nonoErr.Code(), nonoErr.Message())
}

Sentinel errors

Sentinel	Meaning
`nono.ErrPathNotFound`	The path does not exist
`nono.ErrExpectedDirectory`	A directory was required
`nono.ErrExpectedFile`	A file was required
`nono.ErrPathCanonicalization`	Path canonicalization failed
`nono.ErrNoCapabilities`	No capabilities were configured
`nono.ErrSandboxInit`	Platform sandbox initialization failed
`nono.ErrUnsupportedPlatform`	Sandboxing is unavailable on this platform
`nono.ErrBlockedCommand`	A command was blocked by policy
`nono.ErrConfigParse`	Configuration parsing failed
`nono.ErrProfileParse`	Profile parsing failed
`nono.ErrIO`	An I/O operation failed
`nono.ErrInvalidArg`	An invalid argument was passed
`nono.ErrTrustVerification`	Trust verification failed
`nono.ErrUnknown`	Unknown or uncategorized failure

nono.Error.Is matches by error code, so the native message does not need to match the sentinel’s message.