fish2018/pansou · error
PoW验证数据无效: x
Error message
PoW验证数据无效: x
What it means
computePowResult parses the challenge base x from hex via big.Int.SetString and requires it to be a non-negative integer. This error is returned when challenge.X is empty, not valid hex, or parses to a negative number, so the repeated-squaring y = x^(2^t) mod N cannot proceed.
Solutions
- Log challenge.X and the raw challenge response to see the actual value format
- Re-fetch a fresh challenge; truncated/corrupted bodies are the typical cause
- If the value is decimal or prefixed (0x), convert/strip before SetString(X, 16)
- Pre-validate X client-side: non-empty hex, parses, value >= 0
Example fix
// before
y, ok := new(big.Int).SetString(challenge.X, 16)
// after
xHex := strings.TrimPrefix(strings.ToLower(challenge.X), "0x")
y, ok := new(big.Int).SetString(xHex, 16)
if !ok || y.Sign() < 0 {
return "", fmt.Errorf("PoW验证数据无效: x")
} Defensive patterns
Strategy: validation
Validate before calling
func validHexNonNegative(s string) bool {
x, ok := new(big.Int).SetString(strings.TrimPrefix(s, "0x"), 16)
return ok && x.Sign() >= 0
}
if !validHexNonNegative(ch.X) { /* re-fetch challenge before solving */ } Type guard
func isValidPowBase(c *ChallengePageData) bool {
x, ok := new(big.Int).SetString(c.X, 16)
return ok && x != nil && x.Sign() >= 0
} Try / catch
y, err := p.computePowResult(challenge)
if err != nil {
if strings.Contains(err.Error(), ": x") {
return p.refetchAndSolve(scraper, requestURL)
}
return err
} Prevention
- Inspect the challenge JSON when a solver error occurs — base encoding changes (hex vs decimal) are common upstream drift
- Strip optional 0x prefixes and lowercase hex before SetString
- Validate all PoW fields (N, X, T) in one place after parsing the challenge
When it happens
Trigger: computePowResult is called with a ChallengePageData whose X field fails hex parsing or yields y.Sign() < 0 (e.g. X="", X="zz", or X="-a1").
Common situations: Upstream changed the challenge JSON so the base is now decimal or base64-encoded instead of hex; the challenge body was truncated in transit; test fixtures with placeholder values are fed to the solver.
Understand the failure class
Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.
Related errors
AI-assisted analysis of fish2018/pansou@beaa561337 (2026-09-07).
Data as JSON: /api/errors/8c1c33fee9e37d85.
Report an issue: GitHub.
Appendix: source
Thrown at plugin/gying/gying.go:1745
}
form := url.Values{}
form.Set("action", "verify")
form.Set("id", challenge.ID)
form.Set("y", y)
return p.submitChallengeVerification(scraper, requestURL, form)
}
func (p *GyingPlugin) computePowResult(challenge *ChallengePageData) (string, error) {
modulus, ok := new(big.Int).SetString(challenge.N, 16)
if !ok || modulus.Sign() <= 0 {
return "", fmt.Errorf("PoW验证数据无效: N")
}
y, ok := new(big.Int).SetString(challenge.X, 16)
if !ok || y.Sign() < 0 {
return "", fmt.Errorf("PoW验证数据无效: x")
}
if challenge.T <= 0 {
return "", fmt.Errorf("PoW验证数据无效: t")
}
if DebugLog {
fmt.Printf("[Gying] PoW Challenge计算开始: id=%s t=%d nBits=%d\n",
challenge.ID, challenge.T, modulus.BitLen())
}
start := time.Now()
for i := 0; i < challenge.T; i++ {
y.Mul(y, y)
y.Mod(y, modulus)
}
elapsed := time.Since(start)
if DebugLog {View on GitHub (pinned to beaa561337)