What causes "unknown validation error" in chenhg5/cc-connect?

Re-run with --debug if available to see which base URLs were attempted.

unknown validation error

Error message

unknown validation error

What it means

validateAppCredentials falls back to "unknown validation error" when the candidate loop ends with lastErr == nil, i.e. no candidate produced a definitive success or failure. This is a defensive placeholder indicating the validation loop never actually attempted a check.

Source

Thrown at cmd/cc-connect/feishu.go:493

	var lastErr error
	for _, candidate := range candidates {
		base := openFeishuBaseURL
		if candidate == "lark" {
			base = openLarkBaseURL
		}
		ok, err := validateAppCredentialsAgainstBase(base, appID, appSecret)
		if err != nil {
			lastErr = err
			continue
		}
		if ok {
			return candidate, nil
		}
		lastErr = fmt.Errorf("remote returned non-zero code")
	}
	if lastErr == nil {
		lastErr = fmt.Errorf("unknown validation error")
	}
	return "", lastErr
}

func validateAppCredentialsAgainstBase(baseURL, appID, appSecret string) (bool, error) {
	body, _ := json.Marshal(map[string]string{
		"app_id":     appID,
		"app_secret": appSecret,
	})
	req, err := http.NewRequest(http.MethodPost, baseURL+"/open-apis/auth/v3/tenant_access_token/internal", bytes.NewReader(body))
	if err != nil {
		return false, err
	}
	req.Header.Set("Content-Type", "application/json")

	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {

View on GitHub (pinned to 4000b2338a)

Solutions

Re-run with --debug if available to see which base URLs were attempted.
Explicitly pass --platform-type feishu or lark so a valid candidate base URL is generated.
Check network/proxy settings; if requests fail before producing an error the loop may never set lastErr.
If reproducible, report as a bug — this message signals an unhandled path in validateAppCredentials.

Defensive patterns

Strategy: fallback

Validate before calling

if platformType == "" { platformType = "feishu" } // ensure a candidate base URL exists before validation

Try / catch

if err != nil && strings.Contains(err.Error(), "unknown validation error") { log.Printf("validation loop produced no attempt; re-run with explicit --platform-type and debug enabled") }

Prevention

Always set --platform-type explicitly so at least one base URL candidate is generated.
Use --debug to observe which validation attempts ran.
Report persistent occurrences as a bug in candidate generation.

When it happens

Trigger: The candidate base URL list was empty, or every iteration hit the `continue` path without setting lastErr (an edge case in how candidates/errors are collected), leaving lastErr nil after the loop.

Common situations: Misconfigured or empty platform-type/base-URL candidate derivation; an internal edge case rather than a user-input mistake.

Understand the failure class

Background: "invalid response format", "malformed payload", "missing data field": when an API returns 200 but the response shape is wrong — this error's family across 23 libraries.

Related errors

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/9277fbd74db49946. Report an issue: GitHub.