shadow1ng/fscan · error

webscan_program_create_failed

webscan_program_create_failed

Error message

webscan_program_create_failed: %w

What it means

After a successful compile, EvaluateCached builds a runnable program via env.Program(ast, opts...); failure is wrapped as webscan_program_create_failed. This happens when program options (custom functions, optimizations, libraries) conflict with the AST or each other.

Solutions

1. Inspect the wrapped err for which program option failed
2. Check GetBaseProgramOptions for duplicate/conflicting function bindings
3. Ensure every function declared in the env has a matching implementation in options
4. Upgrade/downgrade the cel-go dependency to a compatible version

Example fix

// before (function declared but not bound)
options := []cel.ProgramOption{cel.Functions(...)} // missing cel.CustomTypeProvider etc.
// after (bind the declared function)
options := []cel.ProgramOption{
    cel.Functions(&cel.FunctionOp{Name: "contains", ...}),
}

ast, issues := env.Compile(expr)
if issues.Err() != nil { return issues.Err() }
// option conflicts surface at Program(); smoke-test in CI
if _, err := env.Program(ast, GetBaseProgramOptions()...); err != nil { return err }

result, err := Evaluate(expr, params)
if err != nil {
    if strings.Contains(err.Error(), i18n.GetText("webscan_program_create_failed")) {
        log.Printf("program options mismatch for %q: %v", expr, err)
    }
    return err
}

When it happens

Trigger: Evaluate/EvaluateCached where GetBaseProgramOptions() returns options incompatible with the compiled AST — e.g. a custom function implementation missing, duplicate option registration, or an option failing validation for this expression.

Common situations: Registering the same custom function/library twice in options, a custom function declared in the env but not bound in program options, CEL library version upgrade changing option behavior (deprecated APIs).

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• webscan_cel_env_not_initialized
• webscan_expression_compile_failed
• webscan_expression_eval_failed
• network_rate_limited
• : (webscan_request_parse_error, poc name)

AI-assisted analysis of shadow1ng/fscan@95cc12e753 (2026-09-06). Data as JSON: /api/errors/05e07917df8eeacb. Report an issue: GitHub.

Appendix: source

Thrown at webscan/lib/Eval.go:174

	var program cel.Program

	if cache != nil {
		if cached, ok := cache[expression]; ok {
			program = cached
		}
	}

	if program == nil {
		ast, issues := env.Compile(expression)
		if issues.Err() != nil {
			return nil, fmt.Errorf("%s: %w", i18n.GetText("webscan_expression_compile_failed"), issues.Err())
		}

		var err error
		program, err = env.Program(ast, GetBaseProgramOptions()...)
		if err != nil {
			return nil, fmt.Errorf("%s: %w", i18n.GetText("webscan_program_create_failed"), err)
		}

		if cache != nil {
			cache[expression] = program
		}
	}

	result, _, err := program.Eval(params)
	if err != nil {
		return nil, fmt.Errorf("%s: %w", i18n.GetText("webscan_expression_eval_failed"), err)
	}

	return result, nil
}

// URLTypeToString 将 TargetURL 结构体转换为字符串
func URLTypeToString(u *UrlType) string {
	var builder strings.Builder

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