Method isTautology

pkg/sql/security/scanner.go:780–814

isTautology checks if an expression is always true.

(expr *ast.BinaryExpression)

// isTautology checks if an expression is always true.
func (s *Scanner) isTautology(expr *ast.BinaryExpression) bool {
	if expr == nil {
		return false
	}

	op := strings.ToUpper(expr.Operator)
	if op != "=" && op != "==" {
		return false
	}

	// Check for LiteralValue tautologies: 1=1, 2=2, 'a'='a', etc.
	leftLit, leftIsLit := expr.Left.(*ast.LiteralValue)
	rightLit, rightIsLit := expr.Right.(*ast.LiteralValue)

	if leftIsLit && rightIsLit {
		// Same literal values
		leftVal := fmt.Sprintf("%v", leftLit.Value)
		rightVal := fmt.Sprintf("%v", rightLit.Value)
		if leftVal == rightVal {
			return true
		}
	}

	// Check for identifier tautologies: col=col
	leftIdent, leftIsIdent := expr.Left.(*ast.Identifier)
	rightIdent, rightIsIdent := expr.Right.(*ast.Identifier)

	if leftIsIdent && rightIsIdent {
		if leftIdent.Name == rightIdent.Name {
			return true
		}
	}

	return false
}

// checkOrInjection checks for OR-based injection patterns.
func (s *Scanner) checkOrInjection(expr *ast.BinaryExpression, result *ScanResult) {