in saml-authentication-server/src/main/java/jetbrains/buildServer/auth/saml/plugin/utils/SpelExpressionExecutor.java [22:28]
public String evaluate(String expressionString, SpelExpressionContext context) {
log.debug(String.format("Evaluating expression: %s", expressionString));
var expression = parser.parseExpression(expressionString);
String result = (String) expression.getValue(context.getEvaluationContext());
log.debug(String.format("Evaluation result: %s", result));
return result;
}