EL 3 LambdaExpression failing with an exception irreversibly pollutes variable scope ------------------------------------------------------------------------------------ Key: WFLY-4457 URL: https://issues.jboss.org/browse/WFLY-4457 Project: WildFly Issue Type: Bug Components: EE, Web (Undertow) Affects Versions: 8.2.0.Final Reporter: Paul Pogonyshev Assignee: Tomaz Cerar Labels: el-expresion, patch Attachments: lambda-expression-scoping-fix.diff When a lambda expression is exited with an exception, its variables are left on stack and cannot be removed from it without hacks. My usecase is a customly defined function that uses exceptions as means of non-local exit, but the bug triggers even without custom functions, as demonstrated below. Test case: {noformat} ELProcessor processor = new ELProcessor (); processor.defineBean ("x", null); try { processor.eval ("(x -> x.bug ()) ('bug')"); } catch (RuntimeException exception) { // This is expected, there is no method bug() on strings. } processor.eval ("x"); // This must evaluate to null, but instead evaluates to "bug". {noformat} Proposed fix will be attached as a short patch against 'javax/el/LambdaExpression.java'.