[BUG] Unhandled RuntimeException in PreProcessor or PostProcessor aborts remaining processors, assertions, and cleanup

[rajat315315]

Expected behavior

Description

Currently in JMeterThread.java, execution loops for PreProcessors (runPreProcessors) and PostProcessors (runPostProcessors) do not wrap individual element processing in try-catch blocks.

If any PreProcessor or PostProcessor throws an unhandled RuntimeException (e.g. NullPointerException, IndexOutOfBoundsException, or malformed extraction error):

1. Processor Execution Aborts: The for loop in runPreProcessors / runPostProcessors immediately terminates, skipping all subsequent processors attached to the same sampler.
2. Sampling Pipeline Bypass: Uncaught exceptions in post-processors bypass downstream steps in executeSamplePackage including checkAssertions(), listener notifications (notifyListeners), and compiler resource cleanup (compiler.done(pack)).

By contrast, assertion processing in JMeterThread.processAssertion() explicitly wraps each assertion in try-catch (Exception | JMeterError e) to log errors and allow remaining pipeline elements to execute.

Expected Behavior

When a PreProcessor or PostProcessor throws a runtime exception:

• The error should be logged with the element's name and stack trace.
• The thread should continue executing remaining PreProcessors or PostProcessors.
• Sample assertions, listener notifications, and compiler cleanup should execute normally.

Actual behavior

An exception in a single processor breaks out of the loop, skipping all remaining processors, assertions, and test element cleanup.

Steps to reproduce the problem

In src/core/src/main/java/org/apache/jmeter/threads/JMeterThread.java:

private static void runPostProcessors(List<? extends PostProcessor> extractors) {
    for (PostProcessor ex : extractors) {
        TestBeanHelper.prepare((TestElement) ex);
        ex.process(); // Uncaught RuntimeException breaks loop and caller pipeline
    }
}

### JMeter Version

6.0.0-SNAPSHOT

### Java Version

JDK 17 / JDK 21

### OS Version

_No response_