[reginaldalfret]

Summary

This PR addresses and resolves #326 (Proper logging for withSafeSideEffect).

Problem

In Task.withSafeSideEffect(...), any Throwable thrown during the evaluation of the task provider function (Function1) or callable (Callable) was caught and wrapped into a Task.failure(desc, t) without emitting any log message:

      try {
        Task<?> task = func.apply(param);
        if (task == null) {
          throw new RuntimeException(desc + " returned null");
        }
        return task;
      } catch (Throwable t) {
        return Task.failure(desc, t);
      }

Because withSafeSideEffect is specifically designed to isolate side-effect failures and prevent them from failing the parent execution plan, exceptions thrown during task instantiation failed completely silently without trace in application logs. Callers had no straightforward way to diagnose or debug why a side effect was not created.

Changes

1. Warning Log Output:
   • Added LOGGER.warn("An exception was thrown while creating safe side effect task: " + desc, t); in both the instance withSafeSideEffect(final String desc, final Function1<? super T, Task<?>> func) and static withSafeSideEffect(final String desc, final Callable<Task<T>> func) methods before returning Task.failure(desc, t).
2. Whitespace Correction:
   • Fixed missing space in static withSafeSideEffect: "returned null" -> " returned null", matching instance withSafeSideEffect.
3. Regression Tests:
   • Updated testWithSafeSideEffectFailureInTaskProviderFunction and testStaticWithSafeSideEffectFailureInTaskProviderFunction in AbstractTaskTest.java to attach a TestLogAppender and assert that a WARN level log entry is emitted with the corresponding side-effect description and exception type.

Validation

• Compiled and executed the test suite with Gradle 6.3 on OpenJDK 11:
  • :parseq:test --tests "com.linkedin.parseq.TestTask": 47 passed, 0 failures, 0 errors, 1 skipped (historical).
  • All log assertions verified.

Fixes #326.

Signed-off-by: Reginald Alfret reginaldalfret@gmail.com