Summary

This PR fixes how ExtendedTask determines whether to record OpenTelemetry spans. Previously, ExtendedTask checked the OpenTelemetry collection state at invoke() time, which could lead to inconsistent behavior. Now, the OTel recording state is captured when the ExtendedTask is initialized (new()), ensuring consistent span recording behavior regardless of runtime configuration changes.

Changes

• Fixed OTel state capture timing: ExtendedTask now captures the is_recording_otel flag at initialization time rather than checking at invocation time
• Added comprehensive test suite: New test file test-otel-extended-task.R with 219 lines of tests covering various OTel collection scenarios
• Improved documentation: Added "OpenTelemetry Integration" section to ExtendedTask documentation explaining the initialization-time behavior
• Refactored test helpers: Moved mock OTel helper functions to helper-otel.R for reuse across test files

Technical Details

The key change is in R/extended-task.R:169-170, where private$is_recording_otel is now set during initialization:

# Capture this value at init-time, not run-time
private$is_recording_otel <- has_otel_collect("reactivity")

And at invocation time in R/extended-task.R:204, we now check the captured value:

if (private$is_recording_otel) {
  private$otel_span <- start_otel_span(...)
}

Test Coverage

New tests verify:

• OTel state is captured at initialization for all collection levels (all, reactivity, session, none)
• Runtime changes to OTel configuration don't affect already-initialized tasks
• Spans are only created when is_recording_otel is TRUE
• Multiple invocations use the same captured OTel state