fix: ValueError "Token was created in a different context"

[aticie]

Fixes an issue that happens with OpenTelemetryMiddleware when a message is requeued with Context.requeue().

Context.requeue() uses self.broker.kick to kick a message to the broker which skips the Middleware pre-send and post-send invocations that kicker does here:

taskiq/taskiq/kicker.py

Lines 160 to 162 in ced1909

	for middleware in self.broker.middlewares:
	if middleware.__class__.pre_send != TaskiqMiddleware.pre_send:
	message = await maybe_awaitable(middleware.pre_send(message))

taskiq/taskiq/kicker.py

Lines 168 to 170 in ced1909

	for middleware in reversed(self.broker.middlewares):
	if middleware.__class__.post_send != TaskiqMiddleware.post_send:
	await maybe_awaitable(middleware.post_send(message))

Messages that are requeued with the same context variables will raise an error on post_save's .detach() because they are now running in a different async context.

The message's lifecycle on OpenTelemetryMiddleware will be:

• pre_send -> message.labels are injected with context here
• post_send
• pre_execute -> message.labels are extracted here and re-used
• post_execute
• requeue() happens -> skipping pre_send and post_send, therefore not renewing the context.
• pre_execute -> context inferred from message.labels again
• post_execute
• post_save -> Detaching the stale context here. Raises ValueError: Token was created in a different context

This change gets rid of post_save on OpenTelemetryMiddleware to detach the context on post_execute instead. Since, we are not actually doing anything database save related on the current post_save method, it seems fair to move everything under post_execute as this is where the task execution actually ends.

[danfimov]

@soapun Can you help me with review here? I remeber that you built opentelemetry integration. Maybe you have an opinion on this change. Thank you)

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.90%. Comparing base (ef92b9e) to head (12aa51e).

Files with missing lines	Patch %	Lines
taskiq/middlewares/opentelemetry_middleware.py	85.71%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #661      +/-   ##
==========================================
- Coverage   82.91%   82.90%   -0.01%     
==========================================
  Files          69       69              
  Lines        2756     2755       -1     
==========================================
- Hits         2285     2284       -1     
  Misses        471      471              

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[s3rius]

This fix for the situation is actually correct.

The only 1 concern I have is that we will skip recording save events. In context of the system it might be okay.

[s3rius]

@aticie, but can you please run prek locally and fix issues? I rebased your PR onto new changes.