testUpdateExtensionSubscription is often failing on Pharo12

[jecisc]

This test was previously failing from time to time on Pharo's CI but recently it is almost always failing on Pharo 12 CI but it's almost always on OSX.

This is probably related to something random but maybe it can be used to find the origin? (For example doing a PR with logs in the test to find the origin?)

Example of stack

osx-64 / Tests-osx-64 / testUpdateExtensionSubscription – MacOSX64.NewTools.Debugger.Tests.StDebuggerTest8s
Error
Got 1 instead of 5.
Stacktrace
TestFailure
Got 1 instead of 5.
StDebuggerTest(TestAsserter)>>assert:description:resumable:
StDebuggerTest(TestAsserter)>>assert:description:
StDebuggerTest(TestAsserter)>>assert:equals:
StDebuggerTest>>testUpdateExtensionSubscription
StDebuggerTest(TestCase)>>performTest

https://ci.inria.fr/pharo-ci-jenkins2/blue/organizations/jenkins/Test%20pending%20pull%20request%20and%20branch%20Pipeline/detail/PR-15488/1/tests

Can maybe interest @StevenCostiou or @adri09070

[adri09070]

How can I put logs in Pharo to see something on the CI ?

[jecisc]

If you use a #traceCr it will show in the logs

[adri09070]

Does the error still occur?

I think it happens because the system announcer subscriptions regsistry randomly removes its weak subscriptions that can be removed.

I don't understand how it is possible that some debuggers are still registered to the system announcer after they have been garbage collected though