Fix eventlistener crash with multiple interceptors extensions

[larhauga]

When multiple interceptors are present in an event listener and they produce an extension, a race condition can occur due to a global variable written to in a goroutine.

It is possible that this also affects which pipelines could be triggered if the extensions are used for trigger routing.

Changes

A global shared variable was being written to when extensions were
present in the interceptor output. This resulted in a race condition
verified by go test -race ./pkg/sink with the new test.

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Release Notes

• Bug fixes

Fix race condition in eventlistener when multiple interceptors return extentions

[linux-foundation-easycla]

The committers are authorized under a signed CLA.

• ✅ Lars Haugan (d754f90)

[tekton-robot]

Hi @larhauga. Thanks for your PR.

I'm waiting for a tektoncd member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[dibyom]

/ok-to-test

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-triggers-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/sink/sink.go	75.8%	77.9%	2.2

[dibyom]

Thank you @larhauga This was a great find.

I have one minor comment on the test. If you are particularly motivated to fix that in this PR, that is fine -- just open an issue for it :)

/approve

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dibyom

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[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-triggers-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/sink/sink.go	75.8%	75.9%	0.1

[larhauga]

Thank you @larhauga This was a great find.

I have one minor comment on the test. If you are particularly motivated to fix that in this PR, that is fine -- just open an issue for it :)

My pleasure! The tests are updated with the your suggestion of a function for the TT.

[dibyom]

Thank you! Looks great
/lgtm