Run github build action on every PR and add test results to the PR checks list

Follow up on https://github.com/eclipse-jdt/eclipse.jdt.core/issues/3552. The https://github.com/eclipse-jdt/eclipse.jdt.core/issues/3552 is discussing unhelpful mails from github CI builds sent "after the fact" for PR's merged to master.

One of the comments there was:

A draft PR creates noise for the project reviewers (who still get a notification) and consume Eclipse CI infra. A GitHub workflow on forks gives contributors CI without involving upstream.

Well, now I'm at upstream and I will CI to show me test results, but they are not visible!

With all the CI actions configured on github as of today, no visible build is executed on draft PR's - neither Github actions nor the Jenkins CI:

However, I get fully unexpected CI mail after ~1 hour, with some console link to download test results which I never manually triggered.

Following this mail link https://github.com/iloveeclipse/eclipse.jdt.core/actions/runs/22067489372 I see some CI results (it is red, but I have no clue why because test output was truncated):

The maven build result consists of every testsuite & test executions xml files:

OK, one think one could get at least some useful test results by following the "Upload Test results for Linux"

But what one gets is a zip file with raw JUnit data. I for sure have no interest to unzip and grep every from thousands xml files for possible failures, that is what "proper" CI integration is supposed to do for me.

This above makes no sense at all.

• If CI build starts, why it is not shown on PR?
• If the results are available, why they are not added to PR?

In the platform and platform UI we have github builds executed & see them started immediately on PR's and the PR's also get the test results published from these github CI builds.

Why shouldn't we have same behavior here?

So my proposal would be:

1. Don't run some "hidden" github CI jobs
2. Run Github CI jobs for every PR (independently if it is a draft or not) before merge to upstream branch
3. Show running Github CI jobs in the github PR's

The benefit would be that we would get a "second opinion" which is helpful if Jenkins doesn't run (as we saw it recently), and this opinion would be visible / results accessible.

However, I have no experience with Github CI pipeline configuration and have no clue how to setup that, I could not find a place where one could enable github CI execution by default and make it actually visible. Any hints?