[ci][microcheck] manually add tests to microcheck

[can-anyscale]

Allow PR owners to add tests to microcheck manually by adding a line with syntax

@microcheck //test_target_01 //test_target_02

to the git commit message. Thanks @stephanie-wang for the great idea.

Note that it's ok to provide an invalid target because tester will re-validate them with bazel query.

Test:

• //release:test_config is manually added and run https://buildkite.com/ray-project/microcheck/builds/169#018f84d5-1024-4285-a3fa-59a96e925563/179-1057

[aslonnie]

I think the idea that allowing users to pick which test to run is great. I am slightly against using git commit message though, as it often leads to weird-looking git commit messages merged into master.

can we use some other means? for example, asking users to manually trigger the pipeline with addtional env var? or maybe this is the time for us to build a GitHub app?

[can-anyscale]

weird-looking git commit messages merged into master

hmm can you elaborate more, when does this happen?

asking users to manually trigger the pipeline with addtional env var

an option yes but it adds more frictions into the people workflow; i'm choosing the git commit message since that's already on the part of people existing workflow so it creates minimal overhead for folks

[can-anyscale]

i think users will prefer git commit messages way more than manually creating builds (i don't understand the github app enough to have an opinion); might be an overkill but we can ask a few OSS engineers if needed for them to choose

the merge message is the github PR description so git commit message is a non-issue as well (understand that some repos merge message is git commit message but it should be a no issue for ray; also for those repos, people often have to self-massage the merge message since the git commit message format is inherently messy anyway)

[can-anyscale]

discussed offline, we agree to go with this solution and redo with another option if we see more than 3 mailformed git commit title caused by this from now until Sep 30th.

[aslonnie]

this is decoding all messages? why not just the last one? I think we just need the last one?

is it possible to just check the git body, but not the title? then there is a lot less risks of having @microcheck polluting the title, and much easier to meet the 0.3% goal.

and I am much more tolerant to having unrelated info in the commit message body.

[can-anyscale]

intentionally all messages yes, so that folks don't need to re-add tests again on every commit update

let me check how to get the body vs title

[can-anyscale]

use format=%b to get the git body only