# gerris workflow

flowchart TD;
    pr_is_merged[Pull request is merged with bors or bors-like] --> commit_to_gcc_patch_dev;
    subgraph commit_to_gcc_patch_dev[Commit to `gcc-patch-dev`];
        commit[For each commit];
        commit --> prefix[Prefix with 'gccrs: ']
        prefix --> push[Push to `gcc-patch-dev`]
    end;
    pr_approved[Pull request is approved] --> bootstrapchecks;
    subgraph bootstrapchecks[Bootstrap checks];
        eachcommit[For each commit];
        eachcommit --build on sourceware machines-->archs 
        eachcommit --test on sourceware machines-->archs
        eachcommit --bootstrap on sourceware machines-->archs
    end
    subgraph archs[Sourceware architectures];
        PPC32;
        S390X;
        i386;
        ARM32;
    end
    pr[Pull request is opened] --> check1;
    subgraph check1[Basic checks];
        codingstyle[coding style] --OK--> compilation --OK--> tests;
    end
    check1 --PASS--> check2;
    subgraph check2[Multi-target compilation + tests];
        GCC48[GCC 4.8];
        Linux-32bits;
        MacOS;
        Windows;
    end check2;
    subgraph check3[Commit checks];
        Changelogs
    end 
    archs --FAIL-->stop2[STOP];
    check2 --PASS--> check3;
    check3 --FAIL--> stop;
    check2 --FAIL--> stop;
    check1 --FAIL--> stop[STOP];

- [ ] On PR approved, run warning, build and tests
- Having `warning`, `build` and `test` should be enough to ensure `bootstrap` passes
- If it does not, it's an extremely weird failure that we can take care of by hand
- [x] Run Changelog checks on each commit
- [x] Run `gccrs: ` prefix checks on each commit
- [x] Run DCO signoff checks on each commit
- [ ] Add branch protection rules to make sure PRs only get merged with all commits warning-free, building and passing the testsuite
- [ ] Improve `actions/checkout` speed?
- [ ] Is that possible? Just a regular checkout does not allow fetching the rev-list
- [ ] Fixed by running on a runner with the repo and cache
- [ ] Turn this into a standalone app?
- [ ] Easier to maintain
- [ ] Easier to improve
- [ ] Easier to eventually parallelize?
- [ ] Create a light self-contained docker image for `gerris`
- [ ] How to integrate buildbot?
- Keep buildbot as a test for multiple architectures which runs after the fact
- Run it before merging thanks to a hook
- [ ] How to get `gerris` to post messages on github?
- [ ] Add a cron job so that `gerris` picks commits from master every week, rebases them on `gcc-patch-dev` (prefixed with `gccrs: `) and opens a PR
- [ ] How to deal with CI timeout?
- A job must complete in 6 hours
- Each bootstrap build takes 3 hours
- This is why we need a custom runner with `ccache` and the git repo
- This is also why doing warning checking + build + test should be good enough
- [ ] Can we have `gerris` post PR reviews?
- [ ] Approved if all checks pass
- [ ] Comment if some timeout
- [ ] Request changes if steps are failing, with a helpful comment of what is failing
- [ ] Add Windows CI as well
- [ ] Do not run all these checks on PRs with the `merge` label

- Pseudo code:

for commit in rev_list {
    warning_check(commit)?;
    build(commit)?;
    run_tests(commit)?;
    check_test_output(commit)?;
}

flowchart TD;
    github --weekly cron job--> gerris;
    gerris --updates commits--> gerris;
    gerris --creates PR--> github;

Maybe a good first step would be to have a weekly cron job which takes commits from master and creates a PR to `gcc-patch-dev`?