Make data/team.yml eventually consistent

To support users who edit the team directory through the web interface, here we change the pipeline so that:

• verify_team only runs on merge requests

  • if the team directory has changed from master, we only check the changes in the team directory
  • otherwise we verify full consistency

• on master we run update-team

  • here we check that the team.yml file reflects the contents of the team directory
  • if it does not, then we update it so that it does, and push the resulting file to master.

For this to work, data/team.yml must never be updated in merge requests, and we must only run verify_team on merge requests.

We use ci.skip to avoid creating a subsequent pipeline.

See:

• !73835 (closed) which prevents changes to data/team.yml in MRs
• !73798 (closed) which adds extra verification (needs to be merged first)
• !73139 (merged) which implements the split, after which this becomes necessary

This can be merged first

Data Flow

The data flow is:

flowchart TB    
    subgraph mrpl [Phase One]
     UserEditsTeam[/User edits data/team.yml\] -->|triggers| MRPL_a(MR pipeline)
     StartBad[/User edits data/team_members/person/x/ab.yml\] -->|triggers| MRPL_c(MR pipeline)
     Start[/User edits data/team_members/person/a/ab.yml\] -->|triggers| MRPL_b(MR pipeline)
     BotStart[/gitlab-bot edits data/team.yml\] -->|triggers| MRPL_b(MR pipeline)
    
      MRPL_a -->|runs| DJ_a{danger}
      MRPL_b -->|runs| DJ_b{danger}
      DJ_a -->|MR touches team.yml| MRAbort
      DJ_b -->|ok| VT_a{validate_team}
      MRPL_c -->|MR changes team members| VT_c{validate_team}
      VT_c -->|invalid?| MRAbort(Merge prevented)
      VT_a -->|ok| Merge(Added to merge train)
    end

    Merge-->MergeTrain[(Merge Train)]
    MergeTrain -->|triggers| MasterPL[Pipeline on master]

    subgraph Phase Two
      MasterPL -->|runs| UT(bundle exec rake build:team_yml)
      UT -->|produces| YAML(team.yml)
      YAML -->|changed?| NeedsUpdate[\create MR editing team.yml/]
      YAML -->|up to date?| Done[\DONE/]
      
    end

    NeedsUpdate -->BotStart

    classDef pipeline fill:#f96;
    class MasterPL,MRPL_a,MRPL_b,MRPL_c pipeline;
    classDef terminal fill:#000000,stroke:#fff,color:#fff;
    class Start,StartBad,UserEditsTeam,Done,Merge,MRAbort terminal;