Make Epics a sub-type of Issues

Problem to solve

Epics are really a specific kind of issue, and should be interchangeable with issues. Current epic functionality is significantly limited because it was implemented as a unique thing and all functionality needs to be reconstructed.

Further details

Specifically, people want:

  1. Group-level issues
  2. Epics on issue boards
  3. Epics on issue boards as value-stream mapping/management
  4. Mingling of epics and issues in a single list (and via the API) so you can, for example, generate a single direction page that shows items of differing "sizes", as long as they have a direction label
  5. Seamlessly convert issues to epics and vice versa
  6. Close epics
  7. Add milestone to epics

Proposal

  1. Convert epics to a sub-type of issues
  2. Make issues available at the group level (this can be a paid feature)
  3. Group issue boards for group issues
  4. Still enforce that the epic sub-type be only available with GitLab Ultimate
  5. Still have additional features available only to epics

What does success look like, and how can we measure that?

Much richer experience both for epics and issues, and faster development velocity.

Links / references