Approval Indication on Merge Requests List View

Description

It would be nice to have an easily recognizable visual indication of the assignees which have approved each Merge Request within the list view.

Proposal

It would be nice to have an indicator on the gravatar thumbnail of the assignee(s) showing whether that approver has added their approval on the Merge Requests list view. I imagine the tooltip would display something like "Assigned to dev1, dev2, and dev3. Approved by dev1 and dev3."

Along that vein, it would be nice if the thumbs up and thumbs down counters would display tooltips listing the users which marked each state.

Links / references

Documentation blurb

Overview

Oftentimes I refer to the Merge Requests list to find pending items I have yet to address or approve. If I don't remember whether I had previously reviewed and approved a Merge Request, I must view that Merge Request directly and inspect the list of approvals. Being able to see whether I had already given my approval directly from the list would greatly improve my workflow efficiency.

Use cases

Pretty wide use.

Feature checklist

Make sure these are completed before closing the issue, with a link to the relevant commit.