One-Click Compare Environments

Description

We use GitLab CI to deploy to several different environments. Specifically, we have a standard dev, QA, prod flow. Deployments from dev to QA and from QA to prod are manual actions.

When we deploy from QA to prod, we often want to see what changes will happen. Today, we have to copy the commit hashes for QA and prod, navigate to the Project Compare page, and manually paste them. However, it would be very convenient to have a simple way to diff environments.

~"feature proposal"

Proposal

I see two possibilities:

1. Allow environment names to be used in the Project Compare page. We could then insert qa and prod, or even something slightly more complicated (e.g. env:qa and env:prod).
2. Provide a button on the environments page to show a diff with another environment. It could potentially be a dropdown. For example, on our QA environment, there could be a Diff with Prod button or a Diff with... dropdown showing prod as an option (prod being further in the pipeline than QA).

Links / references