Ensure that branch has been updated to point off of master

[lkysow]

Right now we don't check whether a branch has been updated to the latest master. We should just error out if it hasn't, otherwise the plan will be weird.

[grobie]

That wouldn't work well for us. While we don't have a company-wide monorepo, we do have one for all infrastructure changes. There can be tens of unrelated commits in the same repository per hour.

A better approach would be to ensure that the commit of the latest applied state is in the history of the current commit. I'll explain that tomorrow in our call.

[lkysow]

Ahh interesting, I should have thought of that. Right now Atlantis just uses a file-based key-value store which is "okay" to lose because all it records are locks. It might be dangerous to rely on that store for looking up commit => state information.

At some point we'll move to an actual DB which might enable that better. I agree that that would be the most exact way to ensure the pull request is up to date.

[atlantisbot]

This issue was migrated to runatlantis/atlantis#35. Read about why here.