Automagically migrating golangci-lint configuration to v2 with Renovate

As mentioned in Using Renovate to manage updates to golangci-lint versions I very much recommend using Renovate to update your golangci-lint versions.

With the release of golangci-lint v2 a couple of weeks ago, consumers need to perform a one-time migration of their configuration.

(I'd meant to post this last week, but yay ADHD, I forgot 🫣)

However, one thing that came with the upgrade was that for each and every PR you get from Renovate, you need to check out the code locally and i.e. run:

# i.e. for my setup
rm -r bin/golangci-lint
make golangci-lint
bin/golangci-lint migrate
git add .golangci.yml
git commit --amend
# not -with-lease=ref (https://www.jvt.me/posts/2018/09/18/safely-force-git-push/)
git push --force

This is a little tedious, albeit heavily scriptable.

So how do we get Renovate to do this for us, given it knows there's a major version bump to upgrade to?

This only works if you're self-hosting Renovate, where you have access to allowedCommands which allowlists arbitrary commands to be run by repository configuration.

Therefore, in our global self-hosting configuration we want to set:

{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "packageRules": [
    {
      "matchPackageNames": [
        "github.com/golangci/golangci-lint"
      ],
      "matchUpdateTypes": [
        "major"
      ],
      "postUpgradeTasks": {
        "commands": [
          "make golangci-lint && bin/golangci-lint migrate"
        ],
        "executionMode": "branch",
        "fileFilters": [
          "^Makefile$",
          ".golangci.y*ml"
        ]
      }
    }
  ],
  "allowedCommands": [
    "^make golangci-lint && bin/golangci-lint migrate$"
  ]
}

This ensures that for any repository across this Renovate's usage, it will:

• find major upgrades from v1 of golangci-lint (as a Go module on v1, it does not have a semantic import path)
• run make golangci-lint to install the golangci-lint binary, which should install into bin
• run bin/golangci-lint migrate to migrate the configuration

If at any point this fails, for instance if the repository doesn't have a make golangci-lint task, or doesn't install into bin, this will fail, and the PR will still require manual handling.

But for those that do work, this shaves off a chunk of time of getting these PRs merged and onto using the latest-and-greatest 🚀