How best to optimize automerge settings

[aub]

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I'm trying to figure out how to get a good setup with automerge, but everything I've tried doesn't quite work the way I'd expect and creates new problems. I'm on GitHub and I have a number of package rules set up to automerge. Here's what I've tried:

• Setting "rebaseWhen": "conflicted". With this setting, renovate won't rebase branches when they fall behind main, and it won't merge them that way even though my branch protection rules would allow it. So if it creates a set of branches at about the same time and then one of them gets merged then all the other ones will be behind main, fail to automerge, and require manual intervention.

• So, I tried setting "rebaseWhen": "behind-base-branch". This created two new problems. First, it causes a whole lot of thrashing on the branches renovate creates, where CI gets run on them over and over again as each branch is merged in succession and then the other ones get rebased to it. Also, if a branch required us to make changes to fix an issue, renovate would force push to it and overwrite our changes whenever a rebase was needed. For some reason in this mode it doesn't do the thing where it will not automatically rebase this PR, because it does not recognize the last commit author.

• This made me wonder if I could group the automerge rules and then run renovate on a schedule, so a single automerge branch would be created with all of the changes and avoid the problem of the branches causing one another to need updates. I added the "schedule:daily" preset and set "groupName": "daily-dependency-auto-updates" on each of my package rules that do automerge. With this setting, no changes would be added at all unless renovate happened to get triggered during the schedule window, so we mostly just missed the updates altogether.

I'd love a way to have the changes automerge without manual intervention, without a ton of thrashing in CI, and without stomping on changes we make to fix issues. Is there an automerge setup that can balance these things? Specifically, I wonder if setting up a GitHub merge queue would solve it. Since the merge queue is designed to ensure that changes are tested together prior to merging into main, would using one allow renovate to merge changes into it even if they are behind the main branch? Or is there another way to optimize automerge?

Thanks so much!

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[github-actions[bot]]

Hi there,

We need more information about your environment.

Please explain in detail how you are running Renovate. For example:

• Are you running via an official Renovate image, or using the Renovate npm package?
• Which exact image tag are you running?
• Which config/parameters are you using when running the image?
• Which config are you using in your CI/CD pipeline, if relevant?

Thanks, the Renovate team

[aub]

We're running renovate via the GitHub app. We're not self-hosting it. Here is my configuration with most of the package rules removed for brevity:

{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "extends": [
    "config:recommended",
    "schedule:daily"
  ],
  "enabled": true,
  "ignorePaths": [
    "**/node_modules/**",
    "**/packages/frontend/android/**",
    "**/packages/frontend/ios/**"
  ],
  "commitMessagePrefix": "chore: ",
  "commitMessageSuffix": " (renovate)",
  "packageRules": [
    {
      "matchDepTypes": [
        "devDependencies"
      ],
      "matchUpdateTypes": [
        "minor"
      ],
      "automerge": true,
      "automergeType": "branch"
    }
  ],
  "prConcurrentLimit": 20,
  "prHourlyLimit": 0,
  "rangeStrategy": "update-lockfile",
  "rebaseWhen": "conflicted"
}

Our CI/CD pipeline uses GitHub Actions. I don't think the exact configuration for the actions is relevant, but we do have some actions that are required to test prior to merging branches and PRs.

[aub]

How about some very specific questions about how this works:

1. Is there any way to get renovate to automerge branches even if they are behind the main branch?

2. If I use a merge queue, will that allow branches to be automerged even if they are behind main?

3. When using "rebaseWhen": "behind-base-branch", can I tell renovate not to rebase if I have pushed changes to the branch myself? Or is there another rebase setting that will rebase when behind but not if I have pushed to the branch?

4. Is it possible to get renovate to run once per day and make a single branch that batches up all of the automerge-able changes?