ignore "empty" Go module updates

[jmhodges]

So, I'm getting lots of PRs like jmhodges/lekube#94, where the only changes are to the commit hash in the 3 files managed by the Go module system. There's no actual code changes in there beyond the version bump, because the Go module system (correctly) sees there were no relevant updates to the subpackages used by lekube.

It'd be cool if these "empty" PRs didn't happen. I get them every few days because those repos have new commits often. It's making pay less attention to all of my renovate PRs, because these "empty" PRs are far more common than the useful PRs.

[rarkins]

Do you have any ideas for how Renovate could "know" that? e.g. would an option "skip the PR completely if there's no change to vendor/" work?

[jmhodges]

If the update only changes the files go.mod, go.sum, and vendor/modules.txt, then it's an empty one. So, "almost yes" to your question because vendor/modules.txt always changes when the commit sha is bumped even though no code does.

[rarkins]

Is the only way to determine this is after go mod vendor and check the results?

[jmhodges]

Since I don’t know renovate’s codebase, I don’t think I can answer the question

[rarkins]

It's a Go question, not a Renovate question. If a Go dependency is not using modules (uses commits instead) and the commit is updated, can you tell if it's an "empty" change without running go mod vendor?

[jmhodges]

Man, I’m sorry but I’m doing this on my free time. I have no idea how deep into the guts you need to go to not run the whole “go mod vendor” stuff. There’s clearly a world in which you can dig into that code to do less work but I have no idea what it entails

[github-actions]

Hi there,

Help us by making a minimal reproduction repository.

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We may close the issue if you (or someone else) have not provided a minimal reproduction within two weeks. If you need more time, or are stuck, please ask for help or more time in a comment.

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[thejan2009]

Hello there,
except for the files created by go mod vendor, I haven't found any other way to list changed dependency source code when upgrading a go.mod file.

Is there a way to gracefully abort and then ignore the upgrade with a PostUpgradeTask? That would allow us to detect and solve the above issue in a self-hosted deployment.

[rarkins]

Possibly a script which:

• Uses git to check for any changes to the vendor dir
• If no changes to the vendor dir, it uses git to reset the go.mod and go.sum values back to the base branch

Although manipulating git is usually not a good idea, this might end up working if it tricks Renovate into thinking there's no changes and to skip the branch.

Essential that someone can create a reproduction

[thejan2009]

See here: https://github.com/thejan2009/renovate-go-5123

catch.sh attempts to do what you described, but for some reason resetting the git folder does nothing and Renovate still finds the 3 files to update (go.mod, go.sum and vendor/modules.txt).

Edit: we want github.com/stretchr/testify@v1.8.0 to be upgraded only if there are changes

[rarkins]

I got a little further by modifying your renovate.json to include fileFilters: https://github.com/renovate-reproductions/5123/blob/main/renovate.json

And I confirmed manually that the comment correctly reset the values.

The problem is that today we match fileFilters against the output of git status.. which returns empty. I can think of a way to fix this hopefully

[rarkins]

Confirmed I could get the anticipated result with a bit of code mod:

 WARN: Detected empty commit - aborting git push (repository=renovate-reproductions/5123, branch=renovate/github.com-stretchr-testify-1.x)
       "commitRes": {
         "author": null,
         "branch": "",
         "commit": "",
         "root": false,
         "summary": {"changes": 0, "insertions": 0, "deletions": 0}
       }

But I need to think if there's a cleaner way

[rarkins]

Blocked by #18609