Error "Failed to determine code owners for PR." when using assigneesFromCodeOwners

[dschafhauser]

What Renovate type are you using?
Self-hosted via docker image 'renovate/renovate:20.25.5' on own GitLab instance.

Describe the bug

I've enabled the assigneesFromCodeOwners options as described in the docs:
https://docs.renovatebot.com/configuration-options/#assigneesfromcodeowners

However, renovate consistently fails to determine code owners for the PRs it creates.

Did you see anything helpful in debug logs?

WARN: Failed to determine code owners for PR. (repository=my-repository, branch=renovate/some-dependency-)
"err": {
  "message": "Cannot read property 'every' of null",
  "stack": "TypeError: Cannot read property 'every' of null
    at /usr/src/app/node_modules/renovate/dist/workers/pr/code-owners.js:35:59
    at Array.find (<anonymous>)
    at Object.codeOwnersForPr (/usr/src/app/node_modules/renovate/dist/workers/pr/code-owners.js:35:36)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
    at async addCodeOwners (/usr/src/app/node_modules/renovate/dist/workers/pr/index.js:24:55)
    at async addAssigneesReviewers (/usr/src/app/node_modules/renovate/dist/workers/pr/index.js:29:21)
    at async Object.ensurePr (/usr/src/app/node_modules/renovate/dist/workers/pr/index.js:226:17)
    at async Object.processBranch (/usr/src/app/node_modules/renovate/dist/workers/branch/index.js:452:42)
    at async Object.writeUpdates (/usr/src/app/node_modules/renovate/dist/workers/repository/process/write.js:25:21)
    at async Object.update (/usr/src/app/node_modules/renovate/dist/workers/repository/process/extract-update.js:60:15)
    at async Object.renovateRepository (/usr/src/app/node_modules/renovate/dist/workers/repository/index.js:40:21)
    at async Object.start (/usr/src/app/node_modules/renovate/dist/workers/global/index.js:94:13)
    at async /usr/src/app/node_modules/renovate/dist/renovate.js:28:24"
}

To Reproduce

I haven't set up a minimal example to reproduce yet.

Additional context

None.

[rarkins]

I've fixed this particular warning, but I suspect there may be another problem, because prFiles shouldn't be empty. Cc @fgreinacher

[renovate-release]

🎉 This issue has been resolved in version 20.25.8 🎉

The release is available on:

• GitHub release
• 20.25.8

Your semantic-release bot 📦🚀