Go workspace artifact update notices exceed GitHub's 65,536-char comment limit; 422 classified as external-host-error aborts entire run

[lauraseidler]

How are you running Renovate?

None

Which platform you running Renovate on?

GitHub.com

Which version of Renovate are you using?

44.41.1

Please tell us more about your question or problem

In a large Go workspace (go.work with 60+ modules), updating a single dependency that many modules depend on causes Renovate to generate artifact update notices listing all the changed go.mod/go.sum files. For broadly-depended-on packages, this list exceeds GitHub's 65,536-character comment body limit.

What happens:

1. Renovate updates the Go dependency and resolves go.mod/go.sum changes across the workspace.
2. It attempts to POST the artifact update comment to the PR.
3. GitHub returns HTTP 422 — body too large.
4. Renovate classifies the 422 as external-host-error.
5. The entire Renovate run is marked failed. All other updates are blocked.

This has hit us for multiple packages so far, our workaround is to add each to an "enabled": false packageRule as we discover them, which we have to update manually every time a new package hits the limit, and of course means that we need to manually update these packages.

Additionally (and even more impactful), a single PR's comment failure aborts the entire run. Even if truncating the comment isn't feasible, handling the 422 gracefully (log a warning, continue the run) would prevent failing the run and allowing other dependencies to be updated.

Suggested fixes (any one would help, but probably both is best):

• Truncate artifact update comments that exceed the GitHub limit, with a note that the list was cut short, or split into multiple comments if the content is too large for one.
• Don't classify a 422 body-too-large as external-host-error — skip posting that specific comment and continue the run.

Happy send a PR

Logs (if relevant)

Logs

  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-a>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-b>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-c>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-d>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-e>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-f>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-g>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-h>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-i>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-j>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-k>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-l>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-m>/go.mod
  DEBUG: Updating cloud.google.com/go/cloudtasks in <service-n>/go.mod
    [... many more modules ...]
  DEBUG: gomod.updateArtifacts(<service-a>/go.mod)
  DEBUG: Getting comments for #<PR>
  DEBUG: Found 0 comments
  DEBUG: Ensuring comment "ℹ️ Artifact update notice" in #<PR>
  DEBUG: POST https://api.github.com/repos/<org>/<repo>/issues/<PR>/comments =
         (code=ERR_NON_2XX_3XX_RESPONSE, statusCode=422 retryCount=0, duration=352)
  ERROR: Host error {
    "code": "ERR_NON_2XX_3XX_RESPONSE",
    "message": "Request failed with status code 422 (Unprocessable Entity): POST https://api.github.com/repos/<org>/<repo>/issues/<PR>/comments",
    "options": {
      "content-length": "306457",
      "content-type": "application/json",
      "user-agent": "Renovate/44.41.1 (https://github.com/renovatebot/renovate)"
    },
    "response": {
      "body": {
        "errors": [{"code": "unprocessable", "field": "data",
          "message": "Body is too long (maximum is 65536 characters)",
          "resource": "IssueComment"}],
        "message": "Validation Failed",
        "status": "422"
      },
      "statusCode": 422
    }
  }
  WARN:  422 Error thrown from GitHub
  WARN:  External host error causing abort - skipping
  INFO:  Repository result: external-host-error, status: onboarded