Debian tag updated from forky-20260623 to 14

[benbz]

How are you running Renovate?

Self-hosted Renovate CLI

Which platform you running Renovate on?

GitLab (.com or self-hosted)

Which version of Renovate are you using?

44.17.0

Please tell us more about your question or problem

Recent Renovate versions are attempting to upgrade Docker tag that is formatted as a dated Debian codename to an un-dated version number tag. Worse for forky (Debian 14 / current testing), there is no un-dated version number tag.

This appears to be the inverse of #42443 which was solved by #44335. I suspect that that fix is the cause of my problem and it is causing Renovate to always drop the date & convert to a version number rather than maintaining the current format of the tag.

Logs (if relevant)

Logs

         "dockerfile": [
           {
             "deps": [
               {
                 "depName": "docker.io/library/debian",
                 "packageName": "docker.io/library/debian",
                 "currentValue": "forky-20260623",
                 "replaceString": "ARG BASE_IMAGE=docker.io/library/debian:forky-20260623\n",
                 "autoReplaceStringTemplate": "ARG BASE_IMAGE=docker.io/library/debian:{{#if newValue}}{{newValue}}{{/if}}{{#if newDigest}}@{{newDigest}}{{/if}}\n",
                 "datasource": "docker",
                 "versioning": "debian",
                 "depType": "final",
                 "updates": [
                   {
                     "bucket": "non-major",
                     "newVersion": "forky-20260803",
                     "newValue": "14",
                     "releaseTimestamp": "2026-08-05T02:25:55.493Z",
                     "newVersionAgeInDays": 5,
                     "newMajor": 14,
                     "newMinor": null,
                     "newPatch": null,
                     "updateType": "patch",
                     "isBreaking": false,
                     "libYears": 0.11472913470319634,
                     "branchName": "renovate/docker.io-library-debian-14.x"
                   }
                 ],
                 "warnings": [],
                 "sourceUrl": "https://github.com/debuerreotype/docker-debian-artifacts",
                 "registryUrl": "https://index.docker.io",
                 "homepage": "https://hub.docker.com/_/debian",
                 "lookupName": "library/debian",
                 "currentVersion": "forky-20260623",
                 "currentVersionTimestamp": "2026-06-24T05:24:17.501Z",
                 "currentVersionAgeInDays": 47,
                 "isSingleVersion": true,
                 "fixedVersion": "forky-20260623"
               }
             ],
             "packageFile": "Dockerfile"
           }
         ],

[Stetsed]

I can also confirm I am running into this same issue, currently it keeps trying to update from "trixie-20260824" to "13", which is unwanted as I prefer having the explicit dated tag with the name inside of that specific application. I found the same as the above user where it seems to be the inverse of #42443, currently have not been able to find a workaround to it, besides doing what the above user suggested and just manually pinning it.

I am running 44.39.2, on a selfhosted Forgejo Instance with the "Action" runner.