Another open merge request already exists for this source branch (409 conflict) although ignorePrAuthor=true

[eidottermihi]

How are you running Renovate?

Self-hosted Renovate

If you're self-hosting Renovate, tell us which platform (GitHub, GitLab, etc) and which version of Renovate.

GitLab / 41.116.1

Please tell us more about your question or problem

We had the need to change the bot account for Renovate so we set the global config option ignorePrAuthor to true and this has be working flawlessly for several months now and at least up to version 41.99.8.

Starting with at least 41.107.0 (or maybe even earlier), we get errors for each repository where the Onboarding MR is still open and where it was initially created by the old bot account (now a "Ghost user"):

"Another open merge request already exists for this source branch"

We configured ignorePrAuthor in the global config file config.js (excerpt):

module.exports = {
  // ...
  ignorePrAuthor: true
};

There are similiar discussions, all suggesting the use of ignorePrAuthor for this kind of problem, e.g. #18431

Logs (if relevant)

Logs

ERROR: Repository has unknown error (repository=exampleorg/examplerepo)
       "err": {
         "name": "HTTPError",
         "code": "ERR_NON_2XX_3XX_RESPONSE",
         "timings": {
           "start": 1758116496767,
           "socket": 1758116496767,
           "lookup": 1758116496772,
           "connect": 1758116496775,
           "secureConnect": 1758116496777,
           "upload": 1758116496777,
           "response": 1758116497070,
           "end": 1758116497070,
           "phases": {
             "wait": 0,
             "dns": 5,
             "tcp": 3,
             "tls": 2,
             "request": 0,
             "firstByte": 293,
             "download": 0,
             "total": 303
           }
         },
         "message": "Response code 409 (Conflict)",
         "stack": "HTTPError: Response code 409 (Conflict)\n    at Request.<anonymous> (/usr/local/renovate/node_modules/.pnpm/got@11.8.6/node_modules/got/dist/source/as-promise/index.js:118:42)\n    at processTicksAndRejections (node:internal/process/task_queues:105:5)",
         "options": {
           "headers": {
             "user-agent": "RenovateBot/41.116.1 (https://github.com/renovatebot/renovate)",
             "accept": "application/json",
             "authorization": "***********",
             "content-type": "application/json",
             "content-length": "3685",
             "accept-encoding": "gzip, deflate, br"
           },
           "url": "https://gitlab.example.com/api/v4/projects/exampleorg%2Fexamplerepo/merge_requests",
           "hostType": "gitlab",
           "username": "",
           "password": "",
           "method": "POST",
           "http2": false
         },
         "response": {
           "statusCode": 409,
           "statusMessage": "Conflict",
           "body": {
             "message": [
               "Another open merge request already exists for this source branch: !1"
             ]
           },
           "headers": {
             "server": "nginx",
             "date": "Wed, 17 Sep 2025 13:41:37 GMT",
             "content-type": "application/json",
             "content-length": "84",
             "connection": "close",
             "cache-control": "no-cache",
             "nel": "{\"max_age\": 0}",
             "vary": "Origin",
             "x-content-type-options": "nosniff",
             "x-frame-options": "SAMEORIGIN",
             "x-gitlab-meta": "{\"correlation_id\":\"01K5BYHHCA2B0ZYA0JH5T3M7WK\",\"version\":\"1\"}",
             "x-request-id": "01K5BYHHCA2B0ZYA0JH5T3M7WK",
             "x-runtime": "0.287356",
             "strict-transport-security": "max-age=63072000"
           },
           "httpVersion": "1.1",
           "retryCount": 0
         }
       }

[RahulGautamSingh]

This is expected as one onboarding pr is open and ignoreprauthor is true meaning the bot recognises the already open pr as its own

[eidottermihi]

Yes, but why is the bot then trying to create a new MR then (POST /v4/projects/exampleorg%2Fexamplerepo/merge_requests, see logs)? It should just update the MR, not try to create a new one.

[eidottermihi]

some more debug logs suggests that the bot thinks that there is no "Onboarding PR" already:

"msg":"findPr(renovate/configure, chore: Configure Renovate, !open)"
"msg":"Onboarding PR does not exist"
"msg":"findPr(renovate/configure, undefined, open)"
"msg":"getBranchPr(renovate/configure)"
"msg":"Repo is not onboarded"
"msg":"Found no closed onboarding PR"

and later:

"msg":"Need to create onboarding PR"
"msg":"createOnboardingBranch()"
// ....
"msg":"ensureOnboardingPr()"
"msg":"getBranchPr(renovate/configure)"
"msg":"findPr(renovate/configure, undefined, open)"
"msg":"Filling in onboarding PR template"
"msg":"getExpectedPrList()"
"msg":"Creating onboarding PR"
"msg":"Creating Merge Request: Configure Renovate",
"msg":"POST https://gitlab.example.com/api/v4/projects/exampleorg%2Fexamplerepo/merge_requests = (code=ERR_NON_2XX_3XX_RESPONSE, statusCode=409 retryCount=0, duration=338)"

At the POST request we get the failure, because there actually is already a Onboarding PR (with source_branch renovate/configure) and so GitLab refuses to create another PR for the same source_branch ("Another open merge request already exists for this source branch").

For me it looks like the detection of "is there an onboarding PR" got broken, especially with ignorePrAuthor=true

[eidottermihi]

running version 41.99.8 the same scenario / same config the bot just updates the PR (as it should)

 INFO: Onboarding PR updated (repository=exampleorg/examplerepo)
       "pr": 1