checkout `branches` parameter does not seem to work when a job is triggered by a webhook.

[gypark]

Jenkins and plugins versions report

Environment

Jenkins: 2.528.3
OS: Linux - 5.15.0-152-generic
Java: 21.0.9 - Eclipse Adoptium (OpenJDK 64-Bit Server VM)
---
ant:520.vd082ecfb_16a_9
antisamy-markup-formatter:173.v680e3a_b_69ff3
apache-httpcomponents-client-4-api:4.5.14-269.vfa_2321039a_83
apache-httpcomponents-client-5-api:5.6-183.ve5a_8a_b_e71e59
asm-api:9.9.1-189.vb_5ef2964da_91
authentication-tokens:1.144.v5ff4a_5ec5c33
blueocean:1.27.25
blueocean-autofavorite:1.2.5
blueocean-bitbucket-pipeline:1.27.25
blueocean-commons:1.27.25
blueocean-config:1.27.25
blueocean-core-js:1.27.25
blueocean-dashboard:1.27.25
blueocean-display-url:2.4.4
blueocean-events:1.27.25
blueocean-git-pipeline:1.27.25
blueocean-github-pipeline:1.27.25
blueocean-i18n:1.27.25
blueocean-jira:1.27.25
blueocean-jwt:1.27.25
blueocean-personalization:1.27.25
blueocean-pipeline-api-impl:1.27.25
blueocean-pipeline-editor:1.27.25
blueocean-pipeline-scm-api:1.27.25
blueocean-rest:1.27.25
blueocean-rest-impl:1.27.25
blueocean-web:1.27.25
bootstrap5-api:5.3.8-895.v4d0d8e47fea_d
bouncycastle-api:2.30.1.82-277.v70ca_0b_877184
branch-api:2.1268.v044a_87612da_8
build-timeout:1.39
build-user-vars-plugin:212.vd6b_e9f6d0cdb_
caffeine-api:3.2.3-194.v31a_b_f7a_b_5a_81
checks-api:373.vfe7645102093
cloudbees-bitbucket-branch-source:937.2.3
cloudbees-folder:6.1073.va_7888eb_dd514
command-launcher:123.v37cfdc92ef67
commons-collections4-api:4.5.0-8.va_d5448ef9011
commons-compress-api:1.28.0-2
commons-lang3-api:3.20.0-109.ve43756e2d2b_4
commons-text-api:1.15.0-210.v7480a_da_70b_9e
copyartifact:770.va_6c69e063442
credentials:1453.v9b_a_29777a_b_fd
credentials-binding:702.vfe613e537e88
data-tables-api:2.3.5-1497.v38449eb_7d5a_1
display-url-api:2.217.va_6b_de84cc74b_
docker-commons:457.v0f62a_94f11a_3
docker-workflow:634.vedc7242b_eda_7
durable-task:639.vefb_3d8372f6d
echarts-api:6.0.0-1165.vd1283a_3e37d4
eddsa-api:0.3.0.1-19.vc432d923e5ee
email-ext:1933.v45cec755423f
external-monitor-job:223.vb_fddcf42c9b_3
favorite:2.253.v9b_413168133b_
font-awesome-api:7.1.0-882.v1dfb_771e3278
git:5.8.1
git-client:6.5.0
git-server:137.ve0060b_432302
github:1.45.0
github-api:1.330-492.v3941a_032db_2a_
github-branch-source:1917.v9ee8a_39b_3d0d
gitlab-plugin:1.9.13
gradle:2.18.1203.v2c96b_1243c72
gson-api:2.13.2-173.va_a_092315913c
handy-uri-templates-2-api:2.1.8-38.vcea_5d521d5f3
htmlpublisher:427
instance-identity:203.v15e81a_1b_7a_38
ionicons-api:94.vcc3065403257
jackson2-api:2.20.1-423.v13951f6b_6532
jakarta-activation-api:2.1.4-1
jakarta-mail-api:2.1.5-1
jakarta-xml-bind-api:4.0.6-10.v9b_7e1d1fc40b_
javadoc:354.vee1a_660b_4990
javax-activation-api:1.2.0-8
javax-mail-api:1.6.2-11
jaxb:2.3.9-133.vb_ec76a_73f706
jdk-tool:83.v417146707a_3d
jenkins-design-language:1.27.25
jersey2-api:2.47-165.ve7809a_3e87e0
jersey3-api:3.1.11-4.v77818819c2e1
jira:3.21
jjwt-api:0.11.5-120.v0268cf544b_89
joda-time-api:2.14.0-149.v1c3ce991d1b_9
jquery3-api:3.7.1-619.vdb_10e002501a_
jsch:0.2.16-95.v3eecb_55fa_b_78
json-api:20251224-185.v0cc18490c62c
json-path-api:2.10.0-202.va_9cc16c1e476
jsoup:1.21.2-66.v6ea_38164b_8a_2
junit:1369.v15da_00283f06
ldap:793.v754d6b_41b_ea_4
locale:614.va_6a_5a_1a_f2b_38
lockable-resources:1438.v3c0f8c9e2060
mailer:525.v2458b_d8a_1a_71
mapdb-api:1.0.9-44.va_1e1310c9118
matrix-auth:3.2.9
matrix-project:870.v9db_fcfc2f45b_
maven-plugin:3.27
mercurial:1323.ve69d2a_db_8a_b_d
mina-sshd-api-common:2.16.0-167.va_269f38cc024
mina-sshd-api-core:2.16.0-167.va_269f38cc024
okhttp-api:4.12.0-195.vc02552c04ffd
oss-symbols-api:424.ved751e062911
pam-auth:1.12
pipeline-build-step:571.v08a_fffd4b_0ce
pipeline-github-lib:65.v203688e7727e
pipeline-graph-analysis:245.v88f03631a_b_21
pipeline-groovy-lib:787.ve2fef0efdca_6
pipeline-input-step:540.v14b_100d754dd
pipeline-milestone-step:138.v78ca_76831a_43
pipeline-model-api:2.2277.v00573e73ddf1
pipeline-model-definition:2.2277.v00573e73ddf1
pipeline-model-extensions:2.2277.v00573e73ddf1
pipeline-rest-api:2.38
pipeline-stage-step:322.vecffa_99f371c
pipeline-stage-tags-metadata:2.2277.v00573e73ddf1
pipeline-stage-view:2.38
pipeline-utility-steps:2.20.0
plain-credentials:199.v9f8e1f741799
plugin-util-api:6.1192.v30fe6e2837ff
prism-api:1.30.0-630.va_e19d17f83b_0
publish-over:0.22
publish-over-ssh:390.vb_f56e7405751
pubsub-light:1.19
resource-disposer:0.25
scm-api:724.v7d839074eb_5c
script-security:1385.v7d2d9ec4d909
slack:795.v4b_9705b_e6d47
snakeyaml-api:2.5-143.v93b_c004f89de
sonar:2.18.2
sse-gateway:1.28
ssh-credentials:361.vb_f6760818e8c
ssh-slaves:3.1085.vc64d040efa_85
sshd:3.374.v19b_d59ce6610
structs:362.va_b_695ef4fdf9
subversion:1292.ve8cf25770ee3
timestamper:1.30
token-macro:477.vd4f0dc3cb_cf1
trilead-api:2.284.v1974ea_324382
variant:70.va_d9f17f859e0
workflow-aggregator:608.v67378e9d3db_1
workflow-api:1384.vdc05a_48f535f
workflow-basic-steps:1098.v808b_fd7f8cf4
workflow-cps:4238.va_6fb_65c1f699
workflow-durable-task-step:1464.v2d3f5c68f84c
workflow-job:1559.va_a_533730b_ea_d
workflow-multibranch:821.vc3b_4ea_780798
workflow-scm-step:466.va_d69e602552b_
workflow-step-api:710.v3e456cc85233
workflow-support:1010.vb_b_39488a_9841
ws-cleanup:0.49

What Operating System are you using (both controller, and any agents involved in the problem)?

Linux Ubuntu 24.04
Jenkins docker image: jenkins:2.528.3-lts-jdk21

Reproduction steps

1. Create a pipeline job in Jenkins
   1. Triggers : Build when a change is pushed to Gitlab. Gitlab webhook URL: ****
      1. Check Push Events
   2. Pipeline: Definition script from SCM
      1. SCM: Git
      2. Branches to build: */stage
      3. Script Path: Jenkinsfile
2. Create a Jenkinsfile

pipeline {
  agent none
// At first, show the current branch and commit ID.
  stages {
      stage('Check workspace branch') {
          agent any
          steps {
              sh 'pwd; echo "[workspace] branch=$(git branch --show-current) commit=$(git rev-parse --short HEAD)"'
          }
      }
      stage('Checkout another branch into a subdirectory') {
          agent any
          steps {
// Create a subdirectory, then checkout `dev` branch (different from the job build branch)
              dir('branch-dev') {
                  checkout scmGit(
                      branches: [[name: 'dev']],
                      userRemoteConfigs: [[url: scm.userRemoteConfigs[0].url]],
                  )
                  sh 'pwd; echo "[branch-dev subdirectory] branch=$(git branch --show-current) commit=$(git rev-parse --short HEAD)"'
              }
          }
      }
  }
}

3. Push stage branch to the repository so that this job can be started by webhook call
4. Start this job manually. Compare the results.

Expected Results

In both cases:

• the branch of the workspace itself is stage.
  • More precisely, detached HEAD points to the commit of stage branch
• the branch of the branch-dev subdirectory is dev
  • detached HEAD points to the commit of dev branch

Actual Results

Jenkinsfile.txt
Jenkins_output_2_manual.txt
Jenkins_output_1_webhook.txt

When built manually, the result is exactly as expected.

...
[workspace] branch= commit=eec6fc17
...
[branch-dev subdirectory] branch= commit=b584d6d6
...

(eec6fc17 : stage, b584d6d6 : dev)

However, when the job is triggered by the webhook, detached HEAD is at the commit of stage, not dev

[workspace] branch= commit=eec6fc17
...
[branch-dev subdirectory] branch= commit=eec6fc17

Anything else?

I don’t have sufficient knowledge of Git and Jenkins, so I’m not sure whether this is a bug or not. I apologize for that.

While searching for related information, I found the following discussion that seems related:
https://www.reddit.com/r/jenkinsci/comments/1nwfqfy/jenkins_not_respecting_scmbranches_when_triggered

Thank you.

Are you interested in contributing a fix?

No response

[pavankalyan091]

Hi, I would like to work on this issue.
Please let me know if I can proceed.
Thank you.

[MarkEWaite]

Hi, I would like to work on this issue. Please let me know if I can proceed. Thank you.

I don't think that this issue is well suited to a new contributor. It involves many interactions between components and systems. I think you would do better to choose a different issue.

If you decide to work on the issue, please be aware that I expect that you will rigorously follow the contributing guidelines, interactively test every change, add automated tests for every change, and make corrections when requested. There are many ways things that you need to be sure that you do as part of fixing an issue in the git plugin. Please carefully read this comment before deciding to work on this issue.

[pavankalyan091]

Thank you for the guidance.

I understand that this issue is complex and not well suited for a first-time contributor. I will look for a simpler issue to get familiar with the codebase and contributing process, and come back to this later.

Thanks again for the clarification.