updateGitlabCommitStatus is not working with Jenkins Merge Request jobs

Jenkins and plugins versions report

Environment

```text Jenkins: 2.414.2 OS: Linux - 5.10.179-168.710.amzn2.x86_64 Java: 11.0.20 - Red Hat, Inc. (OpenJDK 64-Bit Server VM) --- aio-tests:1.8 ansicolor:1.0.4 ant:497.v94e7d9fffa_b_9 antisamy-markup-formatter:162.v0e6ec0fcfcf6 apache-httpcomponents-client-4-api:4.5.14-208.v438351942757 aqua-security-scanner:3.2.4 audit-trail:347.v1fc515cc462b_ authentication-tokens:1.53.v1c90fd9191a_b_ authorize-project:1.7.1 aws-credentials:218.v1b_e9466ec5da_ aws-java-sdk-ec2:1.12.529-406.vdeff15e5817d aws-java-sdk-ecr:1.12.529-406.vdeff15e5817d aws-java-sdk-minimal:1.12.529-406.vdeff15e5817d aws-java-sdk-secretsmanager:1.12.529-406.vdeff15e5817d aws-java-sdk-ssm:1.12.529-406.vdeff15e5817d blueocean:1.27.7 blueocean-autofavorite:1.2.5 blueocean-bitbucket-pipeline:1.27.7 blueocean-commons:1.27.7 blueocean-config:1.27.7 blueocean-core-js:1.27.7 blueocean-dashboard:1.27.7 blueocean-display-url:2.4.2 blueocean-events:1.27.7 blueocean-git-pipeline:1.27.7 blueocean-github-pipeline:1.27.7 blueocean-i18n:1.27.7 blueocean-jwt:1.27.7 blueocean-personalization:1.27.7 blueocean-pipeline-api-impl:1.27.7 blueocean-pipeline-editor:1.27.7 blueocean-pipeline-scm-api:1.27.7 blueocean-rest:1.27.7 blueocean-rest-impl:1.27.7 blueocean-web:1.27.7 bootstrap5-api:5.3.2-1 bouncycastle-api:2.29 branch-api:2.1128.v717130d4f816 build-user-vars-plugin:1.9 caffeine-api:3.1.8-133.v17b_1ff2e0599 checks-api:2.0.2 cloudbees-bitbucket-branch-source:843.vd09104df7988 cloudbees-folder:6.848.ve3b_fd7839a_81 command-launcher:107.v773860566e2e commons-lang3-api:3.13.0-62.v7d18e55f51e2 commons-text-api:1.10.0-78.v3e7b_ea_d5a_fe1 config-file-provider:959.vcff671a_4518b_ configuration-as-code:1700.v6f448841296e content-replace:1.8.2 credentials:1271.v54b_1c2c6388a_ credentials-binding:636.v55f1275c7b_27 custom-tools-plugin:0.8 data-tables-api:1.13.6-4 deployit-plugin:23.2.0 display-url-api:2.3.9 docker-commons:439.va_3cb_0a_6a_fb_29 docker-workflow:572.v950f58993843 durable-task:523.va_a_22cf15d5e0 ec2:1628.v6d7b_fc58b_a_1d echarts-api:5.4.0-6 email-ext:2.101 envinject:2.908.v66a_774b_31d93 envinject-api:1.199.v3ce31253ed13 extended-choice-parameter:376.v2e02857547b_a_ external-monitor-job:215.v2e88e894db_f8 favorite:2.4.3 file-operations:131.v32b_e7824fe95 font-awesome-api:6.4.2-1 fortify:22.2.39 git:5.2.0 git-client:4.5.0 git-server:99.va_0826a_b_cdfa_d github:1.37.3 github-api:1.314-431.v78d72a_3fe4c3 github-branch-source:1741.va_3028eb_9fd21 gitlab-api:5.3.0-91.v1f9a_fda_d654f gitlab-branch-source:677.v0b_63b_038322b_ gitlab-plugin:1.7.16 gradle:2.8.2 groovy:453.vcdb_a_c5c99890 handy-uri-templates-2-api:2.1.8-22.v77d5b_75e6953 hp-application-automation-tools-plugin:23.3.0 htmlpublisher:1.32 http_request:1.18 instance-identity:173.va_37c494ec4e5 ionicons-api:56.v1b_1c8c49374e jackson2-api:2.15.2-350.v0c2f3f8fc595 jakarta-activation-api:2.0.1-3 jakarta-mail-api:2.0.1-3 javadoc:243.vb_b_503b_b_45537 javax-activation-api:1.2.0-6 javax-mail-api:1.6.2-9 jaxb:2.3.8-1 jdk-tool:73.vddf737284550 jenkins-design-language:1.27.7 jersey2-api:2.40-1 jjwt-api:0.11.5-77.v646c772fddb_0 jnr-posix-api:3.1.17-1 jquery:1.12.4-1 jquery3-api:3.7.1-1 jsch:0.2.8-65.v052c39de79b_2 junit:1240.vf9529b_881428 kubernetes:4029.v5712230ccb_f8 kubernetes-client-api:6.8.1-224.vd388fca_4db_3b_ kubernetes-credentials:0.11 ldap:701.vf8619de9160a_ locale:314.v22ce953dfe9e lockable-resources:1185.v0c528656ce04 mailer:463.vedf8358e006b_ matrix-auth:3.2.1 matrix-project:808.v5a_b_5f56d6966 maven-plugin:3.23 metrics:4.2.18-442.v02e107157925 mina-sshd-api-common:2.10.0-69.v28e3e36d18eb_ mina-sshd-api-core:2.10.0-69.v28e3e36d18eb_ node-iterator-api:49.v58a_8b_35f8363 oauth-credentials:0.646.v02b_66dc03d2e oic-auth:2.6 okhttp-api:4.11.0-157.v6852a_a_fa_ec11 pam-auth:1.10 pipeline-build-step:505.v5f0844d8d126 pipeline-graph-analysis:202.va_d268e64deb_3 pipeline-groovy-lib:689.veec561a_dee13 pipeline-input-step:477.v339683a_8d55e pipeline-milestone-step:111.v449306f708b_7 pipeline-model-api:2.2144.v077a_d1928a_40 pipeline-model-definition:2.2144.v077a_d1928a_40 pipeline-model-extensions:2.2144.v077a_d1928a_40 pipeline-rest-api:2.33 pipeline-stage-step:305.ve96d0205c1c6 pipeline-stage-tags-metadata:2.2144.v077a_d1928a_40 pipeline-stage-view:2.33 pipeline-utility-steps:2.16.0 plain-credentials:143.v1b_df8b_d3b_e48 plugin-util-api:3.3.0 pubsub-light:1.17 rebuild:320.v5a_0933a_e7d61 remote-file:1.24 resource-disposer:0.23 saml:4.429.v9a_781a_61f1da_ scm-api:676.v886669a_199a_a_ script-security:1275.v23895f409fb_d snakeyaml-api:2.2-111.vc6598e30cc65 sonar:2.15 sse-gateway:1.26 ssh-agent:333.v878b_53c89511 ssh-credentials:308.ve4497b_ccd8f4 sshd:3.312.v1c601b_c83b_0e structs:325.vcb_307d2a_2782 token-macro:384.vf35b_f26814ec trilead-api:2.84.v72119de229b_7 uno-choice:2.7.2 variant:60.v7290fc0eb_b_cd workflow-aggregator:596.v8c21c963d92d workflow-api:1281.vca_5fddb_3fceb_ workflow-basic-steps:1042.ve7b_140c4a_e0c workflow-cps:3791.va_c0338ea_b_59c workflow-durable-task-step:1289.v4d3e7b_01546b_ workflow-job:1346.v180a_63f40267 workflow-multibranch:756.v891d88f2cd46 workflow-scm-step:415.v434365564324 workflow-step-api:639.v6eca_cd8c04a_a_ workflow-support:865.v43e78cc44e0d ws-cleanup:0.45 ```

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

No related to the issue

Reproduction steps

Activate the "discover merge requests" in Jenkins for the job
Create a merge request
Build the merge request in Jenkins

Inside the merge request, we call the

updateGitlabCommitStatus name: 'build', state: 'success'

Expected Results

On Gitlab, I'm expecting to see this kind of link :

Actual Results

But it's not the case, it's working on branches (as it is on the image) but not on merge requests. I have made the test where an existing Gitlab CI pipeline exist and I have this result :

The first line is the Jenkins plugin result and the 2nd line is the Gitlab CI result. As you see, this "MR-xxx" is the jenkins update not processed as a "merge request" but as a commit.

Anything else?

Gitlab API page is https://docs.gitlab.com/ee/api/commits.html#set-the-pipeline-status-of-a-commit

Gitlab says : Add or update the pipeline status of a commit. If the commit is associated with a merge request, the API call must target the commit in the merge request’s source branch.

Currently on merge requests, the env.BRANCH_NAME is used in your plugin where the source branch should be used in case of merge requests. So maybe if the env.CHANGE_TARGET is not null (which means it's a merge request), use the merge request source branch instead of BRANCH_NAME or maybe you can allow to set a new paramater in the updateGitlabCommitStatus call ?

Are you interested in contributing a fix?

No response

jenkinsci / gitlab-plugin