Jenkins Git plugin detached HEAD

user_1400597 0
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I am new to Git and also to Jenkins. My problem is that I can't get the Jenkins Maven release plugin to work.

When I build a common Maven build with Jenkins, it works well, but when I try to perform a release with the Maven release plugin, I get the following stack trace:

org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-release-plugin:2.3.2:prepare (default-cli) on project parent: An error is occurred in the checkin process: Exception while executing SCM command.
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:217)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
    at org.jvnet.hudson.maven3.launcher.Maven3Launcher.main(Maven3Launcher.java:79)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchStandard(Launcher.java:329)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:239)
    at org.jvnet.hudson.maven3.agent.Maven3Main.launch(Maven3Main.java:158)
    at hudson.maven.Maven3Builder.call(Maven3Builder.java:98)
    at hudson.maven.Maven3Builder.call(Maven3Builder.java:64)
    at hudson.remoting.UserRequest.perform(UserRequest.java:118)
    at hudson.remoting.UserRequest.perform(UserRequest.java:48)
    at hudson.remoting.Request$2.run(Request.java:326)
    at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
Caused by: org.apache.maven.plugin.MojoExecutionException: An error is occurred in the checkin process: Exception while executing SCM command.
    at org.apache.maven.plugins.release.PrepareReleaseMojo.prepareRelease(PrepareReleaseMojo.java:295)
    at org.apache.maven.plugins.release.PrepareReleaseMojo.execute(PrepareReleaseMojo.java:247)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
    ... 27 more
Caused by: org.apache.maven.shared.release.ReleaseExecutionException: An error is occurred in the checkin process: Exception while executing SCM command.
    at org.apache.maven.shared.release.phase.AbstractScmCommitPhase.checkin(AbstractScmCommitPhase.java:160)
    at org.apache.maven.shared.release.phase.AbstractScmCommitPhase.performCheckins(AbstractScmCommitPhase.java:145)
    at org.apache.maven.shared.release.phase.ScmCommitPreparationPhase.runLogic(ScmCommitPreparationPhase.java:76)
    at org.apache.maven.shared.release.phase.AbstractScmCommitPhase.execute(AbstractScmCommitPhase.java:78)
    at org.apache.maven.shared.release.DefaultReleaseManager.prepare(DefaultReleaseManager.java:234)
    at org.apache.maven.shared.release.DefaultReleaseManager.prepare(DefaultReleaseManager.java:169)
    at org.apache.maven.shared.release.DefaultReleaseManager.prepare(DefaultReleaseManager.java:146)
    at org.apache.maven.shared.release.DefaultReleaseManager.prepare(DefaultReleaseManager.java:107)
    at org.apache.maven.plugins.release.PrepareReleaseMojo.prepareRelease(PrepareReleaseMojo.java:291)
    ... 30 more
Caused by: org.apache.maven.scm.ScmException: Exception while executing SCM command.
    at org.apache.maven.scm.command.AbstractCommand.execute(AbstractCommand.java:63)
    at org.apache.maven.scm.provider.git.AbstractGitScmProvider.executeCommand(AbstractGitScmProvider.java:291)
    at org.apache.maven.scm.provider.git.AbstractGitScmProvider.checkin(AbstractGitScmProvider.java:217)
    at org.apache.maven.scm.provider.AbstractScmProvider.checkIn(AbstractScmProvider.java:410)
    at org.apache.maven.shared.release.phase.AbstractScmCommitPhase.checkin(AbstractScmCommitPhase.java:156)
    ... 38 more
Caused by: org.apache.maven.scm.ScmException: Detecting the current branch failed: fatal: ref HEAD is not a symbolic ref
    at org.apache.maven.scm.provider.git.gitexe.command.branch.GitBranchCommand.getCurrentBranch(GitBranchCommand.java:147)
    at org.apache.maven.scm.provider.git.gitexe.command.checkin.GitCheckInCommand.createPushCommandLine(GitCheckInCommand.java:192)
    at org.apache.maven.scm.provider.git.gitexe.command.checkin.GitCheckInCommand.executeCheckInCommand(GitCheckInCommand.java:132)
    at org.apache.maven.scm.command.checkin.AbstractCheckInCommand.executeCommand(AbstractCheckInCommand.java:54)
    at org.apache.maven.scm.command.AbstractCommand.execute(AbstractCommand.java:59)
    ... 42 more
channel stopped
Finished: FAILURE

The failing command and error message are:

[INFO] Executing: /bin/sh -c cd
/var/lib/jenkins/workspace/test_maven/parent && git symbolic-ref HEAD
[INFO]  Working directory:
/var/lib/jenkins/workspace/test_maven/parent  mojoFailed
org.apache.maven.plugins:maven-release-plugin:2.3.2(default-cli)
projectFailed ch.apkern.achilles:parent:1.0-SNAPSHOT  sessionEnded

I have figured out that the Jenkins Git plugin creates a detached HEAD ref "(no branch)" which causes the problem, I think. But I have absolutely no idea why this ref is created or how I can solve this problem.

I would be grateful for any help.

jenkins git
11 Answers

I had the same issue when trying to do a parametrized release build from a branch with maven-release-plugin:2.5.3 and maven-scm-provider-jgit:1.9.5.

I wanted to be able to select the branch for the "parametrized release build". This did not work and when I chose "Checkout/merge to local branch (optional)" it worked but I ended up with a branch "origin/origin/mybranch" in remote (repeated origin).

So:

  • Add "Git Parameter" to "This project is parameterized"
    Name: branch
    ParameterType: Branch
    Click Advanced:
    Branch Filter:origin/(.*)
    (this was the trick!)

  • Git Repository:
    Branches to build: refs/remotes/origin/${branch}

  • Additional Behaviors: -> Check out to specific local branch
    Branch Name: ${branch}

Have fun :-)

user_41184340

Most of answers above suggest to use Check out to specific local branch as the solution for the mentioned problem. Unfortunately it's not the best option because it will checkout to local branch manually defined in configuration of Pipeline.

Many times Jenkins is set to work in Multibranch Pipeline mode, what means that project can be built from different git branches.

In such solution remote branch doesn't match to local one.

Solution

The best and secure solution for these cases is to check out to matching local branch. F.ex. if pipeline is working on dev branch it will checkout to dev branch locally.

To accomplish such result, add additional property in Branch Sources section, named: Check out to matching local branch

user_38408840

If you're working with a pipeline script from SCM, here is the piece of syntax needed to achieve what is shown graphically in another answer:

extensions: [[$class: 'LocalBranch', localBranch: 'BRANCH_NAME']]

So for example if your remote branch is develop and you want to checkout a local branch also called develop to track that, then here is a minimal example to show the local branch extension in context:

checkout([$class: 'GitSCM', branches: [[name: '*/develop']], extensions: [[$class: 'LocalBranch', localBranch: 'develop']], userRemoteConfigs: [[credentialsId: 'xxx', url: 'yyy']]])

Where xxx and yyy would be replace by your own credentials ID and URL, respectively.

You can also generate the pipeline syntax yourself using the graphical syntax generator. See this answer.

user_51347220
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