我正在使用mercurial，maven和maven-release-plugin来发布。在执行任务release:prepare时，它失败并显示以下堆栈跟踪：
[INFO] Transforming 'producer'...
[INFO] Not removing release POMs
[INFO] Checking in modified POMs...
[INFO] EXECUTING: /bin/sh -c cd /home/dir/producer && hg branch
[DEBUG] version-1.1
[INFO] EXECUTING: /bin/sh -c cd /home/dir/producer && hg outgoing
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2:16.923s
[INFO] Finished at: Tue Jun 30 16:00:45 MSK 2015
[INFO] Final Memory: 10M/207M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-release-plugin:2.5:prepare (default-cli) on project producer: An error is occurred in the checkin process: Exception while executing SCM command. NullPointerException -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-release-plugin:2.5:prepare (default-cli) on project producer: 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.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
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:281)
at org.apache.maven.plugins.release.PrepareReleaseMojo.execute(PrepareReleaseMojo.java:232)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
... 19 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.ScmCommitDevelopmentPhase.runLogic(ScmCommitDevelopmentPhase.java:91)
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:277)
... 22 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.hg.HgScmProvider.checkin(HgScmProvider.java:223)
at org.apache.maven.scm.provider.AbstractScmProvider.checkIn(AbstractScmProvider.java:415)
at org.apache.maven.shared.release.phase.AbstractScmCommitPhase.checkin(AbstractScmCommitPhase.java:156)
... 30 more
Caused by: java.lang.NullPointerException
at org.apache.maven.scm.provider.hg.HgUtils.differentOutgoingBranchFound(HgUtils.java:313)
at org.apache.maven.scm.provider.hg.command.checkin.HgCheckInCommand.executeCheckInCommand(HgCheckInCommand.java:66)
at org.apache.maven.scm.command.checkin.AbstractCheckInCommand.executeCommand(AbstractCheckInCommand.java:54)
at org.apache.maven.scm.command.AbstractCommand.execute(AbstractCommand.java:59)
... 33 more
[ERROR]
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
跑完后：
mvn -X clean release:prepare
maven-release-plugin版本：
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-release-plugin</artifactId>
<version>2.5</version>
我花了几个小时..发现与我的情况无关，完全陷入困境。看起来它无法执行hg传出，但在失败后我可以执行hg传出而没有任何问题。
更奇怪的是我可以使用相同的hg和mvn版本在另一台机器上成功运行它。
我找到的唯一区别是，在第一个框中我有Ubuntu 12.04.5 LTS，第二个Ubuntu 12.04.3 LTS。这是Ubuntu 12.04.5的问题吗？希望不是。但那就太奇怪了。