Support of git worktree option (for JGIT)

[qboileau]

Hi, since git 2.5.0 worktree option allow to create many working tree linked to a single repository.

Building a linked working tree using git-commit-id-plugin mojo failed because current git reference can't be retrieve. Seems to be JGit issue, but I think it's useful to report here first.

Build exception :

[INFO] --- git-commit-id-plugin:2.1.15:revision (default)  ---
org.apache.maven.plugin.MojoExecutionException: Could not get HEAD Ref, are you sure you have some commits in the dotGitDirectory?
    at pl.project13.maven.git.JGitProvider.prepareGitToExtractMoreDetailedReproInformation(JGitProvider.java:106)
    at pl.project13.maven.git.GitDataProvider.loadGitData(GitDataProvider.java:98)
    at pl.project13.maven.git.GitCommitIdMojo.loadGitDataWithJGit(GitCommitIdMojo.java:585)
    at pl.project13.maven.git.GitCommitIdMojo.loadGitData(GitCommitIdMojo.java:558)
    at pl.project13.maven.git.GitCommitIdMojo.execute(GitCommitIdMojo.java:376)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
    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:116)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
    at org.apache.maven.cli.MavenCli.execute(MavenCli.java:862)
    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:286)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:197)
    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:289)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)

[TheSnoozer]

Hi,
yes this seems not yet implemented in the jGit Implementation.
Does it fail as well when you use the native git binary?

Recently started discussion on eclipse about the "worktree"
https://www.eclipse.org/forums/index.php/m/1703524/
Couldn't find a feature-request on the bug-list yet:
https://bugs.eclipse.org/bugs/buglist.cgi?quicksearch=worktree
(maybe we should file one?)

Also it should be worth quoting from here https://github.com/blog/2042-git-2-5-including-multiple-worktrees-and-triangular-workflows:

Please note that the worktree feature is experimental. It may have some bugs, and its interface may change based on user feedback. It's not recommended to use git worktree with a repository that contains submodules.

Is it still experimental? if so we still have a bit time to implement ;-)

[TheSnoozer]

see: https://bugs.eclipse.org/bugs/show_bug.cgi?id=477475

[athrunsun]

@qboileau @TheSnoozer Now it is 2017 and git comes to version 2.12.x, but I am still having issue with git-commit-id-plugin:2.2.2, that when I tried to build a maven project under a git worktree, it gave me:

[ERROR] Failed to execute goal pl.project13.maven:git-commit-id-plugin:2.2.2:revision (default) on project <some_project>: Could not complete Mojo execution... Error: Could not get
HEAD Ref, are you sure you have some commits in the dotGitDirectory? -> [Help 1]

Could you help me please?

[TheSnoozer]

Would be happy to have this in this plugin as well, but as outlined its a JGit issue (a library we use inside the plugin). If the library doesn't support it, this plugin doesn't support it either.

The Bug 7 Enhancement request for JGit (https://bugs.eclipse.org/bugs/show_bug.cgi?id=477475) is still open and thus it is not available afaik.

[TheSnoozer]

Note: This feature will prop break java jdk 1.7 support.

With jgit v4.6 the build was moved towards 1.8 only (https://bugs.eclipse.org/bugs/show_bug.cgi?id=500059)

[TheSnoozer]

Well sometimes third party libs takes ages...the bug /enhancement request for JGit (https://bugs.eclipse.org/bugs/show_bug.cgi?id=477475) is still open and thus it is not available for jgit...just saying if it isn't obvious....the native git-implementation (<useNativeGit>true</useNativeGit>) should support this

[athrunsun]

@TheSnoozer That's sad... But on the other hand I can at least skip execution of this plugin from now on when I am on a git worktree since Added property to skip from CLI is released in 2.2.3.

[TheSnoozer]

@athrunsun agree this is kinda annoying...
For skipping from CLI please checkout this issue:
#315

In a nutshell you can't skip by command-line when the property is configured as plugin configuration (a maven bug). The workaround that even was suggested by the maven team is outlined in #315 (comment)
Regardless I fixed this properly and this workaround won't be required in 2.2.4.

[athrunsun]

@TheSnoozer That sounds really great, thanks for the fix! Looking forward to 2.2.4 release.

[lysium]

FWIW, I still get the error with 2.2.4:

[ERROR] Failed to execute goal pl.project13.maven:git-commit-id-plugin:2.2.4:revision (default) on project system-activation-service-app: Could not complete Mojo execution...: Error: Could not get HEAD Ref, are you sure you have some commits in the dotGitDirectory? -> [Help 1]

Or am doing sth. wrong?

The workaround with adding -Dmaven.gitcommitid.skip=true works, though.