[jira] Closed: (MASSEMBLY-420) maven fails when packing parent pom

["John Casey (JIRA)" <ji...@codehaus.org>]

     [ http://jira.codehaus.org/browse/MASSEMBLY-420?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

John Casey closed MASSEMBLY-420.
--------------------------------

       Resolution: Fixed
    Fix Version/s: 2.2-beta-6
         Assignee: John Casey

Creating empty archives was never part of the design of the assembly plugin; it was a bug in the plexus-archiver at one point.

If the assembly contains no files, by design it should fail to alert the user that something has gone wrong. It's not considered sane to create a distribution archive that contains nothing.

For a more detailed discussion about building an assembly at the parent level, see: http://maven.apache.org/plugins/maven-assembly-plugin/faq.html#module-binaries

and: http://maven.apache.org/plugins/maven-assembly-plugin/examples/multimodule/module-binary-inclusion-simple.html


NOTE: Those pages are both in dire need of updating. I've made the changes, but will wait to push the new site until the release of this plugin.

So, until that release, those pages will give BAD ADVICE on this topic.

Here is the gist:

{noformat}
        <p><b>If your assembly includes module binaries, those binaries won't be available to the assembly plugin except in special cases.</b> This is normally seen
           when the Assembly Plugin is bound to a phase of the standard build lifecycle in the <b>parent POM</b> of a multimodule build.
           It is a result of the way Maven sorts and executes the build process for a multimodule project layout.
        </p>
        <p>In a multimodule hierarchy, when a child module declares the parent POM in its &lt;parent/&gt; section, Maven interprets this to mean that the parent
           project's build must be completed before the child build can start. This ensures that the parent project is in its final form by the time the child
           needs access to its POM information. In cases where the Assembly Plugin is included as part of that parent project's build process, it will execute
           along with everything else as part of the parent build - <b>before the child build can start</b>. If the assembly descriptor used in that parent build
           references module binaries, it effectively expects the child build to be completed <b>before the assembly is processed</b>. This leads to a recursive
           dependency situation, where the child build depends on the parent build to complete before it can start, while the parent build depends on the presence
           of child-module artifacts to complete successfully. Since these artifacts are missing, the Assembly Plugin will complain about missing artifacts, and
           the build will fail.
        </p>
        <p>In many cases, you can avoid this problem by adding a new child module whose sole purpose is to produce your assembly. In the POM for this new project,
           add dependency definitions for any of the module binaries you had previously referenced. This will ensure the new assembly child is built last.
           Then, move your assembly descriptor into this new child module. At this point, you have the option of either changing all moduleSet/binaries references 
           to dependencySet references, <b>or you can keep the moduleSets and instead set the useAllReactorProjects flag to <i>true</i> for each moduleSet.</b>
        </p>
        <p>
           Obviously, any fileSet or file references you may have in this descriptor may need
           to be adjusted or have the files they reference moved into the new child module alongside the descriptor itself.
        </p>
        <p>In cases where you absolutely must use module-binaries references, you should create an assembly-child POM mentioned above, then insert
           <code>&lt;useAllReactorProjects&gt;true&lt;useAllReactorProjects&gt;</code> to each of your <code>moduleSet</code> sections. Then, bind the assembly
           in your assembly-child POM (normally to the <code>package</code> phase) using the <code>single</code> goal. When you execute the build from the top-level POM,
           Maven should generated your assembly in the new child project.
        </p>
        <p><b>NOTE:</b> The useAllReactorProjects flag is only available in version 2.2-beta-6 and higher.</p>
{noformat}

> maven fails when packing parent pom
> -----------------------------------
>
>                 Key: MASSEMBLY-420
>                 URL: http://jira.codehaus.org/browse/MASSEMBLY-420
>             Project: Maven 2.x Assembly Plugin
>          Issue Type: Bug
>    Affects Versions: 2.2-beta-3
>         Environment: Windows Vista
>            Reporter: Karsten Ohme
>            Assignee: John Casey
>            Priority: Blocker
>             Fix For: 2.2-beta-6
>
>
> I have a parent module and multiple sub modules. I must build all submodules manually, because the parent assembly cannot be created.
> I have defined the assembly plugin in the parent.
> [INFO] [assembly:single {execution: make-assembly}]
> [WARNING] Cannot include project artifact: org.foo.bar:j2se:pom:1
> .0.2-SNAPSHOT; it doesn't have an associated file or directory.
> [INFO]
> ------------------------------------------------------------------------
> [ERROR] BUILD ERROR
> [INFO]
> ------------------------------------------------------------------------
> [INFO] Failed to create assembly: Error creating assembly archive
> jar-with-dependencies: You must set at least one file.
> In previous releases it was working.

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