Unable to update snapshots or run the install goal with Maven

Question

Does anyone have an idea how to resolve this Maven error? I get the following when I attempt to update my project's snapshots:

Build errors for my-projects-name; org.apache.maven.lifecycle.LifecycleExecutionException: Internal error in the plugin manager executing goal 'org.apache.maven.plugins:maven-dependency-plugin:2.0:unpack': Mojo execution failed.

And then when I try running "mvn install":

[INFO] [assembly:single {execution:default}] [INFO]   
--------------------------------------------------------- 
[ERROR] BUILD ERROR [INFO]
--------------------------------------------------------- 
[INFO] Error reading assemblies: No assembly descriptors found.

I'm running Maven 2.1.0. Can anyone shed some light as to why it's balking at me? Other team members are able to perform the above actions with the exact same copy of the code from SVN.

Thanks!

Edit: Here's the POM:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"&gt;
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>com.company.group</groupId>
    <artifactId>the-project-parent</artifactId>
    <version>1.0</version>
  </parent>
  <groupId>com.company.group.project</groupId>
  <artifactId>project-root</artifactId>
  <packaging>pom</packaging>
  <name>Project Name</name>
  <version>1.0.2-SNAPSHOT</version>
  <description>This artifact contains the common settings for the Project.</description>
  <url>http://maven.dev.companyName.com/sites/projectGroup/project&lt;/url&gt;
  <scm>
    <connection>scm:svn:https://sourceforge.companyname.com/svn/repos/group/tags/projGroup/my-project-name&lt;/connection&gt;
    <developerConnection>scm:svn:https://sourceforge.companyname.com/svn/repos/group/tags/projGroup/my-project-name&lt;/developerConnection&gt;
  </scm>
  <modules>
    <module>module-1</module>
    <module>module-2</module>
    <module>module-3</module>
    <module>module-4</module>
  </modules>
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>net.sourceforge.jtds.jdbc</groupId>
        <artifactId>jtds</artifactId>
        <version>1.2.2</version>
        <scope>runtime</scope>
      </dependency>
      <dependency>
        <groupId>org.unitils</groupId>
        <artifactId>unitils</artifactId>
        <version>2.2</version>
        <scope>test</scope>
      </dependency>
      <dependency>
        <groupId>org.easymock</groupId>
        <artifactId>easymock</artifactId>
        <version>2.3</version>
        <scope>test</scope>
      </dependency>

      <!-- I cut most dependencies for brevity -->

      <dependency>
        <groupId>taglibs</groupId>
        <artifactId>standard</artifactId>
        <version>1.1.2</version>
        <scope>runtime</scope>
        <exclusions>
          <exclusion>
            <artifactId>commons-logging</artifactId>
            <groupId>commons-logging</groupId>
          </exclusion>
        </exclusions>
      </dependency>
    </dependencies>
  </dependencyManagement>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-release-plugin</artifactId>
        <version>2.0-beta-5</version>
        <inherited>false</inherited>
        <configuration>
          <preparationGoals>clean install</preparationGoals>
          <tagBase>https://sourceforge.companyname.com/svn/repos/projects/tags/projGroup/my-project-name&lt;/tagBase&gt;
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

Answer 1

My recipe:

• Get rid of the <version> tags on <plugins>.
• run mvn --errors -U clean install. This wil tell maven to
  • Show errors in detail
  • Upgrade plugin versions
  • Cleanup everything, and install.
• In neither works... this is gonna hurt... delete the local repository and try again :(

Answer 2

I finally got it to run the install goal by downgrading Maven to 2.0.9.

EDIT: I tried executing mvn clean install and mvn clean install assembly:assembly using Maven 2.1.0 and it duplicated the above error: > "No Assembly descriptors found."

It still works with Maven 2.0.9. I'm wholly convinced that at minimum something has changed between versions which is causing this this discrepancy...

EDIT: From what I've been able to find out, it appears there's likely some kind of version conflict between Maven 2.1.0 and the version of this plugin we use:

<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-release-plugin</artifactId>
<version>2.0-beta-5</version>

Answer 3

You have no assembly plugin configuration shown in the pom you pasted. Perhaps it's in the parent? If there's no config then the assembly plugin will complain because you haven't configured it with a descriptor that tells it what to do. run mvn help:effective-pom and then paste those results (make sure to scrub any passwords) so I can see your full pom after inheritence.