[MASSEMBLY-787] Using Component Descriptor

**[Karl Heinz Marbaise](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=khmarbaise)** opened **[MASSEMBLY-787](https://issues.apache.org/jira/browse/MASSEMBLY-787?redirect=false)** and commented

I have defined a shared descriptor using a separate module as described in the documentation.
This shared descriptor is used by maven assembly-plugin via `` which it self contains a componentDescriptor.

This unfortunately fails during the running the build with the message:

```
00:00:38.206 [ERROR] Failed to execute goal org.apache.maven.plugins:maven-assembly-plugin:2.5.5:single (anton-1) on project p1: Error reading assemblies: Failed to locate component descriptor: assemblies/subfolder-component -> [Help 1]
00:00:38.207 [ERROR] Failed to execute goal org.apache.maven.plugins:maven-assembly-plugin:2.5.5:single (anton-2) on project p2: Error reading assemblies: Failed to locate component descriptor: assemblies/subfolder-component -> [Help 1]
00:00:38.207 [ERROR] Failed to execute goal org.apache.maven.plugins:maven-assembly-plugin:2.5.5:single (anton-3) on project p3: Error reading assemblies: Failed to locate component descriptor: assemblies/subfolder-component -> [Help 1]
00:00:38.208 [ERROR] Failed to execute goal org.apache.maven.plugins:maven-assembly-plugin:2.5.5:single (anton-4) on project p4: Error reading assemblies: Failed to locate component descriptor: assemblies/subfolder-component -> [Help 1]
```

This looks like the resolution of the component descriptor via classpath does not work correctly. I have also tested to use the component descriptor with the "assemblies/" prefix.

```xml
env

tar

false

subfolder-component



${project.build.directory}/output/META-INF
unix
./
0755
0644

MANIFEST.MF


....
```

---

**Affects:** 2.5.5

Reproduce the Maven assembly-plugin 2.5.5 build using a shared descriptor, a , and the subfolder-component component descriptor shown in the issue. Start by tracing component descriptor resolution through the classpath and compare the failing path with the documented assemblies/ prefix. Done means the shared descriptor resolves its component descriptor and the affected projects build successfully.

Written by the indexing model from the issue text.