title: Understanding Tycho error compilation: Missing requirement
body: <p>I'm compiling a eclipse based product with tycho and i'm having an error compilation that i don't know how to resolve. </p>
  
  <p>My error code is: </p>
  
  <pre><code>[ERROR] Cannot resolve project dependencies:
  [ERROR]   Software being installed: eu.geeking.gds.feature.group 1.0.0.qualifier
  [ERROR]   Missing requirement: eu.geeking.gds.feature.group 1.0.0.qualifier requires 'org.eclipse.equinox.p2.iu; dev.geeking.gds.toolchain.cortexm 0.0.0' but it could not be found
  </code></pre>
  
  <p>In <a href="https://wiki.eclipse.org/Tycho/Dependency_Resolution_Troubleshooting" rel="nofollow noreferrer">https://wiki.eclipse.org/Tycho/Dependency_Resolution_Troubleshooting</a> says next: </p>
  
  <pre><code> Missing requirement: &lt;artifact&gt; requires '&lt;dependency&gt;' but it could not be found.
  
   This line prints one of the mandatory dependencies which cannot be resolved. This can either be a dependency of the seed artifact, or a dependency of an artifact which is a direct or transitive dependency of the seed artifact. See below for details on the &lt;dependency&gt; part of the message.
  </code></pre>
  
  <p>but my message is  </p>
  
  <pre><code>"Missing requirement: &lt;artifact&gt; requires '&lt;dependency&gt;'; &lt;plugin-name&gt; but it could not be found."
  </code></pre>
  
  <p>I understand that plugin 'dev.geeking.gds.toolchain.cortexm' needs 'org.eclipse.equinox.p2.iu' dependency but i can't find it. I have written 'dev.geeking.gds.toolchain.cortexm' plugin and i don't have any error about 'org.eclipse.equinox.p2.iu' in eclipse and i don't know how to fix it.</p>