Why eclipse does not find my features? - eclipse

Question

I have written some eclipse plugins and consolidated them in featues. If the features does only contain plugins all is ok. But if I include a feature to a feature then I get the following error:
Unable to find feature "<featureName>" with version in range [2.6.0,2.6.1).
where featuerName is the including feature. I tinkered with the version numbers of the included feature without success.
here comes the including feature.xml
<?xml version="1.0" encoding="UTF-8"?>
<feature
id="de.mdsd.xtext.support.validator.model.sdk"
label="Xtext Support Validator Generator Feature"
version="2.6.0.qualifier"
provider-name="XXX Software">
<description>
This plugin provides a small DSL for describing and generating an Xtext validator class.
</description>
<includes
id="de.mdsd.xtext.support.sdk.sdk"
version="[2.6.1,3.0.0)"/>
<requires>
<import plugin="org.eclipse.xtext"/>
<import plugin="org.eclipse.equinox.common" version="3.5.0" match="greaterOrEqual"/>
<import plugin="org.eclipse.emf.codegen.ecore" version="2.10.2" match="greaterOrEqual"/>
<import plugin="de.mdsd.xtext.swtch.model" version="2.0.0" match="greaterOrEqual"/>
<import plugin="org.eclipse.xtext.util"/>
<import plugin="org.eclipse.emf.ecore"/>
<import plugin="org.eclipse.emf.common"/>
<import plugin="org.eclipse.xtext.xbase.lib"/>
<import plugin="org.antlr.runtime"/>
<import plugin="org.eclipse.xtext.common.types"/>
<import plugin="org.apache.log4j"/>
<import plugin="org.eclipse.xtext.ui"/>
<import plugin="org.eclipse.ui.editors" version="3.5.0" match="greaterOrEqual"/>
<import plugin="org.eclipse.ui.ide" version="3.5.0" match="greaterOrEqual"/>
<import plugin="org.eclipse.xtext.ui.shared"/>
<import plugin="org.eclipse.ui"/>
<import plugin="org.eclipse.xtext.builder"/>
<import plugin="org.eclipse.xtext.common.types.ui"/>
<import plugin="org.eclipse.xtext.ui.codetemplates.ui"/>
<import plugin="org.eclipse.compare"/>
<import plugin="de.mdsd.xtext.support.sdk" version="2.1.0" match="greaterOrEqual"/>
<import plugin="de.mdsd.xtext.up.name.providerswitch.model" version="1.4.0" match="greaterOrEqual"/>
</requires>
<plugin
id="de.mdsd.xtext.support.validator.model"
download-size="0"
install-size="0"
version="0.0.0"
unpack="false"/>
<plugin
id="de.mdsd.xtext.support.validator.model.ui"
download-size="0"
install-size="0"
version="0.0.0"
unpack="false"/>
</feature>
here comes the included feature.xml
<?xml version="1.0" encoding="UTF-8"?>
<feature
id="de.mdsd.xtext.support.sdk.sdk"
label="Xtext Support Feature"
version="2.6.1.qualifier"
provider-name="MDSD Software">
<description url="http://www.example.com/description">
This is a collection of classes that support the development
of Xtext generated tools.
Now it contains switches and name providers for GenModel-, Ecore models and Xtext grammars.
</description>
<copyright url="http://www.example.com/copyright">
Copyright Olaf Bigalk 2013
</copyright>
<license url="http://www.example.com/license">
EPL
</license>
<requires>
<import plugin="org.eclipse.emf.ecore" version="2.9.0" match="greaterOrEqual"/>
<import plugin="org.eclipse.xtext" version="2.4.2" match="greaterOrEqual"/>
<import plugin="org.eclipse.xtend.lib"/>
<import plugin="com.google.guava"/>
<import plugin="org.eclipse.xtext.xbase.lib"/>
<import plugin="org.eclipse.emf.codegen.ecore"/>
<import plugin="org.eclipse.xtext.ui" version="2.4.3" match="greaterOrEqual"/>
<import plugin="org.eclipse.jdt.core" version="3.9.0" match="greaterOrEqual"/>
<import plugin="org.eclipse.xtend.typesystem.emf" version="1.4.0" match="greaterOrEqual"/>
<import plugin="org.eclipse.xtext.xbase" version="2.8.3" match="greaterOrEqual"/>
<import plugin="org.eclipse.emf" version="2.6.0" match="greaterOrEqual"/>
</requires>
<plugin
id="de.mdsd.xtext.support.sdk"
download-size="0"
install-size="0"
version=""
unpack="false"/>
<plugin
id="de.mdsd.xtext.support.xtend.utils"
download-size="0"
install-size="0"
version=""
unpack="false"/>
<plugin
id="de.mdsd.xtext.support.xbase.utils"
download-size="0"
install-size="0"
version=""
unpack="false"/>
<plugin
id="de.mdsd.xtext.support.utils"
download-size="0"
install-size="0"
version=""
unpack="false"/>
</feature>
What is the reason for this error ?

Answer 1

You can't use a version range like [2.6.1,3.0.0) in the includes element of a feature.xml.
Either specify the exact version of the feature to be included (2.6.1.qualifier) or specify 0.0.0 to not check the version.