Eclipse and Tycho - ${tycho-version}

Looking at Tycho tutorials and answers here at Stackoverflow a lot of then contain the variable ${tycho-version} example:

<plugin>
    <groupId>org.eclipse.tycho</groupId>
    <artifactId>tycho-maven-plugin</artifactId>
    <version>${tycho-version}</version>
    <extensions>true</extensions>
</plugin>

What is nowhere described is who is responsible for resolving this variable. Is it done automatically by Eclipse/M2Eclipse plugin or does this variable means the developer is responsible for specifying the version?

If the developer is responsible where to get the list of versions?

Solution

This is a standard idiom for ensuring all Tycho plug-ins are from the same version: if plug-ins from multiple versions clash, it can result in very hard to debug issues. If this is the only place you enter a tycho version, this might seem unnecessary, but if you have to provide configuration for multiple elements, this will be responsible.

In other words, the build configuration should include a value for this property (or it should be set via the -D property syntax, e.g. mvn clean install -Dtycho-version=1.0.0).

In order to find out the possible versions, you could execute a search on maven central; where you can see the latest version as of today (3rd Apr, 2017) is 1.0.0.