Question

After a long search for a JavaScript compressor I could use in Maven, I finally found one:

        <plugin>
            <groupId>net.alchim31.maven</groupId>
            <artifactId>yuicompressor-maven-plugin</artifactId>
            <version>1.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>compress</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <jswarn>false</jswarn>
            </configuration>
        </plugin>

Now in the latest version of m2e in Eclipse, I get the following error:

Plugin execution not covered by lifecycle configuration: net.alchim31.maven:yuicompressor-maven-plugin:1.1:compress (execution: default, phase: process-resources)

Lovely. I don’t get it—it’s just a plugin. Why can’t m2e simply call any old plugin I have? What’s wrong with this one? How do I fix this?

Answer 1

See http://wiki.eclipse.org/M2E_plugin_execution_not_covered

To solve some long-standing issues,
m2e 1.0 requires explicit instructions
what to do with all Maven plugins
bound to “interesting” phases (see M2E
interesting lifecycle phases) of
project build lifecycle. We call these
instructions “project build lifecycle
mapping” or simply “lifecycle mapping”
because they define how m2e maps
information from project pom.xml file
to Eclipse workspace project
configuration and behaviour during
Eclipse workspace build.

Project build lifecycle mapping
configuration can be specified in
project pom.xml, contributed by
Eclipse plugins and there is also
default configuration for some
commonly used Maven plugins shipped
with m2e. We call these “lifecycle
mapping metadata sources”. m2e will
create error marker like below for all
plugin executions that do not have
lifecycle mapping in any of the
mapping metadata sources.

Plugin execution not covered by lifecycle configuration:
org.apache.maven.plugins:maven-antrun-plugin:1.3:run
   (execution: generate-sources-input, phase: generate-sources)

m2e matches plugin
executions to actions using
combination of plugin groupId,
artifactId, version range and goal.
There are three basic actions that m2e
can be instructed to do with a plugin
execution — ignore, execute and
delegate to a project configurator.