Maven shade plugin isn't placing dependency class files into jar

My Maven project uses an external library as a dependency, com.sk89q.intake:intake, which I'm trying to package into my jar via the maven-shade-plugin. When building the project, the resulting jar does not contain any of the class files of com.sk89q.intake:intake. During the build process, I get this message, but the build continues on and succeeds:

[INFO] --- maven-shade-plugin:2.4.2:shade (default) @ EventManagerPlugin
[INFO] No artifact matching filter com.sk89q.intake:intake

Why is this happening? I'm able to download, access, and use the dependency in my project, so there shouldn't be anything wrong with naming of the artifact.

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>deletethis.eventmanager</groupId>
    <artifactId>EventManagerPlugin</artifactId>
    <version>1.0.0-beta1</version>
    <repositories>
        <repository>
            <id>spigot-repo</id>
            <url>https://hub.spigotmc.org/nexus/content/repositories/snapshots/</url>
        </repository>
        <repository>
            <id>maven.sk89q.com</id>
            <url>http://maven.sk89q.com/repo/</url>
        </repository>
    </repositories>
    <dependencies>
        <dependency>
           <groupId>org.spigotmc</groupId>
           <artifactId>spigot-api</artifactId>
           <version>1.8.8-R0.1-SNAPSHOT</version>
           <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.bukkit</groupId>
            <artifactId>bukkit</artifactId>
            <version>1.8.8-R0.1-SNAPSHOT</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>com.sk89q.intake</groupId>
            <artifactId>intake</artifactId>
            <version>4.2-SNAPSHOT</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.5</version>
                <configuration>
                    <archive>
                        <manifestEntries>
                            <Built-By>deletethis</Built-By>
                        </manifestEntries>
                    </archive>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>2.4.2</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <filters>
                                <filter>
                                    <artifact>com.sk89q.intake:intake</artifact>
                                    <includes>
                                        <include>com/sk89q/intake/**</include>
                                    </includes>
                                </filter>
                            </filters>
                            <relocations>
                                <relocation>
                                    <pattern>com.sk89q.intake</pattern>
                                    <shadedPattern>deletethis.eventmanager.lib.com.sk89q.intake</shadedPattern>
                                </relocation>
                            </relocations>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

As you can see, I am including the com.sk89q.intake:intake artifact. I have looked through the maven-shade-plugin documentation and don't see what I'm doing wrong. The naming is consistent with everything I have found online; that is, groupId:artifactId.

I have also tried building without the <relocation> class relocation tags to see if they were interfering.

It may be useful to know that I'm using M2Eclipse and building with the clean install goals.

Solution

The problem is that your are declaring the com.sk89q.intake:intake dependency with the provided scope.

Provided dependency are expected to be provided by the container at runtime so the maven-shade-plugin will not add it to your shaded jar. As such, you need to remove the provided scope from the dependency declaration:

<dependency>
    <groupId>com.sk89q.intake</groupId>
    <artifactId>intake</artifactId>
    <version>4.2-SNAPSHOT</version>
</dependency>

Relevant build log after this change:

[INFO] --- maven-shade-plugin:2.4.2:shade (default) @ test ---
[INFO] Including com.sk89q.intake:intake:jar:4.2-SNAPSHOT in the shaded jar.
[INFO] Including com.google.guava:guava:jar:18.0 in the shaded jar.
[INFO] Including com.google.code.findbugs:jsr305:jar:3.0.0 in the shaded jar.