Java – buildnumber-maven-plugin got svn: Authentication required for ‘Subversion Repository’ error

The buildnumber-maven-plugin is pretty darn quirky, which is probably why it's still a beta. The format is only for those items you wish to apply a Java message format to and in most cases, it only useful with timestamps and literal strings. If you don't need a timestamp don't use the format option when getting the Subversion revision number. If you use the format, then like you indicated, it'll give you a build number that always increments by one rather than the SCM version number.

If you do need the timestamp or have other items your deriving from the buildnumber plugin as well as the Subversion revision, do each one as a separate executions. Here's an example of how to get the Subverison revision number and the build timestamp using two separate executions of the plugin:

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>buildnumber-maven-plugin</artifactId>
    <version>1.0-beta-4</version>
    <executions>
        <execution>
            <id>generate-buildnumber</id>
                <phase>validate</phase>
            <goals>
                <goal>create</goal>
            </goals>
            <configuration>
                <useLastCommittedRevision>true</useLastCommittedRevision>
                <buildNumberPropertyName>buildRevision</buildNumberPropertyName>
            </configuration>
        </execution>
        <execution>
            <id>generate-timestamp</id>
            <phase>validate</phase>
            <goals>
                <goal>create</goal>
            </goals>
            <configuration>
                <format>{0,date,yyyy-MM-dd HH:mm:ss}</format>
                <items>
                    <item>timestamp</item>
                </items>
                <buildNumberPropertyName>buildDateTime</buildNumberPropertyName>
            </configuration>
        </execution>
    </executions>
</plugin>

The key to making this work is using the buildNumberPropertyName element. Checkout the plugin's Usage page for more information about the usefulness of the Java message format is for.

In my case of a similar problem, instead of using Andrew's suggestion for the fix, it worked simply after I introduced <pluginManagement> tag to the pom.xml in question. Looks like that error is due to a missing <pluginManagement> tag. So, in order to avoid the exceptions in Eclipse, one needs to simply enclose all the plugin tags inside a <pluginManagement> tag, like so:

<build>
    <pluginManagement>
        <plugins>
            <plugin> ... </plugin>
            <plugin> ... </plugin>
                  ....
        </plugins>
    </pluginManagement>
</build>

Once this structure is in place, the error goes away.