Is the issue related to the fact that I have
${ced2ar.version} in the parent pom, even though
${ced2ar.version} appears correctly defined in further
down in the file?
No, the problem comes from the way which you declared the child modules.
Here is an extract of the rdb module pom.
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>ced2ar3-rdb-parent</artifactId>
<groupId>edu.cornell.ncrn.ced2ar</groupId>
<version>${ced2ar.version}</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>ced2ar3-rdb</artifactId>
</project>
The ${ced2ar.version} property defined in the parent version of the child project cannot be resolved without building the reactor project that first builds the parent pom that defines this property. That's why your build works in development (with the reactor) but doesn't work without it.
To solve your issue you could use the revision standard property with the flatten-maven-plugin that will help you to set a unique version between the parent and the child.
Your reactor pom could look like :
<project>
<modelVersion>4.0.0</modelVersion>
<groupId>my-group</groupId>
<artifactId>my-parent</artifactId>
<version>${revision}</version>
...
<properties>
<revision>1.0.0</revision>
</properties>
<modules>
<module>rdb</module>
<module>rdb-tests</module>
..
</modules>
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>flatten-maven-plugin</artifactId>
<version>1.0.0</version>
<configuration>
<updatePomFile>true</updatePomFile>
</configuration>
<executions>
<execution>
<id>flatten</id>
<phase>process-resources</phase>
<goals>
<goal>flatten</goal>
</goals>
</execution>
<execution>
<id>flatten.clean</id>
<phase>clean</phase>
<goals>
<goal>clean</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
And the rdb pom.xml for example like that :
<project>
<parent>
<groupId>my-group</groupId>
<artifactId>my-parent</artifactId>
<version>${revision}</version>
</parent>
<artifactId>rdb</artifactId>
...
</project>
About your comment :
I get an invalid POM error with: "Project name missing, Project
description missing, Project URL missing, SCM URL missing, Developer
information missing". Indeed, after inspecting the generated
.flattened-pom.xml, I do not see these fields
it is expected as the flattened plugin strips some metadata of the original POM :
The flattened POM is a reduced version of the original POM with the
focus to contain only the important information for consuming it.
Therefore information that is only required for maintenance by
developers and to build the project artifact(s) are stripped. Starting
from here we specify how the flattened POM is created from the
original POM and its project
But you can override this default by adding the elements that you don't want to strip in the pomElements parameter of the plugin.
For example :
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>flatten-maven-plugin</artifactId>
<version>1.0.0</version>
<configuration>
<updatePomFile>true</updatePomFile>
<pomElements>
<name/>
<description/>
<developers/>
<contributors/>
<url/>
<scm/>
</pomElements>
</configuration>
<executions>
<execution>
<id>flatten</id>
<phase>process-resources</phase>
<goals>
<goal>flatten</goal>
</goals>
</execution>
<execution>
<id>flatten.clean</id>
<phase>clean</phase>
<goals>
<goal>clean</goal>
</goals>
</execution>
</executions>
</plugin>
