Does requireProperty not require a typical maven property in maven enforcer? - maven

Question

I am trying to require that a particular property is defined during the build using the maven enforcer plugin and the RequireProperty rule.
The relevant part of my pom.xml is this.
<?xml version="1.0" encoding="UTF-8"?>
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>test</groupId>
<artifactId>test</artifactId>
<version>1.0.0</version>
<packaging>jar</packaging>
<properties>
<foo>bar</foo>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-enforcer-plugin</artifactId>
<version>3.0.0-M1</version>
<executions>
<execution>
<id>require-properties</id>
<goals><goal>enforce</goal></goals>
<configuration>
<rules>
<requireProperty>
<property>${foo}</property>
<message>foo must be defined -${foo}-</message>
</requireProperty>
</rules>
<!-- Disabling, since it seems to not notice properties that are defined -->
<!-- <skip>true</skip> -->
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
When I run this, the enforcer rule fails.
$ mvn install
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------------------< test:test >------------------------------
[INFO] Building test 1.0.0
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-enforcer-plugin:3.0.0-M1:enforce (require-properties) # test ---
[WARNING] Rule 0: org.apache.maven.plugins.enforcer.RequireProperty failed with message:
foo must be defined -bar-
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.398 s
[INFO] Finished at: 2019-03-15T11:45:58-04:00
[INFO] ------------------------------------------------------------------------
It also fails if I define it on the command line.
$ mvn install -Dfoo=quz
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------------------< test:test >------------------------------
[INFO] Building test 1.0.0
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-enforcer-plugin:3.0.0-M1:enforce (require-properties) # test ---
[WARNING] Rule 0: org.apache.maven.plugins.enforcer.RequireProperty failed with message:
foo must be defined -quz-
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
Is this rule not for <properties> values? From the message, it is clear that the value is actually set.
I also tried adding <regex>.*</regex> with no effect.
How to I check that a maven property is set?
Real case details
In the example, the property is defined in the pom, so it sort of redundant to include the check. In the real case, the plugin is defined in the parent pom and the property is defined in the leaf pom. The behavior is the same in the real case.
mvn -version
Apache Maven 3.6.0 (97c98ec64a1fdfee7767ce5ffb20918da4f719f3; 2018-10-24T14:41:47-04:00)
Maven home: /usr/local/Cellar/maven/3.6.0/libexec
Java version: 10.0.1, vendor: Oracle Corporation, runtime: /Library/Java/JavaVirtualMachines/jdk-10.0.1.jdk/Contents/Home
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "10.14.3", arch: "x86_64", family: "mac"