Consumer POM flattening behavior for profiles in Maven 4?

[Jeremy Norris <je...@lbnetworks.co>]

Hi,

What is the intended behavior of consumer POM flattening behavior in terms of profiles?
We have noticed in local testing that it can leave behind no-op profiles in a consumer POM instead of removing them entirely (as we would have anticipated).

For example, with a POM such as this:

```xml
<?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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>foo</groupId>
  <artifactId>bar</artifactId>
  <version>1.0.0-SNAPSHOT</version>
  <packaging>jar</packaging>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
  </properties>
  <profiles>
    <profile>
      <id>lint</id>
      <activation>
        <jdk>[21,)</jdk>
      </activation>
      <build>
        <plugins>
          <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
              <compilerArgs>
                <arg>-Xlint:all</arg>
              </compilerArgs>
            </configuration>
          </plugin>
        </plugins>
      </build>
    </profile>
  </profiles>
</project>
```

We end up with a flattened consumer POM containing a no-op profile like this:

```xml
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>foo</groupId>
  <artifactId>bar</artifactId>
  <version>1.0.0-SNAPSHOT</version>
  <profiles>
    <profile>
      <id>lint</id>
      <activation>
        <jdk>[21,)</jdk>
      </activation>
    </profile>
  </profiles>
```

Is it intended to leave behind no-op profiles such as this in consumer POM’s when flattened?


Thanks,
Jeremy