Properties not removed after running recipe RemoveRedundantDependencyVersions

[wesboe]

What problem are you trying to solve?

The RemoveRedundantDependencyVersions recipes removes redundant version of dependencies. But when the version is a property, the property is not removed.
Impact
Unused properties in your pom.xml or you override the property of a parent pom.
For example Spring Boot has Managed Dependency Coordinates in their parent pom spring-boot-dependencies.

What precondition(s) should be checked before applying this recipe?

We can limit the execution to Maven.

Describe the situation before applying the recipe

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.3.2</version>
    </parent>

    <artifactId>example</artifactId>

    <properties>
        <logback.version>1.4.7</logback.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
</project>

Describe the situation after applying the recipe

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.3.2</version>
    </parent>

    <artifactId>example</artifactId>

    <properties>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
</project>

Have you considered any alternatives or workarounds?

For the properties managed by Spring Boot you can use the recipe to remove a property tag and add all properties managed by Spring Boot.

Any additional context

Are you interested in contributing this recipe to OpenRewrite?

Yes I would like to contribute

[timtebeek]

Thanks for logging an issue @wesboe ! I'm doubting between whether this should be a standalone recipe or whether it should be part of RemoveRedundantDependencyVersions. Note that RemoveRedundantDependencyVersions could also call a separate recipe to clean up properties used in removed dependency version tags.

Either way the tricky part is knowing if a property really isn't used anymore. It could still be referenced elsewhere in the same pom.xml, or in a parent or child pom.xml file. Any thoughts as to how you had wanted to cover such cases? Perhaps at first only removing property versions that are also present in a parent to minimize disruption?

[HelloDhero]

I think if this is deleted, it will bring many side effects