Coursier ignores overridden properties in child POM

[ppkarwasz]

In the Apache Log4j project we support multiple versions of the same library (in different Maven modules).

In order to do that, in the parent POM we specify the version of the library via a Maven property:

<properties>
  <slf4j.version>2.0.9</slf4j.version>
</properties>
<dependencyManagement>
  <dependencies>
      <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>${slf4j.version}</version>
      </dependency>
  </dependencies>
</dependencyManagement>

and we overwrite the property value in the child POM:

<properties>
  <slf4j.version>1.7.25</slf4j.version>
</properties>

This works very well with Maven, since the "inheritance assembly" phase precedes the "model interpolation" phase (cf. Maven Model Builder).

However, as reported by one of our users (cf. apache/logging-log4j2#2065) this doesn't work with Coursier: in the above example Maven with choose version 1.7.25 while Coursier will choose version 2.0.9.

[gatisnolv]

I think you meant that you specify <slf4j.version>2.0.9</slf4j.version> and not <slf4j.api>2.0.9</slf4j.api> in the Parent POM, so in your redacted example:

<properties>
  <slf4j.version>2.0.9</slf4j.version>
</properties>
<dependencyManagement>
...

Links to the referenced pom files for easy access:

• Parent pom
• Child pom

I created a minimal example to reproduce this and the steps are almost the same as what I described for this other issue I reported earlier, but I include them below as well.
Similarly to that other issue, I want to point out that since this is the behavior irrespective of whether the parent or child project has a higher version, it is clear that this is NOT an example of the difference in version handling between Coursier and Maven (latest-wins vs nearest-wins), but a separate issue.

Setup: Maven 3.9.0, Coursier 2.1.8
Note: I couldn't figure out how to directly run cs resolve against the local Maven repository, so to serve it on localhost, from ~/.m2/repository run something like npx http-server (or whatever web server you prefer), making it available on http://localhost:8080/

Minimal example: https://github.com/gatisnolv/coursier-issue-2906

Reproduction:
Run mvn install in each of ./parent, ./parent/child directories to install the projects to the Maven local repository.
Observe the difference in result when running inside of the ./parent/child directory mvn dependency:tree against the output of cs resolve -q --cache "./" --repository "http://localhost:8080/" org.fake:child:1.0-SNAPSHOT; rm -rf http*

Note: in the cs resolve command I specify to use as cache the current directory, and do an rm -rf http* after it's done to get updated results in the next run if I change something in the poms (and reinstall them again with mvn install).

[ppkarwasz]

@gatisnolv, thanks, I corrected my message.

For the examples, it is better to point at the published versions, since those in Git can change:

• child POM,
• parent POM