Problem with building with maven 3.8.2

[pzygielo]

Since maven 3.8.2 (which includes apache/maven@5a89973 that I think is the cause of change) the EL can no longer be built due to directory-maven-plugin not being compatible (and BTW probably dead anyway).

It results with:

[ERROR] Failed to execute goal org.commonjava.maven.plugins:directory-maven-plugin:0.3.1:highest-basedir (find-project-root) on project org.eclipse.persistence.parent: Cannot find a single highest directory for this project set. First two candidates directories don't share a common root. -> [Help 1]

As maven versions are not specified exactly in

eclipselink/.github/workflows/codeql-analysis.yml

Line 57 in c0f808e

- run: mvn -B clean package -DskipTests

or in

eclipselink/etc/jenkins/pr_verify.groovy

Line 94 in c0f808e

maven 'apache-maven-latest'

they might be upgraded out of control of this project.

Please consider taking action before that happens.

[michael-o]

Do you consider this to be a regression or just surfaced a bug in the mentioned plugin?

[pzygielo]

Do you consider this to be a regression or just surfaced a bug in the mentioned plugin?

As MNG-7170 is classified as improvement, I'd think that this is regression in maven, unexpected in microrelease (3.8.1 to 3.8.2).

maven-3.8.2 declares

Fixes and non-invasive backports from Maven 4.0.0-alpha-1.

I have not investigated the plugin itself, so have no idea what happens there to result with:

Caused by: org.apache.maven.plugin.MojoExecutionException: Cannot find a single highest directory for this project set. First two candidates directories don't share a common root.
    at org.commonjava.maven.plugins.execroot.HighestBasedirGoal.findDirectory (HighestBasedirGoal.java:121)
    at org.commonjava.maven.plugins.execroot.AbstractDirectoryGoal.execute (AbstractDirectoryGoal.java:80)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)

But this works with 3.8.1 and it doesn't break the build.

Nothing related seems to be mentioned in known-issues yet.

[michael-o]

It could be a regression, but also just a bug in the plugin. @jdcasey, can you help out on your plugin? @mickaelistria any idea?

@pzygielo Then this plugin will be broken on Maven 4 as well. Reverting just fix the symptom, not the root cause. It would be very helpful if you could isolate this with a sample project and create an issue with Maven.

[pzygielo]

I have not investigated the plugin itself, so have no idea what happens there

With 3.8.1 files has only one element - current project.
With 3.8.2 files contains additionally parent.

I think the plugin has problem with recognizing parent now, as parent has not-null basedir.

stop at org.commonjava.maven.plugins.execroot.HighestBasedirGoal:80
monitor print p
monitor print p.getBasedir()

[michael-o]

So you are saying it retrieves the wrong value?

[mickaelistria]

I think p.getBasedir() == null is erroneously used in order to check whether p is a resolved parent. I am not aware of anything in Maven that implies such assumption; so it seems to me the building is built on a non-specified side-effect, that changed in the meantime.

[michael-o]

I think p.getBasedir() == null is erroneously used in order to check whether p is a resolved parent. I am not aware of anything in Maven that implies such assumption; so it seems to me the building is built on a non-specified side-effect, that changed in the meantime.

Thanks for the info! @pzygielo Can you locally drop this assumption and see whether the plugin works?

[rfelcman]

I tried to replace org.commonjava.maven.plugins:directory-maven-plugin:0.3.1 with following (additional debug comments there) but same issue with Maven 3.8.2:

          <plugin>
                <groupId>org.codehaus.gmaven</groupId>
                <artifactId>groovy-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <id>find-project-root</id>
                        <phase>validate</phase>
                        <goals>
                            <goal>execute</goal>
                        </goals>
                        <configuration>
                            <source>
                                <![CDATA[
                                def rootPom = project;
                                log.info("Current project parent [rootPom.parent]:  " + rootPom.parent);
                                log.info("Current project parent basedir [rootPom.parent.basedir]:  " + rootPom.parent.basedir);
                                while (rootPom.parent.basedir != null) {
                                    log.info("Current project [rootPom]:  " + rootPom);
                                    log.info("Current project basedir [rootPom.basedir]:  " + rootPom.basedir);
                                    log.info("parent project [rootPom.parent]:  " + rootPom.parent);
                                    log.info("parent project basedir [rootPom.parent.basedir]:  " + rootPom.parent.basedir);
                                    rootPom = rootPom.parent;
                                }
                                project.properties.setProperty("project.root.location", rootPom.basedir.toString());
                                log.info("EclipseLink Parent project directory [project.root.location]:  " + project.properties['project.root.location']);
                                log.info("Topmost parent directory [rootPom.basedir]:  " + rootPom.basedir);
                                ]]>
                            </source>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

[michael-o]

https://issues.apache.org/jira/browse/MNG-7215