Race conditions when building https://github.com/apache/jackrabbit-filevault

[kwin]

Whenever I try to execute mvnd clean verify on the master branch of https://github.com/apache/jackrabbit-filevault I get different race condition failures, e.g.

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:3.1.0:resources (default-resources) on project org.apache.jackrabbit.vault: Cannot create resource output directory: /Users/konradwindszus/git/jackrabbit-filevault/vault-core/target/classes -> [Help 1

or

[ERROR] Failed to execute goal biz.aQute.bnd:bnd-resolver-maven-plugin:5.3.0:resolve (default) on project vault-sync: Unable to resolve <<INITIAL>>: missing requirement osgi.identity;filter:='(osgi.identity=vault-sync)' [caused by: Unable to resolve vault-sync version=3.4.11.SNAPSHOT: missing requirement osgi.wiring.package;filter:='(&(osgi.wiring.package=javax.jcr)(version>=2.0.0)(!(version>=3.0.0)))';osgi.wiring.package='javax.jcr'] -> [Help 1]
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-clean-plugin:3.1.0:clean (default-clean) on project org.apache.jackrabbit.vault: Failed to clean project: Failed to delete /Users/konradwindszus/git/jackrabbit-filevault/vault-core/target/classes/org -> [Help 1]

I am a bit puzzled why the parallel execution of the modules lead to such issues. Any hints what I need to modify in the pom.xml to make it work with mvnd or did I hit a bug in mvnd?

mvnd --version
mvnd native client 0.4.3-darwin-amd64 (e20989ddd440928f392f839c282c6ef196107404)
Terminal: org.jline.terminal.impl.PosixSysTerminal with pty org.jline.terminal.impl.jansi.osx.OsXNativePty
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /usr/local/Cellar/mvnd/0.4.3/libexec/mvn
Java version: 11.0.10, vendor: AdoptOpenJDK, runtime: /Library/Java/JavaVirtualMachines/adoptopenjdk-11.jdk/Contents/Home
Default locale: en_DE, platform encoding: UTF-8
OS name: "mac os x", version: "10.16", arch: "x86_64", family: "mac"

[gnodet]

I think the problem comes from the javadoc aggregation which creates forked lifecycles and those are not properly synchronized with the main lifecycle.
Fwiw, the problem is not specific to mvnd per se, as running mvn -T4C clean verify also fails in a similar way.

[kwin]

Thanks for the input. Any other recommendation how to create an aggregate javadoc which is compliant with multi threading/mvnd?

[gnodet]

Thanks for the input. Any other recommendation how to create an aggregate javadoc which is compliant with multi threading/mvnd?

Adding the dependencies directly on the plugin definition seems to work around the problem:

    <build>
        <plugins>
            <!-- ====================================================================== -->
            <!-- J A V A D O C   P L U G I N                                            -->
            <!-- ====================================================================== -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-javadoc-plugin</artifactId>
                <configuration>
                    <!-- Default configuration for all reports -->
                    <windowtitle>Apache Jackrabbit FileVault ${project.version} API</windowtitle>
                    <doctitle>Apache Jackrabbit FileVault ${project.version} API</doctitle>
                    <excludePackageNames>
                        org.apache.jackrabbit.vault.cli*,org.apache.jackrabbit.vault.davex,*.impl*,org.apache.jackrabbit.vault.util.xml,org.apache.jackrabbit.vault.vlt.actions,org.apache.jackrabbit.vault.vlt.meta.*,org.apache.jackrabbit.vault.packaging.hotfix,org.apache.jackrabbit.vault.validation.impl*,org.apache.jackrabbit.vault.validation.spi.impl
                    </excludePackageNames>
                    <reportOutputDirectory>${basedir}/vault-doc/target/site</reportOutputDirectory>
                    <additionalparam>-notimestamp</additionalparam>
                    <detectLinks>true</detectLinks>
                    <detectJavaApiLink>true</detectJavaApiLink>
                    <links>
                        <link>https://docs.adobe.com/content/docs/en/spec/javax.jcr/javadocs/jcr-2.0/</link>
                        <link>https://jackrabbit.apache.org/api/2.20/</link>
                        <link>https://www.javadoc.io/doc/org.apache.jackrabbit/oak-jackrabbit-api/1.32.0/</link>
                    </links>
                </configuration>
                <executions>
                    <execution>
                        <id>aggregate</id>
                        <goals>
                            <goal>aggregate</goal>
                        </goals>
                        <phase>site</phase>
                    </execution>
                    <execution>
                        <id>aggregate-jar</id>
                        <goals>
                            <goal>aggregate-jar</goal>
                        </goals>
                        <phase>package</phase>
                    </execution>
                </executions>
                <dependencies>
                    <dependency>
                        <groupId>org.apache.jackrabbit.vault</groupId>
                        <artifactId>vault-cli</artifactId>
                        <version>3.4.11-SNAPSHOT</version>
                    </dependency>
                    <dependency>
                        <groupId>org.apache.jackrabbit.vault</groupId>
                        <artifactId>org.apache.jackrabbit.vault</artifactId>
                        <version>3.4.11-SNAPSHOT</version>
                    </dependency>
                    <dependency>
                        <groupId>org.apache.jackrabbit.vault</groupId>
                        <artifactId>vault-davex</artifactId>
                        <version>3.4.11-SNAPSHOT</version>
                    </dependency>
                    <dependency>
                        <groupId>org.apache.jackrabbit.vault</groupId>
                        <artifactId>vault-diff</artifactId>
                        <version>3.4.11-SNAPSHOT</version>
                    </dependency>
                    <dependency>
                        <groupId>org.apache.jackrabbit.vault</groupId>
                        <artifactId>org.apache.jackrabbit.vault.rcp</artifactId>
                        <version>3.4.11-SNAPSHOT</version>
                    </dependency>
                    <dependency>
                        <groupId>org.apache.jackrabbit.vault</groupId>
                        <artifactId>vault-sync</artifactId>
                        <version>3.4.11-SNAPSHOT</version>
                    </dependency>
                    <dependency>
                        <groupId>org.apache.jackrabbit.vault</groupId>
                        <artifactId>vault-validation</artifactId>
                        <version>3.4.11-SNAPSHOT</version>
                    </dependency>
                    <dependency>
                        <groupId>org.apache.jackrabbit.vault</groupId>
                        <artifactId>vault-vlt</artifactId>
                        <version>3.4.11-SNAPSHOT</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>

[gnodet]

Ah, and you also need to add a maven dependency from vault-sync to org.apache.jackrabbit.vault.target-osgi-environment in order to accommodate the non standard dependency expressed by https://github.com/apache/jackrabbit-filevault/blob/master/vault-sync/aem6.3.bndrun#L15

With those two changes, mvnd can build jackrabbit-filevault successfully.

The first can be considered a bug in mvn/mvnd, but the second is specifically an implicit dependency which should be made explicit.

[kwin]

Thanks a lot, I already did the latter in apache/jackrabbit-filevault@01f6c39 and in the meantime only build the javadocs during releases.

[kwin]

@gnodet Are you gonna report a bug for m-javadoc-plugin? Something I can watch?

[gnodet]

@gnodet Are you gonna report a bug for m-javadoc-plugin? Something I can watch?

The problem is not specific to the javadoc plugin, it's rather a bug in the core maven. I've sent an email to the dev list and if I open a JIRA issue, I'll link it here. We can keep this issue opened for a bit, I'll close later with the jira issue link.

[gnodet]

I've raised https://issues.apache.org/jira/browse/MNG-7156 to fix the underlying problem in maven.