Linkage Checker does not report paths to missing artifacts

[suztomo]

When checking a BOM with MaximumLinkageErrorsTest, Linkage Checker does not show the path(s) to the missing artifact.

I had to run debugger for LinkageChecker class to find the artifactProblems in ClassPathResult instance:

GoogleCloudPlatform/cloud-sql-jdbc-socket-factory#507 (comment)

xerces:xerces-impl:jar:2.6.2 was not resolved. Dependency path: com.google.cloud.sql:cloud-sql-connector-r2dbc-core:jar:1.2.3 (compile) > io.projectreactor.netty:reactor-netty:jar:1.0.6 (compile) > io.projectreactor.netty:reactor-netty-core:jar:1.0.6 (compile) > io.micrometer:micrometer-core:jar:1.5.0 (compile?) > com.hazelcast:hazelcast:jar:4.0.1 (compile?) > org.codehaus.groovy:groovy-all:jar:2.1.8 (provided?) > com.thoughtworks.xstream:xstream:jar:1.4.2 (compile?) > cglib:cglib-nodep:jar:2.2 (compile?) > ant:ant:jar:1.6.2 (compile?) > xerces:xerces-impl:jar:2.6.2 (compile?)
xml-apis:xml-apis:jar:2.6.2 was not resolved. Dependency path: com.google.cloud.sql:cloud-sql-connector-r2dbc-core:jar:1.2.3 (compile) > io.projectreactor.netty:reactor-netty:jar:1.0.6 (compile) > io.projectreactor.netty:reactor-netty-core:jar:1.0.6 (compile) > io.micrometer:micrometer-core:jar:1.5.0 (compile?) > com.hazelcast:hazelcast:jar:4.0.1 (compile?) > org.codehaus.groovy:groovy-all:jar:2.1.8 (provided?) > com.thoughtworks.xstream:xstream:jar:1.4.2 (compile?) > cglib:cglib-nodep:jar:2.2 (compile?) > ant:ant:jar:1.6.2 (compile?) > xml-apis:xml-apis:jar:2.6.2 (compile?)
maven-plugins:maven-cobertura-plugin:plugin:1.3 was not resolved. Dependency path: com.google.cloud.sql:cloud-sql-connector-r2dbc-core:jar:1.2.3 (compile) > io.projectreactor.netty:reactor-netty:jar:1.0.6 (compile) > io.projectreactor.netty:reactor-netty-core:jar:1.0.6 (compile) > io.micrometer:micrometer-core:jar:1.5.0 (compile?) > ch.qos.logback:logback-classic:jar:1.2.3 (compile?) > org.codehaus.groovy:groovy-all:jar:2.4.0 (compile?) > com.thoughtworks.xstream:xstream:jar:1.4.7 (compile?) > org.jdom:jdom:jar:1.1.3 (compile?) > jaxen:jaxen:jar:1.1.3 (compile?) > dom4j:dom4j:jar:1.6.1 (compile) > jaxen:jaxen:jar:1.1-beta-6 (compile?) > jdom:jdom:jar:1.0 (compile) > jaxen:jaxen:jar:1.0-FCS (compile?) > maven-plugins:maven-cobertura-plugin:plugin:1.3 (compile)
maven-plugins:maven-findbugs-plugin:plugin:1.3.1 was not resolved. Dependency path: com.google.cloud.sql:cloud-sql-connector-r2dbc-core:jar:1.2.3 (compile) > io.projectreactor.netty:reactor-netty:jar:1.0.6 (compile) > io.projectreactor.netty:reactor-netty-core:jar:1.0.6 (compile) > io.micrometer:micrometer-core:jar:1.5.0 (compile?) > ch.qos.logback:logback-classic:jar:1.2.3 (compile?) > org.codehaus.groovy:groovy-all:jar:2.4.0 (compile?) > com.thoughtworks.xstream:xstream:jar:1.4.7 (compile?) > org.jdom:jdom:jar:1.1.3 (compile?) > jaxen:jaxen:jar:1.1.3 (compile?) > dom4j:dom4j:jar:1.6.1 (compile) > jaxen:jaxen:jar:1.1-beta-6 (compile?) > jdom:jdom:jar:1.0 (compile) > jaxen:jaxen:jar:1.0-FCS (compile?) > maven-plugins:maven-findbugs-plugin:plugin:1.3.1 (compile)
com.jcraft:jsch.agentproxy:jar:0.0.6 was not resolved. Dependency path: com.google.cloud.sql:cloud-sql-connector-r2dbc-core:jar:1.2.3 (compile) > io.projectreactor.netty:reactor-netty:jar:1.0.6 (compile) > io.projectreactor.netty:reactor-netty-core:jar:1.0.6 (compile) > io.micrometer:micrometer-core:jar:1.5.0 (compile?) > ch.qos.logback:logback-classic:jar:1.2.3 (compile?) > org.codehaus.groovy:groovy-all:jar:2.4.0 (compile?) > org.apache.ivy:ivy:jar:2.4.0 (compile?) > com.jcraft:jsch.agentproxy:jar:0.0.6 (compile?)
org.jruby.joni:joni:jar:2.1.1-SNAPSHOT was not resolved. Dependency path: com.google.cloud.sql:cloud-sql-connector-r2dbc-core:jar:1.2.3 (compile) > io.projectreactor.netty:reactor-netty:jar:1.0.6 (compile) > io.projectreactor.netty:reactor-netty-core:jar:1.0.6 (compile) > io.micrometer:micrometer-core:jar:1.5.0 (compile?) > com.hazelcast:hazelcast:jar:4.0.1 (compile?) > org.jruby:jruby-complete:jar:1.7.22 (provided?) > org.jruby:jruby-core:jar:noasm:1.7.22 (provided) > org.jruby:yecht:jar:1.0 (compile) > org.jruby:jruby-core:jar:1.7.9 (provided) > org.jruby.joni:joni:jar:2.1.1-SNAPSHOT (compile)

Because the lack of visibility into the artifactProblems, I decided to investigate the dependency tree myself and created GoogleCloudPlatform/cloud-sql-jdbc-socket-factory#512. With proper messages, I wish library developers should investigate this kind of issue in near future.