[MNG-5739] Adding a test dependency can move dependencies from the compile scope to the test scope

**[Andy Wilkinson](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=awilkinson)** opened **[MNG-5739](https://issues.apache.org/jira/browse/MNG-5739?redirect=false)** and commented

I'm seeing some strange behaviour where the transitive dependencies of a test-scope dependency are causing transitive dependencies of a compile-scope dependency to become test-scoped.

A pom with a single dependency on `org.eclipse.jetty:jetty-webapp` produces the following dependencies:

```
$ mvn dependency:tree | grep org.eclipse.jetty:
[INFO] \- org.eclipse.jetty:jetty-webapp:jar:8.1.10.v20130312:compile
[INFO] +- org.eclipse.jetty:jetty-xml:jar:8.1.10.v20130312:compile
[INFO] | \- org.eclipse.jetty:jetty-util:jar:8.1.10.v20130312:compile
[INFO] \- org.eclipse.jetty:jetty-servlet:jar:8.1.10.v20130312:compile
[INFO] \- org.eclipse.jetty:jetty-security:jar:8.1.10.v20130312:compile
[INFO] \- org.eclipse.jetty:jetty-server:jar:8.1.10.v20130312:compile
[INFO] +- org.eclipse.jetty:jetty-continuation:jar:8.1.10.v20130312:compile
[INFO] \- org.eclipse.jetty:jetty-http:jar:8.1.10.v20130312:compile
[INFO] \- org.eclipse.jetty:jetty-io:jar:8.1.10.v20130312:compile
```

If I now add a test dependency on `org.apache.solr:sole-core`, a number of dependencies that were previously in the compile scope are now in the test scope:

```
$ mvn dependency:tree | grep org.eclipse.jetty:
[INFO] +- org.eclipse.jetty:jetty-webapp:jar:8.1.10.v20130312:compile
[INFO] | +- org.eclipse.jetty:jetty-xml:jar:8.1.10.v20130312:compile
[INFO] | \- org.eclipse.jetty:jetty-servlet:jar:8.1.10.v20130312:compile
[INFO] +- org.eclipse.jetty:jetty-continuation:jar:8.1.10.v20130312:test
[INFO] +- org.eclipse.jetty:jetty-deploy:jar:8.1.10.v20130312:test
[INFO] +- org.eclipse.jetty:jetty-http:jar:8.1.10.v20130312:test
[INFO] +- org.eclipse.jetty:jetty-io:jar:8.1.10.v20130312:test
[INFO] +- org.eclipse.jetty:jetty-jmx:jar:8.1.10.v20130312:test
[INFO] +- org.eclipse.jetty:jetty-security:jar:8.1.10.v20130312:compile
[INFO] +- org.eclipse.jetty:jetty-server:jar:8.1.10.v20130312:test
[INFO] +- org.eclipse.jetty:jetty-util:jar:8.1.10.v20130312:compile
```

My understanding is that this is because the shortest route to the root of the hierarchy wins and, for a number of the Jetty dependencies, the shortest route is via the test-scoped `org.apache.solr:sole-core`. I can understand a test-scoped dependency being upgraded to the compile scope when a dependency is added, but downgrading a dependency from the compile scope to the test scope feels broken to me.

I can work around the problem by using dependency management to force the dependencies into the compile scope, or by declaring direct dependencies on the transitive dependencies of `org.eclipse.jetty:jetty-webapp`, but both approaches require me to know what all those dependencies are and "duplicate" them in my pom, undermining the value of the dependencies being pulled in transitively in the first place.

---

**Attachments:**
- [pom.xml](https://issues.apache.org/jira/secure/attachment/12713285/pom.xml) (_1001 bytes_)
- [test-scope-problem.zip](https://issues.apache.org/jira/secure/attachment/12713338/test-scope-problem.zip) (_2.06 kB_)

**Issue Links:**
- [MNG-1378](https://issues.apache.org/jira/browse/MNG-1378) Make dependencies of test-jars transitive

- [MNG-7852](https://issues.apache.org/jira/browse/MNG-7852) Use all the versions for dependency resolution rather than "nearest first" or "declared first"

- [MNG-6135](https://issues.apache.org/jira/browse/MNG-6135) Maven plugins and core extensions are not dependencies, they should be resolved the same way as projects.

7 votes, 17 watchers

Start by reproducing the dependency tree with the attached pom.xml and test-scope-problem.zip, comparing the output before and after adding org.apache.solr:solr-core. Trace Maven's dependency resolution and scope selection; done means dependencies previously resolved at compile scope remain compile-scoped rather than being downgraded to test scope.

Written by the indexing model from the issue text.