maven dependency range does not work as expected

Question

Maven 2.2.1 claims to support version ranges (see e.g. http://www.sonatype.com/books/mvnref-book/reference/pom-relationships-sect-project-dependencies.html#pom-relationships-sect-version-ranges)

I tried from a brandnew maven installation the following pom:

<project>

  <modelVersion>4.0.0</modelVersion>
  <artifactId>rangetest</artifactId>
  <groupId>my.group</groupId>
  <version>1.0</version>
  <packaging>jar</packaging>

  <description>test project containing one dependency, only</description>
  <dependencies>
   <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.8</version>
    <scope>test</scope>
   </dependency>
  </dependencies>
 </project>

The dependency should resolve to junit 4.8.2, right? But instead, the version 4.8 is resolved:

C:\Users>mvn dependency:tree
[INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'dependency'.
[INFO] ------------------------------------------------------------------------
[INFO] Building Unnamed - my.group:rangetest:jar:1.0
[INFO]    task-segment: [dependency:tree]
[INFO] ------------------------------------------------------------------------
[INFO] [dependency:tree {execution: default-cli}]
[INFO] my.group:rangetest:jar:1.0
[INFO] \- junit:junit:jar:4.8:test
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2 seconds
[INFO] Finished at: Thu Oct 07 14:30:40 CEST 2010
[INFO] Final Memory: 9M/23M
[INFO] ------------------------------------------------------------------------

You might think it's an issue with Junit, as 4.8 is an existing version, but it's not. In my projects, I have versions deployed from 1.0.0 to 1.0.15 (no version 1.0!), but mvn dependency:tree complains about missing artifact of version 1.0.

Answer 1

That only works if you actually specify a version range. You use 4.8 which is a single version number, so Maven tries to resolve it directly. A version range must start with [ or ( (inclusive and exclusive, respectively).

In your case, try: [4.8,4.9)

Answer 2

There doesn't seem to be a range qualifier in your version tag. Maybe you meant to use the following to require version 4.8 or later:

<version>[4.8,]</version>

Answer 3

If you want to use version ranges, specify a version range as others pointed out. Currently, you're not.

But my real advice would be to not use version ranges at all, version ranges are a bad idea for build reproducibility and the last thing you want is a build that suddenly starts to fail because of an unknown reason. Just don't, they are a bad practice (which is probably why version ranges aren't documented anymore).