maven dependency range does not work as expected - maven-2

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 or if you have more than one POM. 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)
That should give you the highest version with the same API (i.e. all bug fixes but no breaking changes).
This document shows how Maven interprets versions: https://maven.apache.org/enforcer/enforcer-rules/versionRanges.html
The first line seems to support your position (4.8 means "at least 4.8") but there is a catch: Maven will only select a higher version if anyone specifically asks for it. So unless you have more POMs in your build and one of those asks for 4.8.2, 4.8 is "good enough" for Maven.
Think of it as a hint for conflict resolution. If POM A asks for 4.8 and B asks for 4.8.2 and B depends on A, then Maven has to make a decision. Should it fail? Should it use 4.8? Or 4.8.2?
The rules resolve this conflict by picking 4.8.2 without giving a warning or an error.
If A asks for [4.8], you'd get an error instead since Maven can't silently "upgrade" the dependency to 4.8.2 and it certainly can't downgrade 4.8.2 to 4.8.

Answer 2

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).

Answer 3

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 4

In my case, everything was working but out of the sudden I got this error
No versions are present in the repository for the artifact with a range [x,y)
I went to the library location inside .m2/repository folder and deleted the whole folder,
if you removed folder of a specific version of the lib it won't work, should remove folders of all versions of that lib
one more thing, if the lib is transitive you might need to remove all libraries in the dependency path
hope this helps you