Maven cannot find a local dependancy

Question

I am trying to follow instructions on this site:

http://trac.erichseifert.de/warp/wiki/DeveloperGuide

I have got all the source - and have done mvn install on both mpqparser and vectorgraphics2d - then I go into the gral folder - and try running it, I am met with this error:

> $ mvn install
[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for
de.erichseifert.gral:GRAL:jar:0.8
[WARNING] 'reporting.plugins.plugin.version' for org.apache.maven.plugins:maven-
changelog-plugin is missing. @ line 143, column 17
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten t
he stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support buildin
g such malformed projects.
[WARNING]
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building GRAL Graphing Library 0.8
[INFO] ------------------------------------------------------------------------
[WARNING] The POM for de.erichseifert.vectorgraphics2d:VectorGraphics2D:jar:0.6
is missing, no dependency information available
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.329s
[INFO] Finished at: Sun Apr 22 00:18:13 BST 2012
[INFO] Final Memory: 3M/122M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project GRAL: Could not resolve dependencies f
or project de.erichseifert.gral:GRAL:jar:0.8: Failure to find de.erichseifert.ve
ctorgraphics2d:VectorGraphics2D:jar:0.6 in http://repo.maven.apache.org/maven2 w
as cached in the local repository, resolution will not be reattempted until the
update interval of central has elapsed or updates are forced -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e swit
ch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please rea
d the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyReso
lutionException

I presume it is trying to load the jar which was just built in the vectorgraphics2D folder - but I am not sure if the wiki instructions are missing a step, or if something needs to be set.

The pom.xml for gral has the following as its dependancy statement:

<dependencies>
        <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.8.1</version>
                <scope>test</scope>
                <optional>true</optional>
        </dependency>
        <dependency>
                <groupId>de.erichseifert.vectorgraphics2d</groupId>
                <artifactId>VectorGraphics2D</artifactId>
                <version>0.6</version>
        <optional>true</optional>
        </dependency>
  </dependencies>

Please can somebody help me through this - this is my first experience of maven!

Answer 1

as siegl says in the comments, it sounds like you didn't install version 0.6 of VectorGraphics2D - if you had, the jar should have appeared in the directory ~/.m2/repository/de/erichseifert/vectorgraphics2d/VectorGraphics2D/0.6. the fact that you also have a directory ~/.m2/repository/de/erichseifert/vectorgraphics2d/VectorGraphics2D/0.9-SNAPSHOT sounds suspiciously like that is what you build and installed instead.

maven's repo is quite simple to understand - the directories are just made from the group and artifact IDs and the version.

and the above makes sense - the instructions you gave tell you to build the trunk of VectorGraphics2D, which is probably no longer 0.6.

so you have two options - either change the dependency to 0.9-SNAPSHOT in the gral pom and try linking to that, or check out and build the 0.6 version of VectorGraphics2D. i would suggest doing the latter because it is more likely to work as expected (the API in 0.9 may have changed).

from http://trac.erichseifert.de/vectorgraphics2d/browser#tags it looks like you want:

rm vectorgraphics2d
svn co svn://erichseifert.de/vectorgraphics2d/tags/0.6 vectorgraphics2d

and then continue as before.

Answer 2

The point is that the GRAL is comming from a tag which means it is a stable version. That means you need to change the dependencies of mpqparser and vectorgraphics2d to their appropriate version (...-SNAPSHOT) and try it another time...but before you need to delete the .m2/repository/erichseifert/... folder first...