trying to figure out what is generating these messages

[David Bernard]

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Subject: trying to figure out what is generating these messages

Hi David --

i'm seeing these two messages in my mvn compile of my scala project:

[INFO] Checking for multiple versions of scala
[WARNING] Multiple versions of scala libraries detected!

the dependency tree is at the bottom. 2.7.3 is being omitted in favor
of 2.7.6, but the error message still comes out.

do you know how I can figure out why 2.7.3 is still being pulled in?
how i can get the scala plugin for maven to stop producting the
warning?

thanks, bob

mvn dependency:tree -Dverbose
[INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'dependency'.
[INFO] ------------------------------------------------------------------------
[INFO] Building hyperview
[INFO]    task-segment: [dependency:tree]
[INFO] ------------------------------------------------------------------------
Downloading: http://scala-tools.org/repo-releases/org/scala-lang/scala-library/2.7.3/scala-library-2.7.3.pom
666b downloaded
[INFO] [dependency:tree]
[INFO] com.HyperView:hyperview:war:1.0-SNAPSHOT
[INFO] +- org.scala-lang:scala-library:jar:2.7.6:compile
[INFO] +- net.liftweb:lift-util:jar:1.0:compile
[INFO] |  +- (org.scala-lang:scala-library:jar:2.7.3:compile - omitted
for conflict with 2.7.6)
[INFO] |  +- log4j:log4j:jar:1.2.14:compile
[INFO] |  +- javax.mail:mail:jar:1.4:compile
[INFO] |  |  \- (javax.activation:activation:jar:1.1:compile - omitted
for duplicate)
[INFO] |  +- javax.activation:activation:jar:1.1:compile
[INFO] |  +- commons-httpclient:commons-httpclient:jar:3.1:compile
[INFO] |  |  +- commons-logging:commons-logging:jar:1.0.4:compile
[INFO] |  |  \- (commons-codec:commons-codec:jar:1.2:compile - omitted
for conflict with 1.3)
[INFO] |  +- commons-fileupload:commons-fileupload:jar:1.2.1:compile
[INFO] |  +- commons-collections:commons-collections:jar:3.2.1:compile
[INFO] |  \- commons-codec:commons-codec:jar:1.3:compile
[INFO] +- net.liftweb:lift-webkit:jar:1.0:compile
[INFO] |  +- (net.liftweb:lift-util:jar:1.0:compile - omitted for duplicate)
[INFO] |  +- (org.scala-lang:scala-library:jar:2.7.3:compile - omitted
for conflict with 2.7.6)
[INFO] |  +- (log4j:log4j:jar:1.2.14:compile - omitted for duplicate)
[INFO] |  +- (javax.mail:mail:jar:1.4:compile - omitted for duplicate)
[INFO] |  +- (javax.activation:activation:jar:1.1:compile - omitted
for duplicate)
[INFO] |  +- (commons-httpclient:commons-httpclient:jar:3.1:compile -
omitted for duplicate)
[INFO] |  +- (commons-fileupload:commons-fileupload:jar:1.2.1:compile
- omitted for duplicate)
[INFO] |  +- (commons-collections:commons-collections:jar:3.2.1:compile
- omitted for duplicate)
[INFO] |  \- (commons-codec:commons-codec:jar:1.3:compile - omitted
for duplicate)
[INFO] +- net.liftweb:lift-mapper:jar:1.0:compile
[INFO] |  +- (org.scala-lang:scala-library:jar:2.7.3:compile - omitted
for conflict with 2.7.6)
[INFO] |  \- (net.liftweb:lift-webkit:jar:1.0:compile - omitted for duplicate)
[INFO] +- javax.servlet:servlet-api:jar:2.5:provided
[INFO] +- junit:junit:jar:4.5:test
[INFO] +- org.mortbay.jetty:jetty:jar:6.1.21:test
[INFO] |  +- org.mortbay.jetty:jetty-util:jar:6.1.21:test
[INFO] |  \- org.mortbay.jetty:servlet-api:jar:2.5-20081211:test
[INFO] +- org.scala-lang:scala-compiler:jar:2.7.6:test
[INFO] |  \- (org.scala-lang:scala-library:jar:2.7.6:test - omitted
for duplicate)
[INFO] \- net.databinder:dispatch-http_2.7.6:jar:0.6.0:compile
[INFO]    +- org.apache.httpcomponents:httpclient:jar:4.0:compile
[INFO]    |  +- org.apache.httpcomponents:httpcore:jar:4.0.1:compile
[INFO]    |  +- (commons-logging:commons-logging:jar:1.1.1:compile -
omitted for conflict with 1.0.4)
[INFO]    |  \- (commons-codec:commons-codec:jar:1.3:compile - omitted
for duplicate)
[INFO]    \- (org.scala-lang:scala-library:jar:2.7.6:compile - omitted
for duplicate)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL

--------------------

[David Bernard]

Hi Bob,

> [INFO] Checking for multiple versions of scala
> [WARNING] Multiple versions of scala libraries detected!
>
> the dependency tree is at the bottom. 2.7.3 is being omitted in favor
> of 2.7.6, but the error message still comes out.
>
> do you know how I can figure out why 2.7.3 is still being pulled in?
> how i can get the scala plugin for maven to stop producting the
> warning?

The scala code is not fully binary compatible (not like java).
The warning is raised because using library build with a version x of
scala could not work with a version y. The warning is produice
redardless to how maven "resolve" version.
Lift 1.0 was build to work with scala 2.7.3 => 2.7.3 is pulled.

[David Bernard]

I forgot :

You can disable the test (at your own risk) : by configuring
checkMultipleScalaVersions to false
see http://scala-tools.org/mvnsites/maven-scala-plugin/compile-mojo.html#checkMultipleScalaVersions

/davidB

[bob]

Thanks David, that helped but didn't fully answer my question.

how do i find out from the scala maven plugin itself which pom is
demanding 2.7.3?

the [WARNING] needs to identify which scala library versions were
found, and what the offending POM

[David Bernard]

You're right the plugin should alert and list dependency that require
an other version of scala without required the user to use the
dependency:tree goal (not kwon by lot of maven user).

http://github.com/davidB/maven-scala-plugin/issues/#issue/17

/davidB

[Josh Suereth]

You should make a feature request on the github project ;)

Also,  You should *not* use Scala 2.7.6 with lift as there's a bug in 2.7.6.  If things are working for you now, GREAT, but I think the first thing you'll be told upon finding issues is "use the same scala version".

- Josh