Update minimum required Maven version declaration

[ctrueden]

Currently we declare:

  <prerequisites>
    <maven>2.2.1</maven>
  </prerequisites>

But there has now been one report of Maven 2.2.1 not successfully building a SciJava-based project: imagej/ImageJ#38

We need to investigate whether we can replicate the build failure, and if so, what caused it. Then consider updating the pom-scijava minimum version to match our test results.

[dscho]

This is what my mvn versions:display-plugin-updates says:

[INFO] The following plugin updates are available:
[INFO] maven-gpg-plugin ......................................... 1.4 -> 1.5
[INFO] maven-release-plugin ................................... 2.4.2 -> 2.5
[INFO] maven-surefire-plugin .................................. 2.16 -> 2.17
[INFO]
[INFO] All plugins have a version specified.
[INFO]
[INFO] Project defines minimum Maven version as: 2.2.1
[INFO] Plugins require minimum Maven version of: 3.0.4
[INFO]
[ERROR] Project requires an incorrect minimum version of Maven.
[ERROR] Either change plugin versions to those compatible with 2.2.1
[ERROR] or update the pom.xml to contain
[ERROR]
[ERROR] 3.0.4
[ERROR]
[INFO]
[INFO] Require Maven 3.0 to use the following plugin updates:
[INFO] org.sonatype.plugins:nexus-staging-maven-plugin ............... 1.4.7
[INFO]
[INFO] Require Maven 3.0.4 to use the following plugin updates:
[INFO] org.sonatype.plugins:nexus-staging-maven-plugin ................. 1.6

So it seems that really only the nexus-staging-maven-plugin -- something only deployers, but neither scijava-common users nor developers use -- requires a newer Maven.

My gut feeling is that we should wait with bumping the required Maven version, and when we do, we should go with 3.0.4.

As to the individual plugins:

• maven-gpg-plugin 1.5 brings only two relevant improvements, neither of which we use, really: passphrase revealed upon backspace, and the gpg-agent is used by default
• maven-release-plugin 2.5 brings two very relevant improvements: the prepare goal had a problem where it would not commit when doing the full release cycle (which we do not use that plugin for, in release-version.sh, working around that bug) and making the work around for using Git 1.8 obsolete
• maven-surefire-plugin 2.17 comes with two improvements I'd like to have: it fixes a bug where files in /tmp/ were not deleted after use, and it evaluates @{...} in the argLine property (oh, and it also allows inproc execution with java 8, but we're not there yet).

I would like to address these plugin updates with the highest priority, then complete the Herculean effort to put everything into the <pluginManagement> section, and then wait with the update of the required Maven version, maybe with an intermediate 3.0 before going the final step to 3.0.4 when needed.

[dscho]

Forget what I said about <pluginManagement>... I see that that's already done...

[dscho]

Hmpf. No release notes for the nexus-staging-maven-plugin version 1.6 I could find. Sad.

[dscho]

From sonatype/nexus-maven-plugins@nexus-maven-plugins-1.5.1...nexus-maven-plugins-1.6 it looks as if the two major improvements are stricter SSL handling and some m2e fixes. I'm inclined to update our dependency...

[dscho]

See #5. Disclaimer: I did not test any build with this yet, but I do not expect any regression... Having said that, I am not "online enough" today to merge this.

[ctrueden]

Since you bumped to a SNAPSHOT, I merged it.

[dscho]

I guess that we can close this issue for now, right, @ctrueden?

[ctrueden]

Oops, yep! Thanks.