versions:display-plugin-updates does not understand maven-enforcer-plugin

[caseboltj]

(This is more of a "did this tracker get lost in the transition to mojohaus" tracker than a new issue...)

I removed the deprecated prerequisites stanza from my POM in favor of using the enforcer plugin.

Now, when running versions:display-plugin-updates, existing updates are not found and a message is displayed stating that I need to add the prereqs info back into the POM.

According to http://stackoverflow.com/questions/29344809/versionsdisplay-plugin-updates-does-not-understand-maven-enforcer-plugin , there was a tracker (MVERSIONS-272) on codehaus for this issue.

I searched open and closed trackers here at mojohaus, and did not find anything.

Did the original tracker get closed, or did it just miss the transition?

[informatik01]

Here is the archived version of that issue page:
https://web.archive.org/web/20150514123930/http://jira.codehaus.org/browse/MVERSIONS-272

[brunchboy]

Yes, it seems that I am now in a damned-if-I-do, damned-if-I-don’t situation. I have added the enforcer plugin, but if I leave the prerequisites stanza in my pom.xml then I get a warning about it being deprecated when I build, and if I omit it, I get an error when I try to run versions:display-plugin-updates. Is there a correct answer?

[khmarbaise]

The current version (2.3) of versions-maven-plugin does not correctly handle that. The correct way since Maven 3 is to remove the prerequisites for non-plugin projects. But the problem is located in the versions-maven-plugin.

[ptamarit]

Hi,

If this can help, here are some example with Maven v3.5.0 and versions plugin v2.4 using the command mvn versions:display-plugin-updates:

• Using prerequisites triggers a Maven warning but is well understood by the versions plugin.
• Using enforcer works well with Maven but triggers an error with the versions plugin.

pom-prereq.txt
out-prereq.txt
pom-enforcer.txt
out-enforcer.txt

Cheers,
Pablo

[garretwilson]

Is there a correct answer?

@brunchboy , no, apparently not. @dannil gave a good summary here: #173 (comment)

[brunchboy]

Sigh, indeed, I keep hoping a fixed version of the plugin will be released, but have been disappointed so far.

[PascalSchumacher]

A fix would be very nice as this is very confusing and the output of versions:display-plugin-updates is basically useless if you use the correct way and enforce the maven version with the enforcer plugin :(

[adamvoss]

Confusingly, the plugin even tells me to use the enforcer despite not respecting the setting:

[ERROR] Project does not define required minimum version of Maven.
[ERROR] Update the pom.xml to contain maven-enforcer-plugin to
[ERROR] force the maven version which is needed to build this project.
[ERROR] See https://maven.apache.org/enforcer/enforcer-rules/requireMavenVersion.html

[PascalSchumacher]

A release containing this would be highly appreciated.

[garretwilson]

So is this fixed now?

[PascalSchumacher]

@garretwilson It works for me when I use versions-maven-plugin 2.7.

[garretwilson]

Woohoo! Yeah, I just tried it. I had to add the Maven Enforcer Plugin indicating a minimum Maven version of 3.0.5, but then it worked and I didn't have to use that incorrect <prerequisites> tag anymore. Thanks so much everyone!!

[brunchboy]

@garretwilson I am not having the same luck, I still get the complaints about missing prerequisites even after adding explicit entries for versions-maven-plugin 2.7 and maven-enforcer-plugin 3.0.0-M2 configured to requireMavenVersion 3.0.5 (my Maven version is actually 3.5.4). What am I missing?

[garretwilson]

You might try looking at the latest version of our GlobalMentor parent POM I just updated it this morning to fix this problem. We haven't yet released his artifact to Maven Central, so if you find a problem in it let me know! Hopefully it will point you to what you're missing—or indicate something I missed.

[brunchboy]

Thanks, I think the problem was that I was only specifying the versions-maven-plugin version in the my reporting plugins section, because the sample configuration XML I had found contained elements that were not valid in the build section. Adding the plugin itself, without that reporting configuration, seemed to do the trick. But I also noticed you have an entire pluginManagement section that I lacked, so I added that to specify versions for all the plugins, including some that mvn versions:display-plugin-updates was complaining had no specified version, and everything seems happy now. Woo hoo! Hopefully I can go back to knowing nothing about Maven for another year or so. 😉

[caseboltj]

Thanks everyone for staying on this! As the originator of this issue, I can report that the fix is working as advertised for me.

[cowwoc]

Another thing to watch out for is that your enforcer execution should have an id of enforce-maven as mentioned at https://maven.apache.org/enforcer/enforcer-rules/requireMavenVersion.html as opposed to enforce-versions as mentioned at https://maven.apache.org/enforcer/maven-enforcer-plugin/usage.html. It's unfortunate that the enforcer's own documentation gets it wrong.

[brunchboy]

Interesting, what cares about the id?

[cowwoc]

@brunchboy My understanding of this is a bit fuzzy but going by https://maven.apache.org/guides/mini/guide-default-execution-ids.html each plugin has a default execution id. If you want to override its default configuration (for example, by default the enforcer plugin does nothing) then you must specify the execution id you're trying to override. That way if a user invokes an unrelated task (e.g. mvn clean install ... notice that they didn't explicitly invoke enforcer) then when the enforcer plugin runs it'll use your overridden configuration.

I hope that helps.

[jakub-bochenski]

The plugin documentation wasn't updated and it still talks about "taking care of Maven version prerequisites."

[onacit]

Is this problem fixed, really?