[MNG-8598] Add support for MAVEN_PROJECTBASEDIR substitution in jvm.config

[jira-importer]

Marc Guillemot opened MNG-8598 and commented

We use lombok together with the ecj compiler in a large project. For that, we use lombok.jar as java agent for maven (corresponds to the official lombok documentation: https://projectlombok.org/setup/ecj),).

At the root level of the project, this is quite easy

.mvn/jvm.config:

-javaagent:lombok.jar=ECJ

We want to be able to call mvn in any module of the project, which means that each submodule needs to have its own .mvn/jvm.config with the relative path to the lombok.jar file, otherwise maven can't start because the agent is not found:

• at depth 1: -javaagent:../lombok.jar=ECJ
• at depth 2: -javaagent:../../lombok.jar=ECJ
• at depth 3: -javaagent:../../../lombok.jar=ECJ
• ...

This is naturally very annoying and error prone (new modules need to have their .mvn/jvm.config and relative paths have to be adapted when moving modules).

 

It seems to me that maven doesn't provide currently any better way to achieve that (I hope, I'm wrong) but that this could be achieved improving the {}mvn.bat{}/{}mvn{} scripts with:

• interpolation of contained variables ({}MAVEN_PROJECTBASEDIR{} would be the interesting one)
• support for two different jvm.config files allowing bat/sh specific references for variables.
  In our case it would be a "sh.jvm.config" with -javaagent:$MAVEN_PROJECTBASEDIR/lombok.jar=ECJ and a "bat.jvm.config" with {}-javaagent:%MAVEN_PROJECTBASEDIR%\lombok.jar=ECJ{}.

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Affects: 3.9.6

Remote Links:

• GitHub Pull Request #2194
  

[jira-importer]

Tamas Cservenak commented

Since Maven 3.9.2 this was implemented: MNG-7774
In short, it allows you to use these two expressions ${session.rootDirectory} and ${session.topDirectory} in maven.config and CLI. Given jvm.config ends up on CLI (mvn script handles that, pretty much same as MAVEN_OPTS), you should be able to use former one.

[jira-importer]

Marc Guillemot commented

Tamas Cservenak sorry, but I don't understand your point. From my understanding, due to the fact that jvm.config is handled by the mvn scripts, access to maven objects is not possible. Can you explain where I'm wrong here?

[jira-importer]

Tamas Cservenak commented

You are right, I was wrong here.

Maven 4 got a feature that a) interpolates command line and b) exposes new properties session.rootDirectory (and top), and this was "lightly" backported to Maven 3.9.2 as part of MNG-7774. So this I wrote above would work IF the expression would end up on Maven command line (it would be interpolated). Again, as Maven 3.9.2 got "light backport", the expression, while it looks like "maven object property", is in fact not, is "just an expression".

Still, as jvm.config ends up of Java (but not on Maven) command line, it will be NOT interpolated. So this is where I was wrong.

https://github.com/apache/maven/blob/maven-3.9.x/apache-maven/src/bin/mvn#L200

[jira-importer]

Marc Guillemot commented

Thanks for the explanation.

[jira-importer]

Guillaume Nodet commented

Marc Guillemot I think adding support for interpolating MAVEN_PROJECTBASEDIR inside jvm.config makes sense and can be implemented inside the main script. Do you want to raise a PR for that ?

[jira-importer]

Marc Guillemot commented

gnodet what do you propose for a linux versus a windows version of jvm.config?

[jira-importer]

Guillaume Nodet commented

Marc Guillemot not sure what's technically feasible. If possible, I'd replace $MAVEN_PROJECTBASEDIR or ${MAVEN_PROJECTBASEDIR} in both files and avoid two different jvm.config files. The same feature will have to be ported to mvnd too.

[jira-importer]

Guillaume Nodet commented

It seems to be doable. We'd need an IT, but the following may work:

@setlocal EnableExtensions EnableDelayedExpansion
set JVM_CONFIG_MAVEN_OPTS=
for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do (
    set "line=%%a"
    set "line=!line:$MAVEN_PROJECTBASEDIR=!MAVEN_PROJECTBASEDIR!!"
    set "line=!line:${MAVEN_PROJECTBASEDIR}=!MAVEN_PROJECTBASEDIR!!"
    set JVM_CONFIG_MAVEN_OPTS=!JVM_CONFIG_MAVEN_OPTS! !line!
)
@endlocal & set MAVEN_OPTS=%MAVEN_OPTS% %JVM_CONFIG_MAVEN_OPTS%

And we'd need something similar for the shell script:

1. concatenates all lines of a file and replaces variables
concat_lines() {
  if [ -f "$1" ]; then
    while IFS= read -r line || [ -n "$line" ]; do
1. Replace both ${MAVEN_PROJECTBASEDIR} and $MAVEN_PROJECTBASEDIR with actual value
      line=${line//\$\{MAVEN_PROJECTBASEDIR\}/$MAVEN_PROJECTBASEDIR}
      line=${line//\$MAVEN_PROJECTBASEDIR/$MAVEN_PROJECTBASEDIR}
      printf "%s " "$line"
    done < "$1"
  fi
}

MAVEN_OPTS="$MAVEN_OPTS `concat_lines "$MAVEN_PROJECTBASEDIR/.mvn/jvm.config"`"