Allow to define a JAVA_HOME variable for each installation

[laeubi]

Description:

We have a setup where we need different JVM versions in parallel, for that we call the setup step multiple times and setup later a toolchain using the env variables. This works fine for Java 11 / 17 but with java 18 it produces a JAVA_HOME_8X64 instead of JAVA_HOME18_X64

Task version:
v3

Platform:

• Ubuntu
• macOS
• Windows

Runner type:

• Hosted
• Self-hosted

Repro steps:
You can find a run here: https://github.com/eclipse/tycho/runs/6737378073
If you open the "Build Tycho" step, there is a list of env variables and one can see the following ones:

Expected behavior:
I want to see an env variable named JAVA_HOME_18_X64

Actual behavior:
I see an env variable JAVA_HOME_8_X64 is created instead

[dmitry-shibanov]

Hello @laeubi. Thank you for your report. The action does not produce such kind of env variable. It produces only JAVA_HOME.

[laeubi]

@dmitry-shibanov so who is setting the variable then? I can only tell that adding this action makes both variables aviable JAVA_HOME and JAVA_HOME_<version>_<arch>.

[laeubi]

By the way this was mentioned here:

• Support multiple JDKs during build #44 (comment)

[dmitry-shibanov]

@laeubi I've printed env variables by pattern JAVA_HOME*. Only the JAVA_HOME env variable is changed.

[laeubi]

@dmitry-shibanov first this is what I mean:

so somehow it is added but I have no idea why (maybe as result of tool install?) :-)

Only the JAVA_HOME env variable is changed.

Maybe the action can then be changed to explicitly set those variables? This is incredible useful for such purposes where one needs many JVMs in the same run...

[dmitry-shibanov]

@laeubi The JAVA_HOME_* env variables are created during image generation here. The action does not modify them.

[laeubi]

It seems in (older) versions of the script, they where also produced (or overridden) by the setup action:

setup-java/src/installer.ts

Lines 76 to 79 in b52cd69

	let extendedJavaHome = 'JAVA_HOME_' + version + '_' + arch;
	core.exportVariable('JAVA_HOME', toolPath);
	core.exportVariable(extendedJavaHome, toolPath);
	core.addPath(path.join(toolPath, 'bin'));

do you think such a feature could be added back? Maybe even by make the env variable configurable and defaulting to JAVA_HOME?

[laeubi]

Duplicate of #44