Infer Metals Java Home When Path Symlinks to Java Binary

[godenji]

Linux users may have OpenJDK provided by their package manager, which creates a symlink from /usr/bin/java to the actual java home binary.

Since Metals expects java home and not the java binary it's impossible to set the path to /usr/bin/java.

It would be highly convenient if Metals could, when presented with a file instead of a path, walk up the directory structure to actual java home directory.

The status quo is simply hard coding the current java home path, which changes often on package manager updates, so is far from ideal.

[tanishiking]

@godenji What happens if you reset metals: Java Home settings?

I guess metals-vscode (locate-java-home) will find the JAVA_HOME.
If no, do you mind running locate-java-home CLI in your environment?

$ npm install -g locate-java-home
$ locate-java-home

(In my case: I get the following JAVA_HOMEs by locate-java-home and metals-vscode will pick the latest one from the list)

❯ locate-java-home
JAVA_HOME directories found:
1.8.0_312 /Library/Java/JavaVirtualMachines/amazon-corretto-8.jdk/Contents/Home [64-bit] [JDK]
17.0.3 /Library/Java/JavaVirtualMachines/zulu-17.jdk/Contents/Home [64-bit] [JDK]
11.0.11 /Users/tanishiking/Library/Java/JavaVirtualMachines/adopt-openj9-11.0.11/Contents/Home [64-bit] [JDK]
11.0.9 /Users/tanishiking/Library/Java/JavaVirtualMachines/adopt@1.11.0-9/Contents/Home [64-bit] [JDK]
11.0.12 /Users/tanishiking/Library/Java/JavaVirtualMachines/labsjdk-ce-11.0.12-jvmci-20.3-b20/Contents/Home [64-bit] [JDK]
1.8.0_302 /Users/tanishiking/Library/Java/JavaVirtualMachines/temurin-8.jdk/Contents/Home [64-bit] [JDK]