Proper way to respect JAVA_HOME if set

[mcred]

For formulae, what is the proper way to respect the existing JAVA_HOME environment variable if it is set? When looking at different formulae, they do many different things for JAVA_HOME. JAVA_HOME: Formula["openjdk"].opt_prefix is pretty straight forward and doesn't allow for a user to set their own JAVA_HOME value. Does JAVA_HOME: "${JAVA_HOME:-#{Formula["openjdk"].opt_prefix}}" do that?

[SMillerDev]

That's the idea, but we also have overridable_java_home_env for that

[mcred]

Are Language::Java.overridable_java_home_env and JAVA_HOME: "${JAVA_HOME:-#{Formula["openjdk"].opt_prefix}}" equivalent? Which is the preferred way to a default JAVA_HOME but take the system env as the priority?

[SMillerDev]

They are equivalent. As for the preferred way, I think the homebrew function is more readable. But that's just personal preference.

[mcred]

Thank you!