That's effectively what happens already, if you use nix-shell. I'm concerned mostly about users who don't know to do that. Someone trying to run a script from a different brand of unix, for example.
In theory, if there is a java binary on the PATH, there should also be a JAVA_HOME. That's Oracle's take on this, but... well, I prefer Nix to have as few surprises as possible. On Sun, Mar 6, 2016 at 8:12 PM zimbatm <zimb...@zimbatm.com> wrote: > What if the JRE(s) also included a `java-env.sh` that can be sourced ? > Then it's easy to build wrappers that source it dynamically. > > On Sat, 5 Mar 2016 at 17:34 Svein Ove Aas <sve...@gmail.com> wrote: > >> Context: https://github.com/NixOS/nixpkgs/issues/13653 >> >> There are a few packages which can't be considered properly installed >> (and usable) without setting environment variables, this example being the >> Java development kit. >> >> Some Java-based tools need to know where to find the JDK. The way they do >> this is by looking at the JAVA_HOME environment variable. That is... >> currently, it isn't set at all, unless you use nix-shell or an equivalent >> mechanism. >> >> I've thought of a couple of solutions, but would welcome other >> suggestions. In no particular order... >> >> (The problem is not restricted to just JAVA_HOME.) >> >> - Wrapping the the JDK binaries with makeWrapper. >> This is a non-starter, as it's common to use JAVA_HOME in scripts. >> >> - JAVA_HOME is set in the JDK's setup-hook. We can source that file on >> shell startup. >> This works well for nix-shell, and is the approach I've chosen to take >> globally for a temporary fix. Unfortunately, it is in a sense even worse >> than the status quo. Since this produces a pointer into /nix/store, the >> value of JAVA_HOME in a running shell can become invalid because the JDK in >> question is GC'd (!), or superseded by a newer one *without* being deleted >> (!!). >> >> - Adding another directory under /run, containing symlinks that we can >> mutate. >> Has the obvious problem of impurity, but we're talking about system (or >> user) profiles; they're already impure, in the same sense. I don't see any >> technical issues here, but that doesn't mean there aren't any. I'm not sure >> how to implement it, or even whether I should. >> We'd have "JAVA_HOME=/run/env/JAVA_HOME", or so. >> >> One further concern... >> >> - Right now, the only way to install Java system-wide is to put it in >> environment.systemPackages. Or using nix-env. Either way, JAVA_HOME >> wouldn't get set; this is true even with that PR. I've been trying to think >> of ways to fix this, but I have no idea how. Send help! >> As a result, even if I add programs.java to NixOS, it doesn't help >> anyone who's got the problem right now. >> >> .... >> >> I'd like to implement a general solution for all such situations, ideally >> one that would get merged. Rant over, though. Thoughts? >> > _______________________________________________ >> nix-dev mailing list >> nix-dev@lists.science.uu.nl >> http://lists.science.uu.nl/mailman/listinfo/nix-dev >> >
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