Hi Ethan,
there is a far simpler solution, call org.apache.ivy.run(args, true) instead of
org.apache.ivy.main(args) in your tool provider.
regards,
Rémi
----- Original Message -----
> From: "Ethan McCue" <et...@mccue.dev>
> To: "core-libs-dev" <core-libs-dev@openjdk.java.net>
> Sent: Saturday, February 26, 2022 11:14:19 PM
> Subject: Should System.exit be controlled by a Scope Local?
> I have a feeling this has been considered and I might just be articulating
> the obvious - but:
>
> As called out in JEP 411, one of the remaining legitimate uses of the
> Security Manager is to intercept calls to System.exit. This seems like a
> decent use case for the Scope Local mechanism.
>
>
> public class Runtime {
> ...
> private final ScopeLocal<IntConsumer> EXIT =
> ScopeLocal.newInstance();
>
> ...
>
> public void overridingExitBehavior(IntConsumer exit, Runnable run) {
> ScopeLocal.with(EXIT, exit).run(run);
> }
>
> ...
>
> public void exit(int status) {
> if (EXIT.isBound()) {
> EXIT.get().accept(status);
> }
> else {
> Shutdown.exit(status);
> }
> }
> }
>
>
> One of the likely minor benefits in the scope of things, but related to the
> parts of the ecosystem I am doodling with so I'll mention it, is that it
> would become possible to wrap "naive" cli programs with the ToolProvider
> SPI without rewriting their code if this System.out, and System.err all
> became reliably configurable.
>
> For instance, Apache Ivy's CLI has a main class that looks like this
>
> https://github.com/apache/ant-ivy/blob/424fa89419147f50a41b4bdc665d8ea92b5da516/src/java/org/apache/ivy/Main.java
>
> package org.apache.ivy;
>
> public final class Main {
> ...
>
> public static void main(String[] args) throws Exception {
> try {
> run(args, true);
> System.exit(0);
> } catch (ParseException ex) {
> System.err.println(ex.getMessage());
> System.exit(1);
> }
> }
> }
>
> Making these otherwise static parts of the system configurable would enable
> a third party library to write
>
> public final class IvyToolProvider implements ToolProvider {
> @Override
> public String name() {
> return "ivy";
> }
>
> @Override
> public int run(PrintWriter out, PrintWriter err, String... args) {
> var exit = new AtomicInteger(0);
> Runtime.getRuntime().overridingExitBehavior(exit::set, () -> {
> System.overridingOut(out, () -> {
> System.overridingErr(err, Main::main);
> }
> };
> return exit.get();
> }
> }
>
> Whether that would be enough to make it so that people other than Christian
> Stein use the mechanism is anyone's guess, but might be worth a shot.
>
> https://grep.app/search?q=java.util.spi.ToolProvider
