When using the Tooling API, how does one attach a debugger to the embedded gradle process that’s started? I’d like to debug a

ModelBuilder

, and using sysout debugging isn’t really working well for me.

Which embedded process? You mean the external Gradle daemon process that is started and which you can give debug properties just the usual way and then attach as debugger? :-)

That’s the one. I’ve tried passing

-Dorg.gradle.debug=true

to

modelBuilder.withArguments

, but the daemon process definitely doesn’t stop and wait for a debugger.

For a normal tooling api triggered build it works fine. Doing

GradleConnector
    .newConnector()
    .forProjectDirectory(file("."))
    .connect()
    .use {
        it
            .newBuild()
            .withArguments("-Dorg.gradle.debug=true")
            .run()
    }

stops and waits for a debugger to get attached unless other options are used like

org.gradle.debug.server = false

in the user-level

gradle.properties

.

I’m currently using Gradle 7.6. Maybe I should try a newer release

As with

org.gradle.debug.server = false

it would fail if no debugger listens, I guess you have

org.gradle.debug.suspend = false

somewhere as that would then behave as you describe. It would listen for a debugger but not wait

ProjectConnection connection = connector.connect();
        OutgoingArtifactsModel model = connection.model(OutgoingArtifactsModel.class)
                .withArguments("-Dorg.gradle.debug=true", "--init-script", copyInitScript().getAbsolutePath())
                .get();

isn’t working for me with 7.6.4.

As I said, only thing I can imagine right now is that you set

org.gradle.debug.suspend = false

somewhere. Maybe try to explicitly supply it in that call as

-Dorg.gradle.debug.suspend=true

?

Still not working, but I’m learning more about flags 🙂

Well, really strange, but hard to say from here without an MCVE

The code is all here. It builds and runs using

bazel

, so you’ll to have that available. I’d recommend installing bazelisk and renaming the binary

bazel

(you can think of

bazelisk

as the equivalent of

gradlew

, in that it allows a build to pin the version of bazel it’s using) I set the arguments to pass to the model here. Once you’ve got that, you can run everything using

bazel run private/tools/java/com/github/bazelbuild/rules_jvm_external/resolver/cmd:Resolver -- --resolver gradle 'com.google.guava:guava:33.2.1-jre'

Oh, well, I'm not going to install Bazel just to test this, sorry. That project does not qualify for the "M" in "MCVE". 🙂

Hahaha! Understandable 🙂