Gradle extension causes debugger extension to not include runtimeOnly dependencies in classpath when debugging

[jrussellsmyth]

Extension Name: vscode-gradle
Extension Version: 3.16.4
OS Version: devcontainer with Linux ffc491a711d0 6.6.71-0-virt #1-Alpine SMP PREEMPT_DYNAMIC 2025-01-10 14:56:02 aarch64 GNU/Linux
VSCode version: April 2025 (version 1.100)

Describe the bug
runtimeOnly gradle dependencies are not properly identified and added to debug classpath. Does not happen with vscode java debugger without gradle extension.

To Reproduce
Demo repo here

In a project with runtimeOnly dependency, with runtime discovery processes, debug using the vscode java debuger. The classpath is not set correctly and the runtime discovery will fail.

Running with gradle command line succeeds.

Demo repo includes launch config with classpath workaround.

This is particularly problematic for Spring projects with -starter style libraries that configure implementations to be loaded via jar manifests.

Expected behavior
Classpath should be set based on gradle project definition

Screenshots
If applicable, add screenshots to help explain your problem.

Output from "Gradle for Java"
nothing of interest

Does the bug still exist if you disable all other extensions?
Yes

[github-actions]

Hi @jrussellsmyth, I'm an AI Support assistant here to help with your issue. While the team reviews your request, I wanted to provide some possible tips and documentation that might help you in the meantime.

Solution

• Disable the new Gradle build server so the classpath is computed by the legacy importer (which includes runtimeOnly jars). In your VS Code settings.json:

  {
    "gradle.experimental.buildServer.enabled": false
  }

  This restores the old classpath resolution (see issue #1402).

• As a workaround, generate the runtime classpath via Gradle and reference it directly in your launch.json. For example, add a preLaunchTask:

  {
    "preLaunchTask": "printRuntimeClasspath",
    "java": {
      "classpath": ["${workspaceFolder}/.classpath-runtime"]
    }
  }

  where printRuntimeClasspath is a Gradle task that writes runtimeClasspath to .classpath-runtime:

  task printRuntimeClasspath {
    doLast {
      file(".classpath-runtime").text = configurations.runtimeClasspath.files
        .collect { it.toString() }
        .join(File.pathSeparator)
    }
  }

Other references with low confidence

Dependency with scope test in gradle falls into the main classpath

• Title: Dependency with scope test in gradle falls into the main classpath
• Description: Test-scoped dependencies end up in the main classpath due to the Gradle build server import.
• Issue URL: Dependency with scope test in gradle falls into the main classpath redhat-developer/vscode-java#3777

The team will respond to your issue shortly. I hope these suggestions are helpful in the meantime. If this comment helped you, please give it a 👍. If the suggestion was not helpful or incorrect, please give it a 👎. Your feedback helps us improve!