Support Temurin JDKs with JMOD files

[Copilot]

Description:
Temurin JDK 24+ excludes JMOD files from its default archive. This adds opt-in installation of Adoptium's matching JMOD artifact through the existing java-package input.

• Adds the Temurin-specific java-package: jdk+jmods variant.
• Downloads the matching JDK and JMOD artifacts, then merges the JMODs into the installed JDK.
• Uses a distinct tool-cache entry for JDKs that include JMODs.
• Rejects jdk+jmods for unsupported distributions.
• Documents usage and adds focused coverage.

with:
  distribution: temurin
  java-version: '25'
  java-package: jdk+jmods

Related issue:
#804

Check list:

• Ran npm run check locally (format, lint, build, test) and all checks pass.
• Mark if documentation changes are required.
• Mark if tests were added or updated to cover the changes.

• Fixes Support Temurin JMOD distribution #804

[Copilot]

Pull request overview

This pull request adds an opt-in jmod input to support installing Temurin JDKs with JMOD files (needed because Temurin JDK 24+ no longer includes JMODs in the default JDK archive). It extends the Temurin installer to optionally download the matching Adoptium “jmods” artifact, merge it into the installed JDK, and cache that JDK separately.

Changes:

• Adds a new jmod boolean input (action input + constants + wiring into installer options).
• Extends Temurin installation to optionally download and merge the “jmods” image and cache it under a distinct toolcache folder suffix.
• Updates docs and adds focused Temurin installer test coverage for the new behavior.

Show a summary per file

File	Description
src/setup-java.ts	Reads jmod input and passes it through installer options.
src/distributions/temurin/installer.ts	Implements optional JMOD download/merge and toolcache folder suffixing.
src/distributions/base-models.ts	Adds optional jmod?: boolean to installer options model.
src/constants.ts	Adds INPUT_JMOD constant.
action.yml	Exposes jmod as a supported action input.
docs/advanced-usage.md	Documents jmod: true usage for Temurin.
tests/distributors/temurin-installer.test.ts	Adds tests for image_type=jmods, toolcache folder naming, and JMOD merge path.
dist/setup/index.js	Updates compiled distribution output for setup action.
dist/cleanup/index.js	Updates compiled distribution output for cleanup action constants.

Review details

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• Files reviewed: 7/9 changed files
• Comments generated: 2
• Review effort level: Low

[Copilot]

Review details

Comments suppressed due to low confidence (2)

src/distributions/temurin/installer.ts:180

• The JMODs archive extracted from Adoptium uses a JDK-like top-level directory that itself contains a jmods/ subdirectory. Copying the extracted root directory into ${javaHome}/jmods will nest paths (e.g., ${javaHome}/jmods/<extracted-root>/jmods/...) rather than placing the .jmod files directly under ${javaHome}/jmods.

Copy the jmods directory from within the extracted artifact (and account for macOS Contents/Home) instead of copying the artifact root.

    const jmodsDirectory = path.join(
      extractedJmodsPath,
      fs.readdirSync(extractedJmodsPath)[0]
    );
    fs.cpSync(jmodsDirectory, path.join(javaHome, 'jmods'), {recursive: true});

tests/distributors/temurin-installer.test.ts:520

• This test asserts the fs.cpSync source as the extracted artifact root (.../jdk-25-jmods). With the intended behavior of merging JMODs into the JDK, the copy source should be the jmods directory inside the extracted artifact (and Contents/Home/jmods on macOS). Update the expectation to match the correct copy semantics.

    );
    expect(spyCopySync).toHaveBeenCalledWith(
      path.join('/tmp/extracted-jmods', 'jdk-25-jmods'),
      process.platform === 'darwin'
        ? path.join('/tmp/extracted', 'jdk-25', 'Contents', 'Home', 'jmods')
        : path.join('/tmp/extracted', 'jdk-25', 'jmods'),
      {recursive: true}

• Files reviewed: 7/8 changed files
• Comments generated: 0 new
• Review effort level: Low

[Copilot]

Review details

• Files reviewed: 7/8 changed files
• Comments generated: 0 new
• Review effort level: Low