Fix import-safe checks when scripts are run from a path with symlinks

[otaconix]

Description:
In v6, setup-java was made "import-safe" to facilitate testing. This prevents setup-java & cleanup-java from doing anything when their sources get imported.

This works fine in the general case, but actually invoking the script (node setup-java/index.js) when the path to the script contains symlinks led to the script incorrectly believing it was imported, and refuse to actually run.

To fix this, we pass process.argv[1] through fs.realpathSync, which resolves symlinks in the path.

Fixes #1264

NB: I did run tests, and all but one succeeded, which I think is unrelated to my changes: the Jetbrains distributor test that checks getAllAvailableVersions times out on my machine.

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.

[Copilot]

🔵 Needs a closer look

fs.realpathSync(process.argv[1]) is currently unguarded and can throw in valid import/eval contexts, breaking the intended import-safe behavior by crashing during module evaluation.

Pull request overview

This PR fixes the “import-safe” entrypoint check so setup-java / cleanup-java still execute when invoked via a path containing symlinks, by canonicalizing process.argv[1] before comparing it to import.meta.url.

Changes:

• Resolve symlinks in process.argv[1] via fs.realpathSync in the import-safe guard (setup + cleanup).
• Add fs.realpathSync mocks in Jest tests to accommodate the new call.
• Update the committed dist/ bundles to reflect the source changes.

File summaries

File	Description
src/setup-java.ts	Updates the main-module check to compare a realpath-resolved argv path.
src/cleanup-java.ts	Adds fs import and updates the main-module check similarly.
dist/setup/index.js	Updates the bundled entrypoint check accordingly.
dist/cleanup/index.js	Bundles the new fs import and updates the entrypoint check.
tests/setup-java.test.ts	Extends the fs mock to include realpathSync.
tests/setup-java.module-loading.test.ts	Extends the fs mock to include realpathSync.

Review details

Suppressed comments (2)

src/cleanup-java.ts:86

• Same as setup-java: calling fs.realpathSync(process.argv[1]) at module top-level can throw when process.argv[1] is absent or not a valid path (e.g., node -e, REPL), preventing the module from being safely imported. Wrap the resolution and fall back to the original argv value so the import-safe guard never crashes.

if (fs.realpathSync(process.argv[1]) === fileURLToPath(import.meta.url)) {
  run();
} else {
  // https://nodejs.org/api/modules.html#modules_accessing_the_main_module
  core.info('the script is loaded as a module, so skipping the execution');
}

src/setup-java.ts:180

• fs.realpathSync(process.argv[1]) can throw (e.g., when the module is imported under node -e, REPL, or other contexts where process.argv[1] is missing or not a real file path). That would break the intended “import-safe” behavior by crashing during module evaluation. Consider guarding realpathSync (try/catch or an existsSync check) and falling back to the raw process.argv[1] string when it cannot be resolved.

if (fs.realpathSync(process.argv[1]) === fileURLToPath(import.meta.url)) {
  run();
} else {
  // https://nodejs.org/api/modules.html#modules_accessing_the_main_module
  core.info('the script is loaded as a module, so skipping the execution');
}

• Files reviewed: 4/6 changed files
• Comments generated: 0
• Review effort level: Lite

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[Copilot]

🟡 Changes recommended

Missing argument guards can break imports, and the symlink regression lacks effective test coverage.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

• Files reviewed: 7/9 changed files
• Comments generated: 4
• Review effort level: Balanced