Reduce runtime dependencies from 17 packages to 10

.claude/agents/pr-fix.md

@@ -58,7 +58,7 @@ Do not edit anything when returning this block.
 
 - Edit sources: `lib/*.js` (and keep `lib/index.d.ts` in sync when you change an option, a signature, or an export); tests in `test/`; config files at the repo root (`package.json`, `.eslintrc.js`, `.mega-linter.yml`, etc.); workflows in `.github/workflows/`.
 - Keep the existing code style (ESLint `eslint:recommended` + Prettier). Use the existing `debug("java-caller")` logging pattern.
-- Run local validation that needs no network where possible: `npm run lint:fix`, then `npm run test` (set `DEBUG=java-caller` to mirror CI; the mocha timeout is 5 min because real JRE installs run). Coverage runs under `npm run test:coverage`.
+- Run local validation that needs no network where possible: `npm run lint:fix`, then `npm run test` (set `NODE_DEBUG=java-caller` to mirror CI; the mocha timeout is 5 min because real JRE installs run). Coverage runs under `npm run test:coverage`.
 - Do NOT introduce defensive hacks (skip-on-fail, retries, `|| true`, weakened assertions, broad eslint ignores) to force green - fix the root cause.
 - **npm only**, never `yarn` (it would desync `package-lock.json`).
 

.cspell.json

@@ -20,6 +20,7 @@
     "Gowans",
     "Inclusivity",
     "KICS",
+    "PATHEXT",
     "PROSELINT",
     "Perso",
     "SIGINT",
@@ -34,6 +35,7 @@
     "customarg",
     "cvfm",
     "danunafig",
+    "debuglog",
     "desync",
     "distrib",
     "djukxe",

.github/workflows/test.yml

@@ -11,6 +11,24 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+      - name: Install node
+        uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
+        with:
+          node-version: "24"
+      - name: Install dependencies
+        run: npm ci
+      - name: Run lint
+        run: npm run lint
+
   test:
     if: github.event_name != 'push' || github.ref_name == github.event.repository.default_branch
     strategy:
@@ -50,7 +68,7 @@ jobs:
         run: npm ci
       - name: Run tests
         env:
-          DEBUG: java-caller,njre
+          NODE_DEBUG: java-caller
         run: npm run test
 
   test-no-java:
@@ -73,5 +91,5 @@ jobs:
         run: npm ci
       - name: Run tests
         env:
-          DEBUG: "java-caller"
+          NODE_DEBUG: "java-caller"
         run: npm run test

.mega-linter.yml

@@ -1,6 +1,8 @@
 # Flavor & version used by mega-linter-runner and the MegaLinter agent skills
 MEGALINTER_FLAVOR: javascript
 MEGALINTER_VERSION: v10
+# The javascript flavor is a deliberate choice: skip the custom-flavor suggestions
+FLAVOR_SUGGESTIONS: false
 DISABLE_LINTERS:
   - TYPESCRIPT_STANDARD
   - TYPESCRIPT_PRETTIER

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 ## Unreleased
 
+## [6.0.0] 2026-08-09
+
+- **Breaking**: Debug traces are now activated with `NODE_DEBUG=java-caller` instead of `DEBUG=java-caller`. The `debug` package has been replaced by Node's built-in `util.debuglog`, which only reads `NODE_DEBUG` from the environment the process is launched with (setting `process.env.NODE_DEBUG` at runtime no longer enables traces). The output format changes accordingly, from `java-caller <message> +1ms` to `JAVA-CALLER <pid>: <message>`.
+- **Breaking**: Minimum supported Node.js version is now 18 (`engines` previously declared `>=12`, while `njre` v3 already required `>=18`)
+- Reduce runtime dependencies from 17 packages to 10: remove `fs-extra` (replaced by `node:fs`) and `debug` (replaced by `node:util`), and upgrade `yauzl` so it no longer pulls `buffer-crc32`. Only `njre` and `semver` remain as direct dependencies.
+- Remove the `which` dev dependency, whose `engines` excluded the Node versions tested in CI
+- Fix `npm run lint`, broken since the ESLint v10 upgrade: `@eslint/js` and `globals` are required by `eslint.config.js` but were no longer installed transitively. They are now explicit dev dependencies, and CI runs `npm run lint` so the script cannot silently break again.
+
 ## [5.0.0] 2026-06-30
 
 - **Breaking**: Upgrade `njre` to v2.0.0: auto-installed JDK/JRE now comes from Eclipse Temurin (`api.adoptium.net`) instead of the deprecated AdoptOpenJDK endpoint (which hung under Node 24)

CLAUDE.md

@@ -9,8 +9,8 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 ## Commands
 
 ```shell
-npm run test                  # Run all mocha tests (timeout 300000ms; CI sets DEBUG=java-caller,njre)
-npm run test:debug            # Tests with DEBUG=java-caller enabled
+npm run test                  # Run all mocha tests (timeout 300000ms; CI sets NODE_DEBUG=java-caller)
+npm run test:debug            # Tests with NODE_DEBUG=java-caller enabled
 npm run lint:fix              # eslint --fix on **/*.js, then prettier on lib (tab-width 4, print-width 150)
 
 # Run a single test by name (mocha grep on the it()/describe() title):
@@ -50,10 +50,12 @@ Three modules in `lib/`, re-exported from `index.js`:
 - **Java-version resolution is cached on `globalThis.JAVA_CALLER_VERSIONS_CACHE`** to avoid repeated lookups across instances in one process. Tests reset this in `test/helpers/init.js`; if you add caching state, reset it there too.
 - **Platform branching** lives in `getPlatformBinPath()` (darwin = `Contents/Home/bin`) and several `os.platform() === "win32"` checks. Windows also handles arg quoting (`windowsVerbatimArguments`), `javaw` for windowless, and `windowsHide`. Any new behavior must be validated on win32/darwin/linux.
 - **`classPath`** accepts a string (split on `:`, converted to the OS delimiter) or a string array; resolved against `rootPath` unless `useAbsoluteClassPaths` is set.
+- **Runtime dependencies are deliberately minimal** (`njre` + `semver` only): prefer `node:` built-ins over adding a package.
+- **Debug traces use `util.debuglog`**, activated with `NODE_DEBUG=java-caller` (not `DEBUG=`, which was the pre-v6 `debug` package contract). `debuglog` reads `NODE_DEBUG` only from the environment the process was launched with, so tests and helpers cannot turn traces on at runtime — `npm run test:debug` sets it on the command line.
 
 ## Testing notes
 
 - Tests are mocha + `node:assert`, with shared helpers in `test/helpers/common.js` (`checkStatus`, `checkStdOutIncludes`, etc.) and per-run init in `test/helpers/init.js` (loaded via the `mocha.require` config in `package.json`).
 - `test/java-install.test.js` exercises the real `njre` download/install path, which is why the mocha timeout is 5 minutes.
-- CI (`.github/workflows/test.yml`) runs the matrix Node 18/20/24 × Java 8/11/17/21/25 × ubuntu/macos/windows, plus a no-Java job (`Test - No Java`) that runs the suite in a container without a system JDK.
+- CI (`.github/workflows/test.yml`) runs the matrix Node 18/20/24 × Java 8/11/17/21/25 × ubuntu/macos/windows, plus a no-Java job (`Test - No Java`) that runs the suite in a container without a system JDK, plus a `Lint` job running `npm run lint`.
 - macOS defaults `minimumJavaVersion` to 11 (no Java 8 there); keep that branch intact.

README.md

@@ -170,13 +170,15 @@ You can see **more examples in** [**test methods**](https://github.com/nvuillam/
 
 ## TROUBLESHOOTING
 
-Set environment variable `DEBUG=java-caller` before calling your code using java-caller module, and you will see the java commands executed.
+Set environment variable `NODE_DEBUG=java-caller` before calling your code using java-caller module, and you will see the java commands executed.
+
+> Since v6.0.0 traces use Node's built-in [`util.debuglog`](https://nodejs.org/api/util.html#utildebuglogsection-callback) instead of the `debug` package, so the variable is `NODE_DEBUG` and not `DEBUG` anymore. It must be set in the environment the process is launched with: setting `process.env.NODE_DEBUG` at runtime has no effect.
 
 Example debug log:
 
 ```shell
-java-caller Found Java version 1.80131 +1s
-java-caller Java command: java -Xms256m -Xmx2048m -cp C:\Work\gitPerso\node-java-caller\test\java\dist com.nvuillam.javacaller.JavaCallerTester -customarg nico +1ms
+JAVA-CALLER 12345: Found Java version 1.80131
+JAVA-CALLER 12345: Java command: java -Xms256m -Xmx2048m -cp C:\Work\gitPerso\node-java-caller\test\java\dist com.nvuillam.javacaller.JavaCallerTester -customarg nico
 ```
 
 ## CONTRIBUTE

examples/cli_app/package.json

@@ -12,9 +12,9 @@
   "scripts": {
     "install-local-cli": "npm install && npm link --force",
     "run:source": "node lib/index.js -a list --of arguments",
-    "run:source:verbose": "env DEBUG=java-caller node lib/index.js -a list --of arguments",
+    "run:source:verbose": "env NODE_DEBUG=java-caller node lib/index.js -a list --of arguments",
     "run:cli": "java-caller-example-cli -a list --of arguments",
-    "run:verbose": "env DEBUG=java-caller java-caller-example-cli -a list --of arguments"
+    "run:verbose": "env NODE_DEBUG=java-caller java-caller-example-cli -a list --of arguments"
   },
   "keywords": [
     "java-caller",

examples/module_app/package.json

@@ -12,9 +12,9 @@
   "scripts": {
     "install-local-cli": "npm install && npm link --force",
     "run:source": "node lib/index.js",
-    "run:source:verbose": "env DEBUG=java-caller node lib/index.js",
+    "run:source:verbose": "env NODE_DEBUG=java-caller node lib/index.js",
     "run:cli": "java-caller-example-module",
-    "run:cli:verbose": "env DEBUG=java-caller java-caller-example-module",
+    "run:cli:verbose": "env NODE_DEBUG=java-caller java-caller-example-module",
     "test": "echo \"I strongly encourage you to implement test cases and code coverage, with mocha and nyc for example :)\""
   },
   "keywords": [

lib/cli.js

@@ -1,6 +1,6 @@
 #! /usr/bin/env node
 const { JavaCaller } = require("./java-caller");
-const fse = require("fs-extra");
+const fs = require("fs");
 const path = require("path");
 
 class JavaCallerCli {
@@ -11,7 +11,7 @@ class JavaCallerCli {
     constructor(baseDir) {
         // Use user-defined JSON file to read configuration
         const configFile = path.resolve(`${baseDir}/java-caller-config.json`);
-        const options = fse.readJSONSync(configFile);
+        const options = JSON.parse(fs.readFileSync(configFile, "utf8"));
         // Default output is console with CLI
         if (options.output == null) {
             options.output = "console";

lib/java-caller.js

@@ -1,11 +1,15 @@
 #! /usr/bin/env node
-const debug = require("debug")("java-caller");
-const fse = require("fs-extra");
+const fs = require("fs");
 const os = require("os");
 const path = require("path");
+const { debuglog } = require("util");
 const { spawn } = require("child_process");
 const semver = require("semver");
 
+// NODE_DEBUG must be set in the environment the process is launched with:
+// debuglog never re-reads it, so setting process.env.NODE_DEBUG at runtime has no effect.
+const debug = debuglog("java-caller");
+
 class JavaCaller {
     "use strict";
     minimumJavaVersion = os.platform() === "darwin" ? 11 : 8; // Mac starts at 11
@@ -334,15 +338,15 @@ class JavaCaller {
             console.log(`Installing Java ${javaTypeToInstall} ${javaVersionToInstall} in ${this.javaCallerSupportDir}...`);
 
             // Create a directory for installing Java and ensure it contains a dummy package.json
-            await fse.ensureDir(this.javaCallerSupportDir, { mode: "0777" });
+            await fs.promises.mkdir(this.javaCallerSupportDir, { recursive: true, mode: "0777" });
             const packageJson = `${this.javaCallerSupportDir + path.sep}package.json`;
-            if (!fse.existsSync(packageJson)) {
+            if (!fs.existsSync(packageJson)) {
                 const packageJsonContent = {
                     name: "java-caller-support",
                     version: "1.0.0",
                     description: "Java installations by java-caller (https://github.com/nvuillam/node-java-caller)",
                 };
-                await fse.writeFile(packageJson, JSON.stringify(packageJsonContent), "utf8");
+                await fs.promises.writeFile(packageJson, JSON.stringify(packageJsonContent), "utf8");
             }
 
             // Install appropriate java version using njre
@@ -464,15 +468,15 @@ class JavaCaller {
     // check if one matches with javaType , minimumJavaVersion and maximumJavaVersion
     async findJavaVersionHome() {
         const javaInstallsTopDir = path.join(this.javaCallerSupportDir, "jre");
-        if (!fse.existsSync(javaInstallsTopDir)) {
+        if (!fs.existsSync(javaInstallsTopDir)) {
             return {};
         }
 
-        return await fse
+        return await fs.promises
             .readdir(javaInstallsTopDir)
             .then((items) =>
                 items
-                    .filter((item) => fse.statSync(path.join(javaInstallsTopDir, item)).isDirectory())
+                    .filter((item) => fs.statSync(path.join(javaInstallsTopDir, item)).isDirectory())
                     .map((folder) => {
                         const version = semver.coerce(folder);
                         return { version, folder };
@@ -483,7 +487,7 @@ class JavaCaller {
                         const bin = path.join(home, this.getPlatformBinPath());
                         return { version, folder, home, bin };
                     })
-                    .find(({ bin }) => fse.existsSync(bin)),
+                    .find(({ bin }) => fs.existsSync(bin)),
             )
             .then((match) => {
                 if (!match) return {};