Merge c30cb6d377 into 387ac29b30

On self-hosted runners toolchains.xml may survive multiple runs and unexpectedly
grow as a result of the toolchains setup simply appending the JDK definition
even if one with the same `type` and `provides.id` already exists.

Restructuring the parsing step and filtering the potentially existing list of
toolchain definitions prevents this and also fixes toolchain.xml files that
already contain duplicates.

Fixes #530

.github/workflows/basic-validation.yml

@@ -15,3 +15,5 @@ jobs:
   call-basic-validation:
     name: Basic validation
     uses: actions/reusable-workflows/.github/workflows/basic-validation.yml@main
+    with:
+      node-version: '20.x'

.github/workflows/check-dist.yml

@@ -15,3 +15,5 @@ jobs:
   call-check-dist:
     name: Check dist/
     uses: actions/reusable-workflows/.github/workflows/check-dist.yml@main
+    with:
+      node-version: '20.x'

__tests__/toolchains.test.ts

@@ -143,7 +143,20 @@ describe('toolchains tests', () => {
         </toolchain>
       </toolchains>`;
     const result = `<?xml version="1.0"?>
-<toolchains>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
   <toolchain>
     <type>jdk</type>
     <provides>
@@ -155,6 +168,442 @@ describe('toolchains tests', () => {
       <jdkHome>/opt/jdk/sun/1.6</jdkHome>
     </configuration>
   </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('does not discard custom elements in existing toolchain definitions', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+        <toolchain>
+          <type>jdk</type>
+          <provides>
+            <version>1.6</version>
+            <vendor>Sun</vendor>
+            <id>sun_1.6</id>
+            <custom>foo</custom>
+          </provides>
+          <configuration>
+            <jdkHome>/opt/jdk/sun/1.6</jdkHome>
+            <fooHome>/usr/local/bin/bash</fooHome>
+          </configuration>
+        </toolchain>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>1.6</version>
+      <vendor>Sun</vendor>
+      <id>sun_1.6</id>
+      <custom>foo</custom>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/jdk/sun/1.6</jdkHome>
+      <fooHome>/usr/local/bin/bash</fooHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('does not discard existing, custom toolchain definitions', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+        <toolchain>
+            <type>foo</type>
+            <provides>
+                <custom>baz</custom>
+            </provides>
+            <configuration>
+                <fooHome>/usr/local/bin/foo</fooHome>
+            </configuration>
+        </toolchain>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+  <toolchain>
+    <type>foo</type>
+    <provides>
+      <custom>baz</custom>
+    </provides>
+    <configuration>
+      <fooHome>/usr/local/bin/foo</fooHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('does not duplicate existing toolchain definitions', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+      <toolchain>
+        <type>jdk</type>
+        <provides>
+          <version>17</version>
+          <vendor>Eclipse Temurin</vendor>
+          <id>temurin_17</id>
+        </provides>
+        <configuration>
+          <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+        </configuration>
+      </toolchain>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('does not duplicate existing toolchain definitions if multiple exist', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+        <toolchain>
+          <type>jdk</type>
+          <provides>
+            <version>1.6</version>
+            <vendor>Sun</vendor>
+            <id>sun_1.6</id>
+          </provides>
+          <configuration>
+            <jdkHome>/opt/jdk/sun/1.6</jdkHome>
+          </configuration>
+        </toolchain>
+      <toolchain>
+        <type>jdk</type>
+        <provides>
+          <version>17</version>
+          <vendor>Eclipse Temurin</vendor>
+          <id>temurin_17</id>
+        </provides>
+        <configuration>
+          <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+        </configuration>
+      </toolchain>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>1.6</version>
+      <vendor>Sun</vendor>
+      <id>sun_1.6</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/jdk/sun/1.6</jdkHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('handles an empty list of existing toolchains correctly', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('handles an empty existing toolchains.xml correctly', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = ``;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
   <toolchain>
     <type>jdk</type>
     <provides>

action.yml

@@ -81,6 +81,6 @@ outputs:
   cache-hit:
     description: 'A boolean value to indicate an exact match was found for the primary key'
 runs:
-  using: 'node16'
+  using: 'node20'
   main: 'dist/setup/index.js'
   post: 'dist/cleanup/index.js'

package.json

@@ -1,6 +1,6 @@
 {
   "name": "setup-java",
-  "version": "3.4.1",
+  "version": "4.0.0",
   "private": true,
   "description": "setup java action",
   "main": "dist/setup/index.js",
@@ -29,28 +29,33 @@
     "@actions/cache": "^3.0.4",
     "@actions/core": "^1.10.0",
     "@actions/exec": "^1.0.4",
-    "@actions/glob": "^0.2.0",
+    "@actions/glob": "^0.4.0",
-    "@actions/http-client": "^1.0.11",
+    "@actions/http-client": "^2.2.0",
     "@actions/io": "^1.0.2",
-    "@actions/tool-cache": "^1.6.1",
+    "@actions/tool-cache": "^2.0.1",
     "semver": "^7.3.4",
     "xmlbuilder2": "^2.4.0"
   },
   "devDependencies": {
-    "@types/jest": "^27.0.2",
+    "@types/jest": "^29.5.9",
-    "@types/node": "^16.11.25",
+    "@types/node": "^20.9.3",
     "@types/semver": "^7.3.4",
     "@typescript-eslint/eslint-plugin": "^5.54.0",
     "@typescript-eslint/parser": "^5.54.0",
-    "@vercel/ncc": "^0.33.4",
+    "@vercel/ncc": "^0.38.1",
     "eslint": "^8.35.0",
     "eslint-config-prettier": "^8.6.0",
     "eslint-plugin-jest": "^27.2.1",
     "eslint-plugin-node": "^11.1.0",
-    "jest": "^27.5.1",
+    "jest": "^29.7.0",
-    "jest-circus": "^27.5.1",
+    "jest-circus": "^29.7.0",
     "prettier": "^2.8.4",
-    "ts-jest": "^27.0.5",
+    "ts-jest": "^29.1.1",
-    "typescript": "^4.2.3"
+    "typescript": "^5.3.2"
-  }
+  },
+  "bugs": {
+    "url": "https://github.com/actions/setup-java/issues"
+  },
+  "homepage": "https://github.com/actions/setup-java#readme"
+  
 }

src/cache.ts

@@ -149,10 +149,12 @@ export async function save(id: string) {
     await cache.saveCache(packageManager.path, primaryKey);
     core.info(`Cache saved with the key: ${primaryKey}`);
   } catch (error) {
-    if (error.name === cache.ReserveCacheError.name) {
+    const err = error as Error;
-      core.info(error.message);
+
+    if (err.name === cache.ReserveCacheError.name) {
+      core.info(err.message);
     } else {
-      if (isProbablyGradleDaemonProblem(packageManager, error)) {
+      if (isProbablyGradleDaemonProblem(packageManager, err)) {
         core.warning(
           'Failed to save Gradle cache on Windows. If tar.exe reported "Permission denied", try to run Gradle with `--no-daemon` option. Refer to https://github.com/actions/cache/issues/454 for details.'
         );

src/cleanup-java.ts

@@ -13,7 +13,9 @@ async function removePrivateKeyFromKeychain() {
       );
       await gpg.deleteKey(keyFingerprint);
     } catch (error) {
-      core.setFailed(`Failed to remove private key due to: ${error.message}`);
+      core.setFailed(
+        `Failed to remove private key due to: ${(error as Error).message}`
+      );
     }
   }
 }

src/distributions/dragonwell/installer.ts

@@ -206,7 +206,9 @@ export class DragonwellDistribution extends JavaBase {
       return fetchedDragonwellJson;
     } catch (err) {
       core.debug(
-        `Fetching Dragonwell versions info from the primary link: ${primaryUrl} ended up with the error: ${err.message}`
+        `Fetching Dragonwell versions info from the primary link: ${primaryUrl} ended up with the error: ${
+          (err as Error).message
+        }`
       );
       return null;
     }
@@ -232,7 +234,9 @@ export class DragonwellDistribution extends JavaBase {
       return fetchedDragonwellJson;
     } catch (err) {
       core.debug(
-        `Fetching Dragonwell versions info from the backup url: ${backupUrl} ended up with the error: ${err.message}`
+        `Fetching Dragonwell versions info from the backup url: ${backupUrl} ended up with the error: ${
+          (err as Error).message
+        }`
       );
       return null;
     }

src/distributions/microsoft/installer.ts

@@ -13,7 +13,7 @@ import * as core from '@actions/core';
 import * as tc from '@actions/tool-cache';
 import fs from 'fs';
 import path from 'path';
-import {ITypedResponse} from '@actions/http-client/interfaces';
+import {TypedResponse} from '@actions/http-client/lib/interfaces';
 
 export class MicrosoftDistributions extends JavaBase {
   constructor(installerOptions: JavaInstallerOptions) {
@@ -99,7 +99,7 @@ export class MicrosoftDistributions extends JavaBase {
 
     const headers = getGitHubHttpHeaders();
 
-    let response: ITypedResponse<tc.IToolRelease[]> | null = null;
+    let response: TypedResponse<tc.IToolRelease[]> | null = null;
 
     if (core.isDebug()) {
       console.time('Retrieving available versions for Microsoft took'); // eslint-disable-line no-console

src/setup-java.ts

@@ -79,7 +79,7 @@ async function run() {
       await restore(cache, cacheDependencyPath);
     }
   } catch (error) {
-    core.setFailed(error.message);
+    core.setFailed((error as Error).message);
   }
 }
 

src/toolchains.ts

@@ -84,47 +84,59 @@ export function generateToolchainDefinition(
   id: string,
   jdkHome: string
 ) {
-  let xmlObj;
+  let jsToolchains: Toolchain[] = [
-  if (original?.length) {
+    {
-    xmlObj = xmlCreate(original)
+      type: 'jdk',
-      .root()
+      provides: {
-      .ele({
+        version: `${version}`,
-        toolchain: {
+        vendor: `${vendor}`,
-          type: 'jdk',
+        id: `${id}`
-          provides: {
+      },
-            version: `${version}`,
+      configuration: {
-            vendor: `${vendor}`,
+        jdkHome: `${jdkHome}`
-            id: `${id}`
-          },
-          configuration: {
-            jdkHome: `${jdkHome}`
-          }
-        }
-      });
-  } else
-    xmlObj = xmlCreate({
-      toolchains: {
-        '@xmlns': 'http://maven.apache.org/TOOLCHAINS/1.1.0',
-        '@xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
-        '@xsi:schemaLocation':
-          'http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd',
-        toolchain: [
-          {
-            type: 'jdk',
-            provides: {
-              version: `${version}`,
-              vendor: `${vendor}`,
-              id: `${id}`
-            },
-            configuration: {
-              jdkHome: `${jdkHome}`
-            }
-          }
-        ]
       }
-    });
+    }
+  ];
+  if (original?.length) {
+    // convert existing toolchains into TS native objects for better handling
+    // xmlbuilder2 will convert the document into a `{toolchains: { toolchain: [] | {} }}` structure
+    // instead of the desired `toolchains: [{}]` one or simply `[{}]`
+    const jsObj = xmlCreate(original)
+      .root()
+      .toObject() as unknown as ExtractedToolchains;
+    if (jsObj.toolchains && jsObj.toolchains.toolchain) {
+      // in case only a single child exists xmlbuilder2 will not create an array and using verbose = true equally doesn't work here
+      // See https://oozcitak.github.io/xmlbuilder2/serialization.html#js-object-and-map-serializers for details
+      if (Array.isArray(jsObj.toolchains.toolchain)) {
+        jsToolchains.push(...jsObj.toolchains.toolchain);
+      } else {
+        jsToolchains.push(jsObj.toolchains.toolchain);
+      }
+    }
 
-  return xmlObj.end({
+    // remove potential duplicates based on type & id (which should be a unique combination);
+    // self.findIndex will only return the first occurrence, ensuring duplicates are skipped
+    jsToolchains = jsToolchains.filter(
+      (value, index, self) =>
+        // ensure non-jdk toolchains are kept in the results, we must not touch them because they belong to the user
+        value.type !== 'jdk' ||
+        index ===
+          self.findIndex(
+            t => t.type === value.type && t.provides.id === value.provides.id
+          )
+    );
+  }
+
+  // TODO: technically bad because we shouldn't re-create the toolchains root node (with possibly different schema values) if it already exists, however, just overriding the toolchain array with xmlbuilder2 is … uh non-trivial
+  return xmlCreate({
+    toolchains: {
+      '@xmlns': 'http://maven.apache.org/TOOLCHAINS/1.1.0',
+      '@xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
+      '@xsi:schemaLocation':
+        'http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd',
+      toolchain: jsToolchains
+    }
+  }).end({
     format: 'xml',
     wellFormed: false,
     headless: false,
@@ -167,3 +179,22 @@ async function writeToolchainsFileToDisk(
     flag: 'w'
   });
 }
+
+interface ExtractedToolchains {
+  toolchains: {
+    toolchain: Toolchain[] | Toolchain;
+  };
+}
+
+// Toolchain type definition according to Maven Toolchains XSD 1.1.0
+interface Toolchain {
+  type: string;
+  provides:
+    | {
+        version: string;
+        vendor: string;
+        id: string;
+      }
+    | any;
+  configuration: any;
+}