feat: Add set-default option (#1017)

* Add set-default option

This option allows to install an additional JDK without making it the
default one.

I have wanted this for quite a long time as I'm running custom GitHub
Actions with Java, which might require a specific JDK and I don't want
to pollute the JDK that is used by the overall workflow calling the
action.
And I'm apparently not alone as there was a preexisting issue.

Fixes #560

* Dedupe setJavaDefault and document multi-version/toolchain behavior

- Refactor setJavaDefault to delegate shared output/env logic to
  setJavaEnvironment, avoiding duplication between the two.
- Document that set-default applies to all JDKs in a multiline
  java-version, and that installed JDKs remain registered in Maven
  toolchains regardless of set-default.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* test: fix Prettier formatting in base-installer test

Resolves the failing 'Basic validation / build' format-check on
__tests__/distributors/base-installer.test.ts (line exceeded print width).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Bruno Borges <brborges@microsoft.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/constants.ts

@@ -6,6 +6,7 @@ export const INPUT_JAVA_PACKAGE = 'java-package';
 export const INPUT_DISTRIBUTION = 'distribution';
 export const INPUT_JDK_FILE = 'jdkFile';
 export const INPUT_CHECK_LATEST = 'check-latest';
+export const INPUT_SET_DEFAULT = 'set-default';
 export const INPUT_VERIFY_SIGNATURE = 'verify-signature';
 export const INPUT_VERIFY_SIGNATURE_PUBLIC_KEY = 'verify-signature-public-key';
 export const INPUT_SERVER_ID = 'server-id';

src/distributions/base-installer.ts

@@ -20,6 +20,7 @@ export abstract class JavaBase {
   protected packageType: string;
   protected stable: boolean;
   protected checkLatest: boolean;
+  protected setDefault: boolean;
   protected verifySignature: boolean;
   protected verifySignaturePublicKey: string | undefined;
 
@@ -38,6 +39,10 @@ export abstract class JavaBase {
     this.architecture = installerOptions.architecture || os.arch();
     this.packageType = installerOptions.packageType;
     this.checkLatest = installerOptions.checkLatest;
+    this.setDefault =
+      installerOptions.setDefault !== undefined
+        ? installerOptions.setDefault
+        : true;
     this.verifySignature = installerOptions.verifySignature ?? false;
     this.verifySignaturePublicKey = installerOptions.verifySignaturePublicKey;
   }
@@ -179,8 +184,15 @@ export abstract class JavaBase {
       foundJava.path = macOSPostfixPath;
     }
 
-    core.info(`Setting Java ${foundJava.version} as the default`);
-    this.setJavaDefault(foundJava.version, foundJava.path);
+    if (this.setDefault) {
+      core.info(`Setting Java ${foundJava.version} as the default`);
+      this.setJavaDefault(foundJava.version, foundJava.path);
+    } else {
+      core.info(
+        `Installing Java ${foundJava.version} (not setting as default)`
+      );
+      this.setJavaEnvironment(foundJava.version, foundJava.path);
+    }
 
     return foundJava;
   }
@@ -312,9 +324,13 @@ export abstract class JavaBase {
   }
 
   protected setJavaDefault(version: string, toolPath: string) {
-    const majorVersion = version.split('.')[0];
     core.exportVariable('JAVA_HOME', toolPath);
     core.addPath(path.join(toolPath, 'bin'));
+    this.setJavaEnvironment(version, toolPath);
+  }
+
+  protected setJavaEnvironment(version: string, toolPath: string) {
+    const majorVersion = version.split('.')[0];
     core.setOutput('distribution', this.distribution);
     core.setOutput('path', toolPath);
     core.setOutput('version', version);

src/distributions/base-models.ts

@@ -3,6 +3,7 @@ export interface JavaInstallerOptions {
   architecture: string;
   packageType: string;
   checkLatest: boolean;
+  setDefault?: boolean;
   verifySignature?: boolean;
   verifySignaturePublicKey?: string;
 }

src/distributions/local/installer.ts

@@ -69,9 +69,15 @@ export class LocalDistribution extends JavaBase {
       foundJava.path = macOSPostfixPath;
     }
 
-    core.info(`Setting Java ${foundJava.version} as default`);
-
-    this.setJavaDefault(foundJava.version, foundJava.path);
+    if (this.setDefault) {
+      core.info(`Setting Java ${foundJava.version} as the default`);
+      this.setJavaDefault(foundJava.version, foundJava.path);
+    } else {
+      core.info(
+        `Installing Java ${foundJava.version} (not setting as default)`
+      );
+      this.setJavaEnvironment(foundJava.version, foundJava.path);
+    }
     return foundJava;
   }
 

src/setup-java.ts

@@ -29,6 +29,7 @@ async function run() {
       constants.INPUT_CACHE_DEPENDENCY_PATH
     );
     const checkLatest = getBooleanInput(constants.INPUT_CHECK_LATEST, false);
+    const setDefault = getBooleanInput(constants.INPUT_SET_DEFAULT, true);
     const verifySignature = getBooleanInput(
       constants.INPUT_VERIFY_SIGNATURE,
       false
@@ -51,6 +52,7 @@ async function run() {
       architecture,
       packageType,
       checkLatest,
+      setDefault,
       verifySignature,
       verifySignaturePublicKey,
       distributionName,
@@ -110,6 +112,7 @@ async function installVersion(
     architecture,
     packageType,
     checkLatest,
+    setDefault,
     verifySignature,
     verifySignaturePublicKey,
     toolchainIds
@@ -119,6 +122,7 @@ async function installVersion(
     architecture,
     packageType,
     checkLatest,
+    setDefault,
     verifySignature,
     verifySignaturePublicKey,
     version
@@ -155,6 +159,7 @@ interface installerInputsOptions {
   architecture: string;
   packageType: string;
   checkLatest: boolean;
+  setDefault: boolean;
   verifySignature: boolean;
   verifySignaturePublicKey: string | undefined;
   distributionName: string;