Make the Adoptopenjdk package type look at the Temurin repo first for latest assets (#522)

* Make the Adoptopenjdk package type look at the Temurin repo first for latest assets

* Address Copilot code review comments

- Use strict equality (===, !==) instead of loose equality (==, !=) for all comparisons
- Properly handle caught errors with instanceof type narrowing before accessing properties
- Only fall back to legacy AdoptOpenJDK for specific version-not-found errors
- Rethrow unexpected errors to avoid masking real issues (network failures, rate limits, etc.)
- Fix error message check to match actual error text ('No matching version found')
- Remove unnecessary undefined check since method return type is never undefined
- Add @internal JSDoc annotation to TemurinDistribution.findPackageForDownload()
- Update tests to properly mock Temurin lookup failures for fallback behavior testing
- Rebuild dist files

* Always fall back to legacy AdoptOpenJDK but log all Temurin failures

- Change error handling to gracefully fall back for all errors, not just version-not-found
- Log version-not-found errors as notices with migration guidance
- Log other Temurin failures as debug messages for troubleshooting
- Improves resilience: users always get a result even if Temurin API has issues
- Maintains visibility: failures are still logged for debugging

* Fixes from review

* Fixes from review

* Fixes from review

* Regenerate dist

src/distributions/adopt/installer.ts

@@ -21,6 +21,7 @@ import {
   MAX_PAGINATION_PAGES,
   validatePaginationUrl
 } from '../../util';
+import {TemurinDistribution, TemurinImplementation} from '../temurin/installer';
 
 export enum AdoptImplementation {
   Hotspot = 'Hotspot',
@@ -28,15 +29,72 @@ export enum AdoptImplementation {
 }
 
 export class AdoptDistribution extends JavaBase {
+  private readonly temurinDistribution: TemurinDistribution | null;
+
   constructor(
     installerOptions: JavaInstallerOptions,
-    private readonly jvmImpl: AdoptImplementation
+    private readonly jvmImpl: AdoptImplementation,
+    temurinDistribution: TemurinDistribution | null = null
   ) {
     super(`Adopt-${jvmImpl}`, installerOptions);
+
+    if (
+      temurinDistribution !== null &&
+      jvmImpl !== AdoptImplementation.Hotspot
+    ) {
+      throw new Error('Only Hotspot JVM is supported by Temurin.');
+    }
+
+    // Only use the temurin repo for Hotspot JVMs
+    this.temurinDistribution =
+      temurinDistribution ??
+      (jvmImpl === AdoptImplementation.Hotspot
+        ? new TemurinDistribution(
+            installerOptions,
+            TemurinImplementation.Hotspot
+          )
+        : null);
   }
 
   protected async findPackageForDownload(
     version: string
+  ): Promise<JavaDownloadRelease> {
+    if (this.jvmImpl === AdoptImplementation.Hotspot) {
+      core.notice(
+        "AdoptOpenJDK has moved to Eclipse Temurin https://github.com/actions/setup-java#supported-distributions please consider changing to the 'temurin' distribution type in your setup-java configuration."
+      );
+    }
+
+    if (
+      this.jvmImpl === AdoptImplementation.Hotspot &&
+      this.temurinDistribution !== null
+    ) {
+      try {
+        return await this.temurinDistribution.findPackageForDownload(version);
+      } catch (error) {
+        // Log the failure but always fall back to legacy AdoptOpenJDK for resilience
+        const errorMessage =
+          error instanceof Error ? error.message : String(error);
+        if (error instanceof Error && error.name === 'VersionNotFoundError') {
+          core.notice(
+            'The JVM you are looking for could not be found in the Temurin repository, this likely indicates ' +
+              'that you are using an out of date version of Java, consider updating and moving to using the Temurin distribution type in setup-java.'
+          );
+        } else {
+          // Log other errors for debugging but gracefully fall back
+          core.debug(
+            `Temurin lookup failed: ${errorMessage}. Falling back to AdoptOpenJDK API.`
+          );
+        }
+      }
+    }
+
+    // failed to find a Temurin version, so fall back to AdoptOpenJDK
+    return this.findPackageForDownloadOldAdoptOpenJdk(version);
+  }
+
+  private async findPackageForDownloadOldAdoptOpenJdk(
+    version: string
   ): Promise<JavaDownloadRelease> {
     const availableVersionsRaw = await this.getAvailableVersions();
     const availableVersionsWithBinaries = availableVersionsRaw

src/distributions/base-installer.ts

@@ -292,7 +292,9 @@ export abstract class JavaBase {
       }
     }
 
-    return new Error(parts.join('\n'));
+    const error = new Error(parts.join('\n'));
+    error.name = 'VersionNotFoundError';
+    return error;
   }
 
   protected setJavaDefault(version: string, toolPath: string) {

src/distributions/temurin/installer.ts

@@ -34,7 +34,10 @@ export class TemurinDistribution extends JavaBase {
     super(`Temurin-${jvmImpl}`, installerOptions);
   }
 
-  protected async findPackageForDownload(
+  /**
+   * @internal For cross-distribution reuse only. Not intended as a public API.
+   */
+  public async findPackageForDownload(
     version: string
   ): Promise<JavaDownloadRelease> {
     const availableVersionsRaw = await this.getAvailableVersions();