Handle early dependency cache failures during Java setup (#1226)

* Handle cache restore promise rejections

Validate dependency cache providers before Java installation and settle cache restore failures immediately while preserving setup error precedence.

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

* Make cache-rejection regression test deterministic

Reject the cache restore only after it has started and while the Java
installation is still pending, instead of relying on event-loop timing.
Verified the test fails against the pre-fix implementation.

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

* Validate cache input after required input checks

Move the package-manager validation out of the top of run() so that
missing java-version/java-version-file and toolchain id errors keep
their original precedence. Validation now happens immediately before
the cache restore is started, which still fails fast before any JDK
download.

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

---------

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

src/cache.ts

@@ -138,6 +138,10 @@ function findPackageManager(id: string): PackageManager {
   return packageManager;
 }
 
+export function validatePackageManager(id: string): void {
+  findPackageManager(id);
+}
+
 function resolveCachePaths(
   packageManager: PackageManager,
   cachePaths: string[]

src/setup-java.ts

@@ -37,7 +37,7 @@ export async function run() {
     core.getInput(constants.INPUT_VERIFY_SIGNATURE_PUBLIC_KEY) || undefined;
   const toolchainIds = core.getMultilineInput(constants.INPUT_MVN_TOOLCHAIN_ID);
   let actionError: Error | undefined;
-  let cacheRestore: Promise<void> | undefined;
+  let cacheRestore: Promise<PromiseSettledResult<void>> | undefined;
   const toolchainConfigurations: ToolchainConfiguration[] = [];
 
   try {
@@ -94,8 +94,9 @@ export async function run() {
         toolchainIds
       };
 
+      await validateCacheInput(cache);
       cacheRestore = cache
-        ? startCacheRestore(cache, cacheDependencyPath, cachePath)
+        ? settle(startCacheRestore(cache, cacheDependencyPath, cachePath))
         : undefined;
       toolchainConfigurations.push(
         await installVersion(versionInfo.version, installerInputsOptions)
@@ -120,8 +121,9 @@ export async function run() {
         toolchainIds
       };
 
+      await validateCacheInput(cache);
       cacheRestore = cache
-        ? startCacheRestore(cache, cacheDependencyPath, cachePath)
+        ? settle(startCacheRestore(cache, cacheDependencyPath, cachePath))
         : undefined;
       for (const [index, version] of versions.entries()) {
         toolchainConfigurations.push(
@@ -144,12 +146,9 @@ export async function run() {
   }
 
   if (cacheRestore) {
-    try {
-      await cacheRestore;
-    } catch (error) {
-      if (!actionError) {
-        actionError = error as Error;
-      }
+    const cacheResult = await cacheRestore;
+    if (cacheResult.status === 'rejected' && !actionError) {
+      actionError = cacheResult.reason as Error;
     }
   }
 
@@ -158,6 +157,21 @@ export async function run() {
   }
 }
 
+async function validateCacheInput(cache: string): Promise<void> {
+  if (!cache) {
+    return;
+  }
+  const {validatePackageManager} = await import('./cache.js');
+  validatePackageManager(cache);
+}
+
+function settle<T>(promise: Promise<T>): Promise<PromiseSettledResult<T>> {
+  return promise.then<PromiseFulfilledResult<T>, PromiseRejectedResult>(
+    value => ({status: 'fulfilled', value}),
+    reason => ({status: 'rejected', reason})
+  );
+}
+
 if (process.argv[1] === fileURLToPath(import.meta.url)) {
   run();
 } else {