Restore dependency and wrapper caches concurrently (#1174)

* Restore dependency and wrapper caches concurrently

Run primary dependency and wrapper cache restores in parallel while preserving existing outputs and save semantics.

Add unit and E2E coverage for concurrent restore behavior, wrapper cache validation, and additional-cache error handling.

Include a manual benchmark workflow for baseline-vs-candidate restore timing comparisons across OSes.

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

Copilot-Session: d43ec3dd-96c7-4eb3-909e-b8123cd12d3c

* Address PR review comments

Use env variables for cache-hit values in benchmark record steps to avoid expression expansion in run commands, and rename E2E restore step labels for clarity.

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

Copilot-Session: d43ec3dd-96c7-4eb3-909e-b8123cd12d3c

* Stabilize wrapper cache restore checks

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

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: d43ec3dd-96c7-4eb3-909e-b8123cd12d3c

src/cache.ts

@@ -36,6 +36,11 @@ interface AdditionalCache {
   pattern: string[];
 }
 
+interface PreparedAdditionalCache {
+  cache: AdditionalCache;
+  primaryKey: string;
+}
+
 interface PackageManager {
   id: 'maven' | 'gradle' | 'sbt';
   /**
@@ -189,11 +194,37 @@ async function computeAdditionalCacheKey(
  */
 export async function restore(id: string, cacheDependencyPath: string) {
   const packageManager = findPackageManager(id);
-  const primaryKey = await computeCacheKey(packageManager, cacheDependencyPath);
+  const [primaryKey, preparedAdditionalCaches] = await Promise.all([
+    computeCacheKey(packageManager, cacheDependencyPath),
+    prepareAdditionalCaches(packageManager.additionalCaches ?? [])
+  ]);
+
   core.debug(`primary key is ${primaryKey}`);
   core.saveState(STATE_CACHE_PRIMARY_KEY, primaryKey);
   core.setOutput(STATE_CACHE_PRIMARY_KEY, primaryKey);
 
+  for (const preparedCache of preparedAdditionalCaches) {
+    core.debug(
+      `${preparedCache.cache.name} primary key is ${preparedCache.primaryKey}`
+    );
+    core.saveState(
+      additionalCachePrimaryKeyState(preparedCache.cache.name),
+      preparedCache.primaryKey
+    );
+  }
+
+  await Promise.all([
+    restorePrimaryCache(packageManager, primaryKey),
+    ...preparedAdditionalCaches.map(preparedCache =>
+      restoreAdditionalCache(preparedCache)
+    )
+  ]);
+}
+
+async function restorePrimaryCache(
+  packageManager: PackageManager,
+  primaryKey: string
+) {
   // No "restoreKeys" is set, to start with a clear cache after dependency update (see https://github.com/actions/setup-java/issues/269)
   const matchedKey = await cache.restoreCache(packageManager.path, primaryKey);
   if (matchedKey) {
@@ -204,32 +235,39 @@ export async function restore(id: string, cacheDependencyPath: string) {
     core.setOutput('cache-hit', false);
     core.info(`${packageManager.id} cache is not found`);
   }
-
-  for (const additionalCache of packageManager.additionalCaches ?? []) {
-    await restoreAdditionalCache(additionalCache);
-  }
 }
 
 /**
- * Restore an additional cache (e.g. a build-tool wrapper distribution) that is
- * keyed independently of the main dependency cache so that it survives changes
- * to volatile dependency files. Skips silently when the project does not use
- * the corresponding feature.
+ * Compute keys for additional caches (e.g. build-tool wrapper distributions).
+ * Additional caches without a matching configuration file are omitted.
  */
-async function restoreAdditionalCache(additionalCache: AdditionalCache) {
-  const primaryKey = await computeAdditionalCacheKey(additionalCache);
-  if (!primaryKey) {
-    core.debug(
-      `No file matched [${additionalCache.pattern}] for the ${additionalCache.name} cache, skipping.`
-    );
-    return;
-  }
-  core.debug(`${additionalCache.name} primary key is ${primaryKey}`);
-  core.saveState(
-    additionalCachePrimaryKeyState(additionalCache.name),
-    primaryKey
+async function prepareAdditionalCaches(
+  additionalCaches: AdditionalCache[]
+): Promise<PreparedAdditionalCache[]> {
+  const preparedCaches = await Promise.all(
+    additionalCaches.map(async additionalCache => {
+      const primaryKey = await computeAdditionalCacheKey(additionalCache);
+      if (!primaryKey) {
+        core.debug(
+          `No file matched [${additionalCache.pattern}] for the ${additionalCache.name} cache, skipping.`
+        );
+        return undefined;
+      }
+      return {cache: additionalCache, primaryKey};
+    })
   );
 
+  return preparedCaches.filter(
+    (preparedCache): preparedCache is PreparedAdditionalCache =>
+      preparedCache !== undefined
+  );
+}
+
+/**
+ * Restore an additional cache keyed independently of the main dependency cache.
+ */
+async function restoreAdditionalCache(preparedCache: PreparedAdditionalCache) {
+  const {cache: additionalCache, primaryKey} = preparedCache;
   const matchedKey = await cache.restoreCache(additionalCache.path, primaryKey);
   if (matchedKey) {
     core.saveState(
@@ -237,6 +275,8 @@ async function restoreAdditionalCache(additionalCache: AdditionalCache) {
       matchedKey
     );
     core.info(`${additionalCache.name} cache restored from key: ${matchedKey}`);
+  } else {
+    core.info(`${additionalCache.name} cache is not found`);
   }
 }
 
@@ -252,7 +292,14 @@ export async function save(id: string) {
   const primaryKey = core.getState(STATE_CACHE_PRIMARY_KEY);
 
   for (const additionalCache of packageManager.additionalCaches ?? []) {
-    await saveAdditionalCache(packageManager, additionalCache);
+    try {
+      await saveAdditionalCache(packageManager, additionalCache);
+    } catch (error) {
+      const err = error as Error;
+      core.warning(
+        `Failed to save ${additionalCache.name} cache: ${err.message}. Continuing with primary cache save.`
+      );
+    }
   }
 
   if (!primaryKey) {
@@ -360,7 +407,7 @@ async function saveAdditionalCache(
     } else {
       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.'
+          `Failed to save ${additionalCache.name} 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.`
         );
       }
       throw error;