Address cache.ts review feedback

- saveAdditionalCache: handle @actions/cache ValidationError (thrown when the
  cache paths do not resolve, e.g. the wrapper distribution was never
  downloaded) by skipping instead of failing the post step. Add a test.
- Point the Gradle wrapper cache comment at issue #269 (Gradle wrapper cache
  churn) instead of the Maven-specific #1095.

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

__tests__/cache.test.ts

@@ -570,6 +570,33 @@ describe('dependency cache', () => {
           expect.any(String)
         );
       });
+      it('does not fail the post step when the wrapper distribution path is missing', async () => {
+        createFile(join(workspace, 'pom.xml'));
+        (core.getState as jest.Mock<any>).mockImplementation((name: any) => {
+          switch (name) {
+            case 'cache-primary-key':
+              return 'setup-java-cache-primary-key';
+            case 'cache-matched-key':
+              return 'setup-java-cache-matched-key';
+            case 'cache-primary-key-maven-wrapper':
+              return 'setup-java-maven-wrapper-key';
+            default:
+              return '';
+          }
+        });
+        spyCacheSave.mockImplementation((paths: string[]) =>
+          paths.includes(join(os.homedir(), '.m2', 'wrapper', 'dists'))
+            ? Promise.reject(
+                new cache.ValidationError(
+                  'Path Validation Error: Path(s) specified in the action for caching do(es) not exist'
+                )
+              )
+            : Promise.resolve(0)
+        );
+
+        await expect(save('maven')).resolves.toBeUndefined();
+        expect(spyWarning).not.toHaveBeenCalled();
+      });
     });
     describe('for gradle', () => {
       it('uploads cache even if no build.gradle found', async () => {

dist/cleanup/index.js

@@ -99700,7 +99700,7 @@ const supportedPackageManager = [
         // The Gradle wrapper distribution only depends on the wrapper properties,
         // which change very rarely, so it is cached separately from the Gradle
         // caches. This keeps it available across the frequent *.gradle* changes
-        // that rotate the main cache key. See issue #1095.
+        // that rotate the main cache key. See issue #269.
         additionalCaches: [
             {
                 name: 'gradle-wrapper',
@@ -99900,6 +99900,13 @@ async function saveAdditionalCache(packageManager, additionalCache) {
     }
     catch (error) {
         const err = error;
+        if (err.name === ValidationError.name) {
+            // The cache paths did not resolve, e.g. the wrapper distribution was
+            // never downloaded because a system build tool was used or the download
+            // failed. Optional wrapper caches must not fail the post step, so skip.
+            core_debug(`${additionalCache.name} cache paths do not exist, not saving cache: ${err.message}`);
+            return;
+        }
         if (err.name === ReserveCacheError.name) {
             info(err.message);
         }

dist/setup/index.js

@@ -130922,7 +130922,7 @@ const supportedPackageManager = [
         // The Gradle wrapper distribution only depends on the wrapper properties,
         // which change very rarely, so it is cached separately from the Gradle
         // caches. This keeps it available across the frequent *.gradle* changes
-        // that rotate the main cache key. See issue #1095.
+        // that rotate the main cache key. See issue #269.
         additionalCaches: [
             {
                 name: 'gradle-wrapper',
@@ -131122,6 +131122,13 @@ async function saveAdditionalCache(packageManager, additionalCache) {
     }
     catch (error) {
         const err = error;
+        if (err.name === cache.ValidationError.name) {
+            // The cache paths did not resolve, e.g. the wrapper distribution was
+            // never downloaded because a system build tool was used or the download
+            // failed. Optional wrapper caches must not fail the post step, so skip.
+            core.debug(`${additionalCache.name} cache paths do not exist, not saving cache: ${err.message}`);
+            return;
+        }
         if (err.name === cache.ReserveCacheError.name) {
             core.info(err.message);
         }

src/cache.ts

@@ -85,7 +85,7 @@ const supportedPackageManager: PackageManager[] = [
     // The Gradle wrapper distribution only depends on the wrapper properties,
     // which change very rarely, so it is cached separately from the Gradle
     // caches. This keeps it available across the frequent *.gradle* changes
-    // that rotate the main cache key. See issue #1095.
+    // that rotate the main cache key. See issue #269.
     additionalCaches: [
       {
         name: 'gradle-wrapper',
@@ -333,6 +333,16 @@ async function saveAdditionalCache(
   } catch (error) {
     const err = error as Error;
 
+    if (err.name === cache.ValidationError.name) {
+      // The cache paths did not resolve, e.g. the wrapper distribution was
+      // never downloaded because a system build tool was used or the download
+      // failed. Optional wrapper caches must not fail the post step, so skip.
+      core.debug(
+        `${additionalCache.name} cache paths do not exist, not saving cache: ${err.message}`
+      );
+      return;
+    }
+
     if (err.name === cache.ReserveCacheError.name) {
       core.info(err.message);
     } else {