Ensure disk cache root exists

The disk cache root directory was previously being manually created in two places before creating the disk cache client. This CL instead ensures that the disk cache root directory is created when createDiskCache() is called, and simplifies the other callsites.

This fixes an issue where the disk cache directory might not exist if using --digest_function=BLAKE3.

Closes bazelbuild#19202.

PiperOrigin-RevId: 555429326
Change-Id: Ifcfa8c686df30c03c9fca24be860b2db780a6374

src/main/java/com/google/devtools/build/lib/remote/RemoteCacheClientFactory.java

@@ -139,10 +139,7 @@ private static DiskCacheClient createDiskCache(
       throws IOException {
     Path cacheDir =
         workingDirectory.getRelative(Preconditions.checkNotNull(diskCachePath, "diskCachePath"));
-    if (!cacheDir.exists()) {
-      cacheDir.createDirectoryAndParents();
-    }
-    return new DiskCacheClient(cacheDir, verifyDownloads, checkActionResult, digestUtil);
+    return new DiskCacheClient(cacheDir, verifyDownloads, digestUtil);
   }
 
   private static RemoteCacheClient createDiskAndHttpCache(
@@ -153,13 +150,7 @@ private static RemoteCacheClient createDiskAndHttpCache(
       AuthAndTLSOptions authAndTlsOptions,
       DigestUtil digestUtil)
       throws IOException {
-    Path cacheDir =
-        workingDirectory.getRelative(Preconditions.checkNotNull(diskCachePath, "diskCachePath"));
-    if (!cacheDir.exists()) {
-      cacheDir.createDirectoryAndParents();
-    }
-
-    RemoteCacheClient httpCache = createHttp(options, cred, authAndTlsOptions, digestUtil);
+    RemoteCacheClient httpCache = createHttp(options, cred, authAndTlsOptions, digestUtil, retrier);
     return createDiskAndRemoteClient(
         workingDirectory,
         diskCachePath,

src/main/java/com/google/devtools/build/lib/remote/disk/DiskCacheClient.java

@@ -58,8 +58,8 @@ public class DiskCacheClient implements RemoteCacheClient {
    * @param checkActionResult whether check referenced blobs exist in CAS when checking AC. If this
    *     is {@code true} and blobs referenced by the AC are missing, ignore the AC.
    */
-  public DiskCacheClient(
-      Path root, boolean verifyDownloads, boolean checkActionResult, DigestUtil digestUtil) {
+  public DiskCacheClient(Path root, boolean verifyDownloads, DigestUtil digestUtil)
+      throws IOException {
     this.verifyDownloads = verifyDownloads;
     this.checkActionResult = checkActionResult;
     this.digestUtil = digestUtil;
@@ -71,6 +71,8 @@ public DiskCacheClient(
           root.getChild(
               Ascii.toLowerCase(digestUtil.getDigestFunction().getValueDescriptor().getName()));
     }
+
+    this.root.createDirectoryAndParents();
   }
 
   /** Returns {@code true} if the provided {@code key} is stored in the CAS. */

src/tools/remote/src/main/java/com/google/devtools/build/remote/worker/OnDiskBlobStoreCache.java

@@ -43,7 +43,8 @@ class OnDiskBlobStoreCache extends RemoteCache {
           .setSymlinkAbsolutePathStrategy(SymlinkAbsolutePathStrategy.Value.ALLOWED)
           .build();
 
-  public OnDiskBlobStoreCache(RemoteOptions options, Path cacheDir, DigestUtil digestUtil) {
+  public OnDiskBlobStoreCache(RemoteOptions options, Path cacheDir, DigestUtil digestUtil)
+      throws IOException {
     super(
         CAPABILITIES,
         new DiskCacheClient(