From f21fb6abab93908b69e1c064369e2ec0b29d9d3d Mon Sep 17 00:00:00 2001
From: Thiyagu K <thiyaguk@google.com>
Date: Fri, 6 Mar 2026 13:50:11 +0000
Subject: [PATCH 1/2] fix-Set crc32c as the default option

---
 handwritten/storage/src/transfer-manager.ts  | 16 +++---
 handwritten/storage/test/transfer-manager.ts | 57 ++++++++++++++++++++
 2 files changed, 67 insertions(+), 6 deletions(-)

diff --git a/handwritten/storage/src/transfer-manager.ts b/handwritten/storage/src/transfer-manager.ts
index be34c76f08e..8b46a849bed 100644
--- a/handwritten/storage/src/transfer-manager.ts
+++ b/handwritten/storage/src/transfer-manager.ts
@@ -127,7 +127,7 @@ export interface UploadFileInChunksOptions {
   uploadId?: string;
   autoAbortFailure?: boolean;
   partsMap?: Map<number, string>;
-  validation?: 'md5' | false;
+  validation?: 'md5' | 'crc32c' | false;
   headers?: {[key: string]: string};
 }
 
@@ -140,7 +140,7 @@ export interface MultiPartUploadHelper {
   uploadPart(
     partNumber: number,
     chunk: Buffer,
-    validation?: 'md5' | false,
+    validation?: 'md5' | 'crc32c' | false,
   ): Promise<void>;
   completeUpload(): Promise<GaxiosResponse | undefined>;
   abortUpload(): Promise<void>;
@@ -289,7 +289,7 @@ class XMLMultiPartUploadHelper implements MultiPartUploadHelper {
   async uploadPart(
     partNumber: number,
     chunk: Buffer,
-    validation?: 'md5' | false,
+    validation?: 'md5' | 'crc32c' | false,
   ): Promise<void> {
     const url = `${this.baseUrl}?partNumber=${partNumber}&uploadId=${this.uploadId}`;
     let headers: Headers = this.#setGoogApiClientHeaders();
@@ -299,6 +299,10 @@ class XMLMultiPartUploadHelper implements MultiPartUploadHelper {
       headers = {
         'Content-MD5': hash,
       };
+    } else if (validation === 'crc32c') {
+      const crc = new CRC32C();
+      crc.update(chunk);
+      headers['x-goog-hash'] = `crc32c=${crc.toString()}`;
     }
 
     return AsyncRetry(async bail => {
@@ -806,6 +810,8 @@ export class TransferManager {
     );
     let partNumber = 1;
     let promises: Promise<void>[] = [];
+    const validation =
+      options.validation === undefined ? 'crc32c' : options.validation;
     try {
       if (options.uploadId === undefined) {
         await mpuHelper.initiateUpload(options.headers);
@@ -823,9 +829,7 @@ export class TransferManager {
           promises = [];
         }
         promises.push(
-          limit(() =>
-            mpuHelper.uploadPart(partNumber++, curChunk, options.validation),
-          ),
+          limit(() => mpuHelper.uploadPart(partNumber++, curChunk, validation))
         );
       }
       await Promise.all(promises);
diff --git a/handwritten/storage/test/transfer-manager.ts b/handwritten/storage/test/transfer-manager.ts
index 2582782fa7a..de0284ceb9a 100644
--- a/handwritten/storage/test/transfer-manager.ts
+++ b/handwritten/storage/test/transfer-manager.ts
@@ -730,5 +730,62 @@ describe('Transfer Manager', () => {
 
       assert(called);
     });
+
+    it('should use CRC32C validation when specified', async () => {
+      mockGeneratorFunction = (bucket, fileName, uploadId, partsMap) => {
+        fakeHelper = sandbox.createStubInstance(FakeXMLHelper);
+        fakeHelper.uploadId = uploadId || '';
+        fakeHelper.partsMap = partsMap || new Map<number, string>();
+        fakeHelper.initiateUpload.resolves();
+        fakeHelper.uploadPart.callsFake((partNumber, chunk, validation) => {
+          assert.strictEqual(validation, 'crc32c');
+
+          return Promise.resolve();
+        });
+        fakeHelper.completeUpload.resolves();
+        fakeHelper.abortUpload.resolves();
+        return fakeHelper;
+      };
+
+      await transferManager.uploadFileInChunks(
+        filePath,
+        {validation: 'crc32c'},
+        mockGeneratorFunction
+      );
+
+      assert.strictEqual(fakeHelper.uploadPart.calledOnce, true);
+    });
+
+    it('should apply crc32c validation by default', async () => {
+      let assertionMade = false;
+
+      mockGeneratorFunction = (bucket, fileName, uploadId, partsMap) => {
+        fakeHelper = sandbox.createStubInstance(FakeXMLHelper);
+        fakeHelper.uploadId = uploadId || '';
+        fakeHelper.partsMap = partsMap || new Map<number, string>();
+        fakeHelper.initiateUpload.resolves();
+
+        fakeHelper.uploadPart.callsFake((partNumber, chunk, validation) => {
+          // Confirm the validation is set to 'crc32c' by default.
+          assert.strictEqual(validation, 'crc32c');
+          assertionMade = true;
+          return Promise.resolve();
+        });
+
+        fakeHelper.completeUpload.resolves();
+        fakeHelper.abortUpload.resolves();
+        return fakeHelper;
+      };
+
+      // Call the function without specifying any validation option.
+      await transferManager.uploadFileInChunks(
+        filePath,
+        {},
+        mockGeneratorFunction
+      );
+
+      assert.strictEqual(fakeHelper.uploadPart.calledOnce, true);
+      assert.strictEqual(assertionMade, true);
+    });
   });
 });

From e26c2c51cc2433e8255a03c6c40f4c9cca1e3851 Mon Sep 17 00:00:00 2001
From: Thiyagu K <thiyaguk@google.com>
Date: Tue, 10 Mar 2026 13:58:26 +0530
Subject: [PATCH 2/2] code fix

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 handwritten/storage/src/transfer-manager.ts | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/handwritten/storage/src/transfer-manager.ts b/handwritten/storage/src/transfer-manager.ts
index 8b46a849bed..47a76296028 100644
--- a/handwritten/storage/src/transfer-manager.ts
+++ b/handwritten/storage/src/transfer-manager.ts
@@ -810,8 +810,7 @@ export class TransferManager {
     );
     let partNumber = 1;
     let promises: Promise<void>[] = [];
-    const validation =
-      options.validation === undefined ? 'crc32c' : options.validation;
+    const validation = options.validation ?? 'crc32c';
     try {
       if (options.uploadId === undefined) {
         await mpuHelper.initiateUpload(options.headers);