Ensure incrementalMac consistency when exporting

ts/services/backups/export.ts

@@ -249,10 +249,7 @@ export class BackupExportStream extends Readable {
   readonly #serviceIdToRecipientId = new Map<string, number>();
   readonly #e164ToRecipientId = new Map<string, number>();
   readonly #roomIdToRecipientId = new Map<string, number>();
-  readonly #mediaNamesToLocatorInfos = new Map<
-    string,
-    Backups.FilePointer.ILocatorInfo
-  >();
+  readonly #mediaNamesToFilePointers = new Map<string, Backups.FilePointer>();
   readonly #stats: StatsType = {
     adHocCalls: 0,
     callLinks: 0,
@@ -355,7 +352,7 @@ export class BackupExportStream extends Readable {
   }
 
   public getMediaNamesIterator(): MapIterator<string> {
-    return this.#mediaNamesToLocatorInfos.keys();
+    return this.#mediaNamesToFilePointers.keys();
   }
 
   public getStats(): Readonly<StatsType> {
@@ -2608,16 +2605,17 @@ export class BackupExportStream extends Readable {
       const mediaName = getMediaNameForAttachment(attachment);
 
       // Re-use existing locatorInfo and backup job if we've already seen this file
-      const existingLocatorInfo = this.#mediaNamesToLocatorInfos.get(mediaName);
+      const existingFilePointer = this.#mediaNamesToFilePointers.get(mediaName);
 
-      if (existingLocatorInfo) {
-        filePointer.locatorInfo = existingLocatorInfo;
+      if (existingFilePointer?.locatorInfo) {
+        filePointer.locatorInfo = existingFilePointer.locatorInfo;
+        // Also copy over incrementalMac, since that depends on the encryption key
+        filePointer.incrementalMac = existingFilePointer.incrementalMac;
+        filePointer.incrementalMacChunkSize =
+          existingFilePointer.incrementalMacChunkSize;
       } else {
         if (filePointer.locatorInfo) {
-          this.#mediaNamesToLocatorInfos.set(
-            mediaName,
-            filePointer.locatorInfo
-          );
+          this.#mediaNamesToFilePointers.set(mediaName, filePointer);
         }
 
         if (backupJob) {

ts/services/backups/util/filePointers.ts

@@ -38,6 +38,7 @@ import {
   isValidAttachmentKey,
   isValidPlaintextHash,
 } from '../../../types/Crypto';
+import { isTestOrMockEnvironment } from '../../../environment';
 
 const log = createLogger('filePointers');
 
@@ -227,19 +228,18 @@ export async function getFilePointerForAttachment({
     height: attachment.height,
     caption: attachment.caption,
     blurHash: attachment.blurHash,
-
-    // Resilience to invalid data in the database from internal testing
-    ...(typeof attachment.incrementalMac === 'string' && attachment.chunkSize
-      ? {
-          incrementalMac: Bytes.fromBase64(attachment.incrementalMac),
-          incrementalMacChunkSize: attachment.chunkSize,
-        }
-      : {
-          incrementalMac: undefined,
-          incrementalMacChunkSize: undefined,
-        }),
   });
 
+  // TODO: DESKTOP-9112
+  if (isTestOrMockEnvironment()) {
+    // Check for string type for resilience to invalid data in the database from internal
+    // testing
+    if (typeof attachment.incrementalMac === 'string' && attachment.chunkSize) {
+      filePointer.incrementalMac = Bytes.fromBase64(attachment.incrementalMac);
+      filePointer.incrementalMacChunkSize = attachment.chunkSize;
+    }
+  }
+
   const locatorInfo = getLocatorInfoForAttachment({
     attachment,
     isLocalBackup,

ts/test-electron/backup/attachments_test.ts

@@ -100,12 +100,14 @@ describe('backup/attachments', () => {
       plaintextHash: Bytes.toHex(getRandomBytes(32)),
       key: Bytes.toBase64(generateKeys()),
       digest: Bytes.toBase64(getRandomBytes(32)),
-      size: 100,
+      size: 100 + index,
       contentType: IMAGE_JPEG,
       path: `/path/to/file${index}.png`,
       caption: `caption${index}`,
       localKey: Bytes.toBase64(generateAttachmentKeys()),
       uploadTimestamp: index,
+      incrementalMac: Bytes.toBase64(getRandomBytes(32)),
+      chunkSize: index * 128,
       thumbnail: {
         size: 1024,
         width: 150,
@@ -405,11 +407,10 @@ describe('backup/attachments', () => {
     it('deduplicates attachments on export based on mediaName', async () => {
       const attachment1 = composeAttachment(1);
       const attachment2 = {
-        ...attachment1,
-        contentType: IMAGE_WEBP,
-        caption: 'attachment2caption',
-        cdnKey: 'attachment2cdnkey',
-        cdnNumber: 25,
+        ...composeAttachment(2),
+        plaintextHash: attachment1.plaintextHash,
+        key: attachment1.key,
+        size: attachment1.size,
       };
 
       await asymmetricRoundtripHarness(
@@ -431,6 +432,9 @@ describe('backup/attachments', () => {
                 ...attachment2,
                 cdnKey: attachment1.cdnKey,
                 cdnNumber: attachment1.cdnNumber,
+                uploadTimestamp: attachment1.uploadTimestamp,
+                incrementalMac: attachment1.incrementalMac,
+                chunkSize: attachment1.chunkSize,
               }),
             ],
           }),