From e4f09ac93d73d1c2a092b37f3f6f811545ac6feb Mon Sep 17 00:00:00 2001
From: David Stone <davidjamesstone@gmail.com>
Date: Tue, 31 Mar 2026 16:30:06 +0100
Subject: [PATCH 1/2] Change copyS3File to handle files that have already been
 persisted

---
 src/repositories/file-repository.js |  2 +-
 src/services/file-service.js        | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/repositories/file-repository.js b/src/repositories/file-repository.js
index a24f221..5a43ee8 100644
--- a/src/repositories/file-repository.js
+++ b/src/repositories/file-repository.js
@@ -62,7 +62,7 @@ export async function getByFileId(fileId) {
 
 /**
  * Updates the S3 Keys for a given set of files
- * @param {{ fileId: string; s3Bucket: string; oldS3Key: string; newS3Key: string; }[]} updateFiles
+ * @param {{ fileId: string; s3Bucket: string; oldS3Key: string | undefined; newS3Key: string; }[]} updateFiles
  * @param {ClientSession} session
  */
 export async function updateS3Keys(updateFiles, session) {
diff --git a/src/services/file-service.js b/src/services/file-service.js
index 352a655..0a09ee2 100644
--- a/src/services/file-service.js
+++ b/src/services/file-service.js
@@ -174,7 +174,7 @@ export async function persistFiles(files, persistedRetrievalKey) {
   const session = mongoClient.startSession()
 
   /**
-   * @type {Promise<{ fileId: string, s3Bucket: string; oldS3Key: string; newS3Key: string; }>[]}
+   * @type {Promise<{ fileId: string, s3Bucket: string; oldS3Key: string | undefined; newS3Key: string; }>[]}
    */
   let updateFiles = []
 
@@ -232,7 +232,7 @@ export async function persistFiles(files, persistedRetrievalKey) {
 
 /**
  * Deletes old files in staging based on the provided keys.
- * @param {Promise<{ fileId: string, s3Bucket: string; oldS3Key: string; newS3Key: string; }>[]} keys - an array of files to handle
+ * @param {Promise<{ fileId: string, s3Bucket: string; oldS3Key: string | undefined; newS3Key: string; }>[]} keys - an array of files to handle
  * @param {('oldS3Key'|'newS3Key')} lookupKey - the key to use to look up the S3 key
  * @param {S3Client} client - S3 client
  */
@@ -241,6 +241,7 @@ async function deleteOldFiles(keys, lookupKey, client) {
   const filteredKeys = settledKeys
     .filter((result) => result.status === 'fulfilled')
     .map((result) => result.value)
+    .filter((value) => value.oldS3Key !== undefined) // Filter out any undefined results (files that didn't need copying)
 
   // AWS do have the DeleteObjects command instead which would be preferable. However, S3 keys
   // are stored on a per-document basis not a global and so we can't batch these up in case of any
@@ -271,7 +272,16 @@ async function copyS3File(fileId, initiatedRetrievalKey, client) {
   }
 
   if (fileStatus.s3Key.startsWith(loadedPrefix)) {
-    throw Boom.badRequest(`File ID ${fileId} has already been persisted`)
+    const msg = `File ${fileId} is already in the loaded directory, no need to copy`
+
+    logger.info(`[copyS3File] ${msg}`)
+
+    return {
+      fileId,
+      s3Bucket: fileStatus.s3Bucket,
+      oldS3Key: undefined, // Marker to indicate no copy was needed
+      newS3Key: fileStatus.s3Key
+    }
   }
 
   const oldS3Key = fileStatus.s3Key

From 167f7318ea69c7ac7e3788509a22b872e50859ec Mon Sep 17 00:00:00 2001
From: David Stone <davidjamesstone@gmail.com>
Date: Tue, 31 Mar 2026 16:47:01 +0100
Subject: [PATCH 2/2] Add tests to copyS3File to handle files that have already
 been persisted

---
 src/services/file-service.test.js | 35 ++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/src/services/file-service.test.js b/src/services/file-service.test.js
index 92c9be2..af56b2a 100644
--- a/src/services/file-service.test.js
+++ b/src/services/file-service.test.js
@@ -886,7 +886,7 @@ describe('Files service', () => {
       })
     })
 
-    it('should not allow a previously extended file to be extended again', async () => {
+    it('should allow a previously extended file to be extended again', async () => {
       /** @type {FormFileUploadStatus} */
       const dummyData = {
         ...successfulFile,
@@ -897,20 +897,25 @@ describe('Files service', () => {
       jest.mocked(verify).mockResolvedValueOnce(true)
       jest.mocked(repository.getByFileId).mockResolvedValueOnce(dummyData)
 
-      await expect(
-        persistFiles(
-          [
-            {
-              fileId: dummyData.fileId,
-              initiatedRetrievalKey: dummyData.retrievalKey
-            }
-          ],
-          dummyData.retrievalKey
-        )
-      ).rejects.toThrow(
-        Boom.badRequest(
-          `File ID ${dummyData.fileId} has already been persisted`
-        )
+      jest.mocked(hash).mockResolvedValueOnce('caseSensitiveHash')
+      jest.mocked(verify).mockResolvedValueOnce(true)
+
+      await persistFiles(
+        [
+          {
+            fileId: dummyData.fileId,
+            initiatedRetrievalKey: dummyData.retrievalKey
+          }
+        ],
+        dummyData.retrievalKey
+      )
+
+      expect(hash).toHaveBeenCalledWith(dummyData.retrievalKey.toLowerCase())
+      expect(repository.updateRetrievalKeys).toHaveBeenCalledWith(
+        [dummyData.fileId],
+        'caseSensitiveHash',
+        false,
+        expect.any(Object)
       )
     })