From fd1ecbbee8c7fa8fdf888c2f593f12d21b58b24c Mon Sep 17 00:00:00 2001
From: drive <drive@proton.ch>
Date: Thu, 7 May 2026 21:54:24 +0000
Subject: [PATCH] Fix upload failing to resume when blocks were uploaded out of
 order

---
 .../Proton.Drive.Sdk/Nodes/TransferQueue.cs   | 21 ++++++++++---------
 .../Nodes/Upload/RevisionWriter.cs            |  2 +-
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/cs/sdk/src/Proton.Drive.Sdk/Nodes/TransferQueue.cs b/cs/sdk/src/Proton.Drive.Sdk/Nodes/TransferQueue.cs
index ead6b27c..f1b2e853 100644
--- a/cs/sdk/src/Proton.Drive.Sdk/Nodes/TransferQueue.cs
+++ b/cs/sdk/src/Proton.Drive.Sdk/Nodes/TransferQueue.cs
@@ -86,7 +86,10 @@ internal sealed partial class TransferQueue(int maxDegreeOfParallelism, ILogger
         return queuePosition;
     }
 
-    public void SetFileTotalBlockCount(long queueToken, int total)
+    /// <summary>
+    /// Increases the total and remaining block counts for a file if the given total is greater than the current one.
+    /// </summary>
+    public void ApplyFileMinimumTotalBlockCount(long queueToken, int total)
     {
         lock (_fileBlocksLock)
         {
@@ -95,16 +98,14 @@ internal sealed partial class TransferQueue(int maxDegreeOfParallelism, ILogger
                 : throw new InvalidOperationException($"Queue token {queueToken} not found in transfer queue.");
 
             var delta = total - currentTotal;
+            if (delta <= 0)
+            {
+                return;
+            }
 
-            if (delta > 0)
-            {
-                FileQueueSemaphore.DecreaseCount(delta);
-                LogDecreasedFileQueueSemaphoreCount(delta, FileQueueSemaphore.CurrentCount);
-            }
-            else
-            {
-                RemoveBlocksFromFileQueue(-delta);
-            }
+            FileQueueSemaphore.DecreaseCount(delta);
+
+            LogDecreasedFileQueueSemaphoreCount(delta, FileQueueSemaphore.CurrentCount);
 
             _fileBlocks[queueToken] = (currentRemaining + delta, total);
         }
diff --git a/cs/sdk/src/Proton.Drive.Sdk/Nodes/Upload/RevisionWriter.cs b/cs/sdk/src/Proton.Drive.Sdk/Nodes/Upload/RevisionWriter.cs
index b5df09b2..e36bdba6 100644
--- a/cs/sdk/src/Proton.Drive.Sdk/Nodes/Upload/RevisionWriter.cs
+++ b/cs/sdk/src/Proton.Drive.Sdk/Nodes/Upload/RevisionWriter.cs
@@ -399,7 +399,7 @@ internal sealed partial class RevisionWriter
 
                 currentBlockNumber = newBlockNumber;
 
-                _client.UploadQueue.SetFileTotalBlockCount(_queueToken, currentBlockNumber.Value + expectedThumbnailBlockCount);
+                _client.UploadQueue.ApplyFileMinimumTotalBlockCount(_queueToken, currentBlockNumber.Value + expectedThumbnailBlockCount);
 
                 // ReSharper disable once PossiblyMistakenUseOfCancellationToken
                 await WaitForBlockUploaderAsync(uploadTasks, cancellationToken).ConfigureAwait(false);