From 29dcac23cf239a166b93675430bcbb7c7b4c676e Mon Sep 17 00:00:00 2001
From: AsamK <asamk@gmx.de>
Date: Tue, 22 Sep 2026 21:04:34 +0200
Subject: [PATCH] Improve attachment download failure handling

Fixes #2116
---
 .../manager/helper/AttachmentHelper.java      |  2 +-
 .../manager/storage/AttachmentStore.java      | 23 ++++++++++++++++---
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/lib/src/main/java/org/asamk/signal/manager/helper/AttachmentHelper.java b/lib/src/main/java/org/asamk/signal/manager/helper/AttachmentHelper.java
index 85ea14a4..82d8a9c4 100644
--- a/lib/src/main/java/org/asamk/signal/manager/helper/AttachmentHelper.java
+++ b/lib/src/main/java/org/asamk/signal/manager/helper/AttachmentHelper.java
@@ -168,7 +168,7 @@ public class AttachmentHelper {
         try {
             attachmentStore.storeAttachment(pointer, outputStream -> this.retrieveAttachment(pointer, outputStream));
         } catch (IOException e) {
-            logger.warn("Failed to download attachment ({}), ignoring: {}", pointer.getRemoteId(), e.getMessage());
+            logger.warn("Failed to download attachment ({}), ignoring", pointer.getRemoteId(), e);
         }
     }
 
diff --git a/lib/src/main/java/org/asamk/signal/manager/storage/AttachmentStore.java b/lib/src/main/java/org/asamk/signal/manager/storage/AttachmentStore.java
index 00a284dd..44ea22d4 100644
--- a/lib/src/main/java/org/asamk/signal/manager/storage/AttachmentStore.java
+++ b/lib/src/main/java/org/asamk/signal/manager/storage/AttachmentStore.java
@@ -8,9 +8,11 @@ import org.whispersystems.signalservice.api.messages.SignalServiceAttachmentRemo
 import org.whispersystems.signalservice.api.util.StreamDetails;
 
 import java.io.File;
-import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.file.AtomicMoveNotSupportedException;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
 import java.util.Optional;
 
 public class AttachmentStore {
@@ -51,8 +53,23 @@ public class AttachmentStore {
 
     private void storeAttachment(final File attachmentFile, final AttachmentStorer storer) throws IOException {
         createAttachmentsDir();
-        try (OutputStream output = new FileOutputStream(attachmentFile)) {
-            storer.store(output);
+        final var temporaryFile = Files.createTempFile(attachmentsPath.toPath(),
+                attachmentFile.getName() + ".",
+                ".tmp");
+        try {
+            try (OutputStream output = Files.newOutputStream(temporaryFile)) {
+                storer.store(output);
+            }
+            try {
+                Files.move(temporaryFile,
+                        attachmentFile.toPath(),
+                        StandardCopyOption.ATOMIC_MOVE,
+                        StandardCopyOption.REPLACE_EXISTING);
+            } catch (AtomicMoveNotSupportedException e) {
+                Files.move(temporaryFile, attachmentFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
+            }
+        } finally {
+            Files.deleteIfExists(temporaryFile);
         }
     }