v3: code quality pass, various bug fixes

api/services/dump-service.ts

@@ -374,22 +374,32 @@ export async function replaceFileDump(
   }
 
   const data = new Uint8Array(await file.arrayBuffer());
-  await Deno.writeFile(`${DUMPS_DIR}/${dumpId}`, data);
+  const filePath = `${DUMPS_DIR}/${dumpId}`;
+  // Read old file contents so we can restore on DB failure
+  const oldData = await Deno.readFile(filePath).catch(() => null);
+  await Deno.writeFile(filePath, data);
 
   const now = new Date();
   const newSlug = makeSlug(file.name, dumpId);
-  db.prepare(
-    `UPDATE dumps SET title = ?, slug = ?, file_name = ?, file_mime = ?, file_size = ?, comment = ?, updated_at = ? WHERE id = ?;`,
-  ).run(
-    file.name,
-    newSlug,
-    file.name,
-    file.type,
-    file.size,
-    comment ?? null,
-    now.toISOString(),
-    dumpId,
-  );
+  try {
+    db.prepare(
+      `UPDATE dumps SET title = ?, slug = ?, file_name = ?, file_mime = ?, file_size = ?, comment = ?, updated_at = ? WHERE id = ?;`,
+    ).run(
+      file.name,
+      newSlug,
+      file.name,
+      file.type,
+      file.size,
+      comment ?? null,
+      now.toISOString(),
+      dumpId,
+    );
+  } catch (err) {
+    // Roll back the file to its previous contents on DB failure
+    if (oldData) await Deno.writeFile(filePath, oldData).catch(() => {});
+    else await Deno.remove(filePath).catch(() => {});
+    throw err;
+  }
 
   if (comment) notifyMentions(dump.userId, comment, "dump", dumpId, file.name);
   return {