Real fix for the problem with duplicate fileset timestamp on really short backups

Duplicati/Library/Main/Operation/BackupHandler.cs

@@ -700,7 +700,14 @@ namespace Duplicati.Library.Main.Operation
 
                             m_database.BuildLookupTable(m_options);
                             m_transaction = m_database.BeginTransaction();
+
+                            var repcnt = 0;
+                            while(repcnt < 100 && m_database.GetRemoteVolumeID(filesetvolume.RemoteFilename) >= 0)
+                                filesetvolume.ResetRemoteFilename(m_options, m_database.OperationTimestamp.AddSeconds(repcnt));
         		            
+                            if (m_database.GetRemoteVolumeID(filesetvolume.RemoteFilename) >= 0)
+                                throw new Exception("Unable to generate a unique fileset name");
+
                             m_result.OperationProgressUpdater.UpdatePhase(OperationPhase.Backup_ProcessingFiles);
                             var filesetvolumeid = m_database.RegisterRemoteVolume(filesetvolume.RemoteFilename, RemoteVolumeType.Files, RemoteVolumeState.Temporary, m_transaction);
                             m_database.CreateFileset(filesetvolumeid, VolumeBase.ParseFilename(filesetvolume.RemoteFilename).Time, m_transaction);

Duplicati/Library/Main/Volumes/VolumeWriterBase.cs

@@ -40,12 +40,17 @@ namespace Duplicati.Library.Main.Volumes
         	
         }
 
+        public void ResetRemoteFilename(Options options, DateTime timestamp)
+        {
+            m_volumename = GenerateFilename(this.FileType, options.Prefix, GenerateGuid(options), timestamp, options.CompressionModule, options.NoEncryption ? null : options.EncryptionModule);
+        }
+
         public VolumeWriterBase(Options options, DateTime timestamp)
             : base(options)
         {
             m_localfile = new Library.Utility.TempFile();
 
-			m_volumename = GenerateFilename(this.FileType, options.Prefix, GenerateGuid(options), timestamp, options.CompressionModule, options.NoEncryption ? null : options.EncryptionModule);
+            ResetRemoteFilename(options, timestamp);
             m_compression = DynamicLoader.CompressionLoader.GetModule(options.CompressionModule, m_localfile, options.RawOptions);
             
             if(m_compression == null)

Duplicati/UnitTest/Issue1410.cs

@@ -51,8 +51,6 @@ namespace Duplicati.UnitTest
                 Console.WriteLine(string.Join(Environment.NewLine, r.Files.Select(x => x.Path)));
             }
 
-            System.Threading.Thread.Sleep(2000);
-
             new Random().NextBytes(data);
             File.WriteAllBytes(Path.Combine(DATAFOLDER, "b"), data);
             using(var c = new Library.Main.Controller("file://" + TARGETFOLDER, TestOptions, null))