Fix compile warnings, other clean-up

Core/Extensions/EnumerableExtensions.cs

@@ -87,6 +87,19 @@ public static IEnumerable<V> ZipMany<T, U, V>(this IEnumerable<T> seq1, IEnumera
         public static IEnumerable<T> DistinctBy<T, U>(this IEnumerable<T> seq, Func<T, U> func)
             => seq.GroupBy(func).Select(grp => grp.First());
 
+        /// <summary>
+        /// Generate a sequence from a linked list
+        /// </summary>
+        /// <param name="start">The first node</param>
+        /// <param name="getNext">Function to go from one node to the next</param>
+        /// <returns>All the nodes in the list as a sequence</returns>
+        public static IEnumerable<T> TraverseNodes<T>(this T start, Func<T, T> getNext)
+        {
+            for (T t = start; t != null; t = getNext(t))
+            {
+                yield return t;
+            }
+        }
     }
 
     /// <summary>

GUI/Controls/EditModSearch.cs

@@ -143,7 +143,6 @@ private bool SkipDelayIf(object sender, EventArgs e)
                         default:
                             return false;
                     }
-                    break;
             }
             // Always refresh immediately on clear
             return string.IsNullOrEmpty(FilterCombinedTextBox.Text)

GUI/Controls/ManageMods.cs

@@ -502,7 +502,7 @@ private void MarkAllUpdatesToolButton_Click(object sender, EventArgs e)
 
         private void ApplyToolButton_Click(object sender, EventArgs e)
         {
-            Main.Instance.tabController.ShowTab("ChangesetTabPage", 1);
+            StartChangeSet?.Invoke(currentChangeSet);
         }
 
         public void MarkModForUpdate(string identifier, bool value)
@@ -759,7 +759,7 @@ private void ModGrid_CellMouseDoubleClick(object sender, DataGridViewCellMouseEv
             ModGrid.CommitEdit(DataGridViewDataErrorContexts.Commit);
         }
 
-        private async void ModGrid_CellValueChanged(object sender, DataGridViewCellEventArgs e)
+        private void ModGrid_CellValueChanged(object sender, DataGridViewCellEventArgs e)
         {
             int row_index    = e.RowIndex;
             int column_index = e.ColumnIndex;
@@ -804,10 +804,9 @@ private async void ModGrid_CellValueChanged(object sender, DataGridViewCellEvent
                             gui_mod.SetReplaceChecked(row, ReplaceCol);
                             break;
                     }
-                    await UpdateChangeSetAndConflicts(
+                    UpdateChangeSetAndConflicts(
                         Main.Instance.CurrentInstance,
-                        RegistryManager.Instance(Main.Instance.CurrentInstance).registry
-                    );
+                        RegistryManager.Instance(Main.Instance.CurrentInstance).registry);
                 }
             }
         }
@@ -1227,8 +1226,7 @@ private void _UpdateModsList(Dictionary<string, bool> old_modules = null)
             // Update our mod listing
             mainModList.ConstructModList(gui_mods, Main.Instance.CurrentInstance.Name, Main.Instance.CurrentInstance.game, ChangeSet);
 
-            // C# 7.0: Executes the task and discards it
-            _ = UpdateChangeSetAndConflicts(Main.Instance.CurrentInstance, registry);
+            UpdateChangeSetAndConflicts(Main.Instance.CurrentInstance, registry);
 
             Main.Instance.Wait.AddLogMessage(Properties.Resources.MainModListUpdatingFilters);
 
@@ -1651,7 +1649,7 @@ public void InstanceUpdated(GameInstance inst)
             Conflicts = null;
         }
 
-        public async Task UpdateChangeSetAndConflicts(GameInstance inst, IRegistryQuerier registry)
+        public void UpdateChangeSetAndConflicts(GameInstance inst, IRegistryQuerier registry)
         {
             if (freezeChangeSet)
             {
@@ -1662,7 +1660,6 @@ public async Task UpdateChangeSetAndConflicts(GameInstance inst, IRegistryQuerie
             List<ModChange> full_change_set = null;
             Dictionary<GUIMod, string> new_conflicts = null;
 
-            bool too_many_provides_thrown = false;
             var user_change_set = mainModList.ComputeUserChangeSet(registry, inst.VersionCriteria());
             try
             {

GUI/Controls/ModInfo.cs

@@ -44,7 +44,7 @@ public GUIMod SelectedModule
 
         public void RefreshModContentsTree()
         {
-            Contents.Refresh();
+            Contents.RefreshModContentsTree();
         }
 
         public event Action<GUIMod>            OnDownloadClick;

GUI/Controls/ModInfoTabs/Contents.cs

@@ -29,7 +29,7 @@ public GUIMod SelectedModule
             get => selectedModule;
         }
 
-        public void Refresh()
+        public void RefreshModContentsTree()
         {
             if (currentModContentsModule != null)
             {

GUI/Dialogs/PreferredHostsDialog.cs

@@ -66,7 +66,7 @@ private void PreferredHostsListBox_SelectedIndexChanged(object sender, EventArgs
         {
             var haveSelection      = PreferredHostsListBox.SelectedIndex > -1;
             MoveLeftButton.Enabled = haveSelection
-                                     && PreferredHostsListBox.SelectedItem != placeholder;
+                                     && (string)PreferredHostsListBox.SelectedItem != placeholder;
             MoveUpButton.Enabled   = PreferredHostsListBox.SelectedIndex > 0;
             MoveDownButton.Enabled = haveSelection
                                      && PreferredHostsListBox.SelectedIndex < PreferredHostsListBox.Items.Count - 1;
@@ -115,7 +115,7 @@ private void MoveLeftButton_Click(object sender, EventArgs e)
             if (PreferredHostsListBox.SelectedIndex > -1)
             {
                 var fromWhere = PreferredHostsListBox.SelectedIndex;
-                var selected = PreferredHostsListBox.SelectedItem;
+                var selected  = (string)PreferredHostsListBox.SelectedItem;
                 if (selected != placeholder)
                 {
                     PreferredHostsListBox.Items.Remove(selected);

GUI/Main/Main.cs

@@ -28,17 +28,16 @@ public partial class Main : Form, IMessageFilter
 
         // Stuff we set in the constructor and never change
         public readonly GUIUser currentUser;
-        [Obsolete("Main.tabController should be private. Find a better way to access this object.")]
-        public readonly TabController tabController;
-        private readonly GameInstanceManager manager;
-        public GameInstanceManager Manager => manager;
+        public readonly GameInstanceManager Manager;
         public GameInstance CurrentInstance => Manager.CurrentInstance;
-        private string focusIdent;
 
         // Stuff we set when the game instance changes
         public GUIConfiguration configuration;
         public PluginController pluginController;
 
+        private readonly TabController tabController;
+        private string focusIdent;
+
         private bool needRegistrySave = false;
 
         [Obsolete("Main.Instance is a global singleton. Find a better way to access this object.")]
@@ -128,11 +127,11 @@ public Main(string[] cmdlineArgs, GameInstanceManager mgr)
             {
                 // With a working GUI, assign a GUIUser to the GameInstanceManager to replace the ConsoleUser
                 mgr.User = currentUser;
-                manager = mgr;
+                Manager = mgr;
             }
             else
             {
-                manager = new GameInstanceManager(currentUser);
+                Manager = new GameInstanceManager(currentUser);
             }
 
             tabController = new TabController(MainTabControl);
@@ -148,13 +147,13 @@ protected override void OnLoad(EventArgs e)
             if (CurrentInstance == null)
             {
                 // Maybe we can find an instance automatically (e.g., portable, only, default)
-                manager.GetPreferredInstance();
+                Manager.GetPreferredInstance();
             }
 
             // We need a config object to get the window geometry, but we don't need the registry lock yet
             configuration = GUIConfigForInstance(
                 // Find the most recently used instance if no default instance
-                CurrentInstance ?? InstanceWithNewestGUIConfig(manager.Instances.Values));
+                CurrentInstance ?? InstanceWithNewestGUIConfig(Manager.Instances.Values));
 
             // This must happen before Shown, and it depends on the configuration
             SetStartPosition();
@@ -255,8 +254,8 @@ protected override void OnShown(EventArgs e)
                                 else
                                 {
                                     // Couldn't get the lock, there is no current instance
-                                    manager.CurrentInstance = null;
-                                    if (manager.Instances.Values.All(inst => !inst.Valid || inst.IsMaybeLocked))
+                                    Manager.CurrentInstance = null;
+                                    if (Manager.Instances.Values.All(inst => !inst.Valid || inst.IsMaybeLocked))
                                     {
                                         // Everything's invalid or locked, give up
                                         evt.Result = false;
@@ -336,7 +335,7 @@ private void manageGameInstancesMenuItem_Click(object sender, EventArgs e)
                         else
                         {
                             // Couldn't get the lock, revert to previous instance
-                            manager.CurrentInstance = old_instance;
+                            Manager.CurrentInstance = old_instance;
                             CurrentInstanceUpdated(false);
                             done = true;
                         }
@@ -443,7 +442,7 @@ protected override void OnFormClosed(FormClosedEventArgs e)
             }
 
             // Stop all running play time timers
-            foreach (var inst in manager.Instances.Values)
+            foreach (var inst in Manager.Instances.Values)
             {
                 if (inst.Valid)
                 {
@@ -694,7 +693,7 @@ private void InstallFromCkanFiles(string[] files)
         private void CompatibleGameVersionsToolStripMenuItem_Click(object sender, EventArgs e)
         {
             CompatibleGameVersionsDialog dialog = new CompatibleGameVersionsDialog(
-                Instance.manager.CurrentInstance,
+                Instance.Manager.CurrentInstance,
                 !actuallyVisible
             );
             if (dialog.ShowDialog(this) != DialogResult.Cancel)
@@ -839,7 +838,7 @@ private void Main_Resize(object sender, EventArgs e)
 
         private void openGameDirectoryToolStripMenuItem_Click(object sender, EventArgs e)
         {
-            Utilities.ProcessStartURL(manager.CurrentInstance.GameDir());
+            Utilities.ProcessStartURL(Manager.CurrentInstance.GameDir());
         }
 
         private void openGameToolStripMenuItem_Click(object sender, EventArgs e)

GUI/Main/MainHistory.cs

@@ -14,7 +14,7 @@ public partial class Main
     {
         private void installationHistoryStripMenuItem_Click(object sender, EventArgs e)
         {
-            InstallationHistory.LoadHistory(manager.CurrentInstance, configuration);
+            InstallationHistory.LoadHistory(Manager.CurrentInstance, configuration);
             tabController.ShowTab("InstallationHistoryTabPage", 2);
             DisableMainWindow();
         }

GUI/Main/MainInstall.cs

@@ -60,7 +60,7 @@ private void InstallMods(object sender, DoWorkEventArgs e)
             bool canceled = false;
             var opts = (KeyValuePair<ModChanges, RelationshipResolverOptions>) e.Argument;
 
-            RegistryManager registry_manager = RegistryManager.Instance(manager.CurrentInstance);
+            RegistryManager registry_manager = RegistryManager.Instance(Manager.CurrentInstance);
             Registry registry = registry_manager.registry;
             ModuleInstaller installer = new ModuleInstaller(CurrentInstance, Manager.Cache, currentUser);
             // Avoid accumulating multiple event handlers
@@ -392,11 +392,23 @@ private void PostInstallMods(object sender, RunWorkerCompletedEventArgs e)
                         break;
 
                     case TransactionalKraken exc:
+                        // Thrown when the Registry tries to enlist with multiple different transactions
                         // Want to see the stack trace for this one
                         currentUser.RaiseMessage(exc.ToString());
                         currentUser.RaiseError(exc.ToString());
                         break;
 
+                    case TransactionException texc:
+                        // "Failed to roll back" is useless by itself,
+                        // so show all inner exceptions too
+                        foreach (var exc in texc.TraverseNodes<Exception>(ex => ex.InnerException)
+                                                .Reverse())
+                        {
+                            log.Error(exc.Message, exc);
+                            currentUser.RaiseMessage(exc.Message);
+                        }
+                        break;
+
                     default:
                         currentUser.RaiseMessage(e.Error.Message);
                         break;

GUI/Main/MainRepo.cs

@@ -4,13 +4,15 @@
 using System.Timers;
 using System.Linq;
 using System.Windows.Forms;
+using System.Transactions;
 using Timer = System.Timers.Timer;
 
 using Newtonsoft.Json;
 using Autofac;
 
 using CKAN.Versioning;
 using CKAN.Configuration;
+using CKAN.Extensions;
 
 // Don't warn if we use our own obsolete properties
 #pragma warning disable 0618
@@ -158,9 +160,23 @@ private void PostUpdateRepo(object sender, RunWorkerCompletedEventArgs e)
                         EnableMainWindow();
                         break;
 
-                    case Exception exc:
+                    case TransactionException texc:
+                        // "Failed to roll back" is useless by itself,
+                        // so show all inner exceptions too
+                        foreach (var exc in texc.TraverseNodes<Exception>(ex => ex.InnerException)
+                                                .Reverse())
+                        {
+                            log.Error(exc.Message, exc);
+                            currentUser.RaiseMessage(exc.Message);
+                        }
                         AddStatusMessage(Properties.Resources.MainRepoFailed);
+                        Wait.Finish();
+                        EnableMainWindow();
+                        break;
+
+                    case Exception exc:
                         currentUser.RaiseMessage(exc.Message);
+                        AddStatusMessage(Properties.Resources.MainRepoFailed);
                         Wait.Finish();
                         EnableMainWindow();
                         break;

GUI/Main/MainTime.cs

@@ -9,7 +9,7 @@ public partial class Main
     {
         private void viewPlayTimeStripMenuItem_Click(object sender, EventArgs e)
         {
-            PlayTime.loadAllPlayTime(manager);
+            PlayTime.loadAllPlayTime(Manager);
             tabController.ShowTab("PlayTimeTabPage", 2);
             DisableMainWindow();
         }

GUI/Main/MainUnmanaged.cs

@@ -9,7 +9,7 @@ public partial class Main
     {
         private void viewUnmanagedFilesStripMenuItem_Click(object sender, EventArgs e)
         {
-            UnmanagedFiles.LoadFiles(manager.CurrentInstance, currentUser);
+            UnmanagedFiles.LoadFiles(Manager.CurrentInstance, currentUser);
             tabController.ShowTab("UnmanagedFilesTabPage", 2);
             DisableMainWindow();
         }

GUI/Model/GUIMod.cs

@@ -41,11 +41,9 @@ public  CkanModule      SelectedMod
                     }
                     Main.Instance.ManageMods.MarkModForInstall(Identifier, selectedMod == null);
 
-                    // C# 7.0: Executes the task and discards it
-                    _ = Main.Instance.ManageMods.UpdateChangeSetAndConflicts(
+                    Main.Instance.ManageMods.UpdateChangeSetAndConflicts(
                         Main.Instance.Manager.CurrentInstance,
-                        RegistryManager.Instance(Main.Instance.Manager.CurrentInstance).registry
-                    );
+                        RegistryManager.Instance(Main.Instance.Manager.CurrentInstance).registry);
 
                     OnPropertyChanged();
                 }