Fix failure accounting, add comments

NBTUtil/ConsoleOptions.cs

@@ -56,6 +56,7 @@ namespace NBTUtil
                     if (!string.IsNullOrEmpty(v))
                         Values.Add(v);
                 }},
+                { "delete", "Delete the NBT tag if found", v => Command = ConsoleCommand.DeleteValue },
                 { "help", "Print this help message", v => Command = ConsoleCommand.Help },
                 { "<>", v => {
                     switch (_currentKey) {
@@ -65,7 +66,6 @@ namespace NBTUtil
                             break;
                     }
                 }},
-                { "delete", "Delete the NBT tag if found", v => Command = ConsoleCommand.DeleteValue },
             };
         }
 

NBTUtil/ConsoleRunner.cs

@@ -29,6 +29,8 @@ namespace NBTUtil
 
         public bool Run (string[] args)
         {
+            // Parse and validate command line arguments.
+
             _options.Parse(args);
 
             if (_options.Command == ConsoleCommand.Help)
@@ -48,6 +50,9 @@ namespace NBTUtil
 
             var nodesToProcess = new List<DataNode>();
 
+            // Iterate over all nodes matching the provided Path and create a list of the ones that can be processed
+            // using the provided ConsoleCommand.
+
             foreach (var node in new NbtPathEnumerator(_options.Path))
             {
                 if (op.CanProcess(node))
@@ -61,18 +66,29 @@ namespace NBTUtil
                 }
             }
 
+            // Iterate over all the processable nodes and process them.
+            // Doing this separately from the CanProcess loop allows Process to make significant changes to the NBT
+            // tree like node deletion.
+
             foreach (var targetNode in nodesToProcess) {
+                // Since Process may render targetNode inoperable, save targetNode.Root beforehand.
                 var root = targetNode.Root;
 
-                if (!op.Process(targetNode, _options)) {
+                if (op.Process(targetNode, _options))
+                {
+                    // Now that processing has succeeded, save the changes.
+                    root.Save();
+                    Console.WriteLine(targetNode.NodePath + ": OK");
+                    successCount++;
+                }
+                else
+                {
+                    // Since processing failed, discard any changes that may have been made. This prevents other
+                    // iterations of this loop from saving them.
+                    targetNode.RefreshNode();
                     Console.WriteLine(targetNode.NodePath + ": ERROR (apply)");
                     failCount++;
                 }
-
-                root.Save();
-
-                Console.WriteLine(targetNode.NodePath + ": OK");
-                successCount++;
             }
 
             Console.WriteLine("Operation complete.  Nodes succeeded: {0}  Nodes failed: {1}", successCount, failCount);