#384 Initial Changes for confirmation

src/Paprika/Store/DataPage.cs

@@ -74,6 +74,11 @@ public Page DeleteByPrefix(in NibblePath prefix, IBatchContext batch)
                     buckets[prefix.Nibble0] = batch.GetAddress(child);
                 }
             }
+            else
+            {
+                batch.RegisterForFutureReuse(page);
+                return batch.NullPage;
+            }
         }
         else
         {

src/Paprika/Store/IBatchContext.cs

@@ -72,6 +72,8 @@ Page EnsureWritableCopy(ref DbAddress addr)
     Page TryGetPageAlloc(ref DbAddress addr, PageType pageType);
 
     BatchStats? Stats { get; }
+
+    public unsafe Page NullPage => new Page((byte*)0);
 }
 
 public class BatchStats : IBatchStats

src/Paprika/Store/LeafOverflowPage.cs

@@ -47,6 +47,11 @@ public Page DeleteByPrefix(in NibblePath prefix, IBatchContext batch)
             var writable = batch.GetWritableCopy(page);
             return new LeafOverflowPage(writable).DeleteByPrefix(prefix, batch);
         }
+        if (prefix.IsEmpty)
+        {
+            batch.RegisterForFutureReuse(page);
+            return batch.NullPage;
+        }
 
         Map.DeleteByPrefix(prefix);
 

src/Paprika/Store/PagedDb.cs

@@ -519,8 +519,8 @@ class Batch : BatchContextBase, IBatch
         private readonly RootPage _root;
         private readonly uint _reusePagesOlderThanBatchId;
         private bool _verify = false;
-        private bool _disposed;
-
+        private bool _disposed; 
+        
         private readonly Context _ctx;
 
         /// <summary>

src/Paprika/Store/StateRootPage.cs

@@ -75,6 +75,12 @@ public Page DeleteByPrefix(in NibblePath prefix, IBatchContext batch)
             return new StateRootPage(writable).DeleteByPrefix(prefix, batch);
         }
 
+        if (prefix.IsEmpty)
+        {
+            batch.RegisterForFutureReuse(page);
+            return batch.NullPage;
+        }
+
         Debug.Assert(prefix.Length > ConsumedNibbles, "Removing prefix at the root? Something went wrong.");
 
         var index = GetIndex(prefix);

src/Paprika/Store/StorageFanOut.cs

@@ -188,6 +188,12 @@ public Page DeleteByPrefix(in NibblePath prefix, IBatchContext batch)
                 var writable = batch.GetWritableCopy(page);
                 return new Level1Page(writable).DeleteByPrefix(prefix, batch);
             }
+            if (prefix.IsEmpty)
+            {
+                batch.RegisterForFutureReuse(page);
+                return batch.NullPage;
+            }
+
 
             var index = GetIndex(prefix, Type.Storage, out var sliced);