Bug fix, DeltaTree was not updating numItems after erase / insert operations which only change the deleted flag of an existing equivalent entry.

fdbserver/DeltaTree.h

@@ -370,6 +370,7 @@ public:
 						auto &d = n->raw->delta();
 						if(d.getDeleted()) {
 							d.setDeleted(false);
+							++tree->numItems;
 							return true;
 						}
 						else {
@@ -504,6 +505,7 @@ public:
 
 		void erase() {
 			node->setDeleted(true);
+			--mirror->tree->numItems;
 			moveNext();
 		}
 

fdbserver/VersionedBTree.actor.cpp

@@ -5699,21 +5699,27 @@ TEST_CASE("!/redwood/correctness/unit/deltaTree/RedwoodRecordRef") {
 
 	// Test delete/insert behavior for each item, making no net changes
 	printf("Testing seek/delete/insert for existing keys with random values\n");
+	ASSERT(tree->numItems == items.size());
 	for(auto rec : items) {
 		// Insert existing should fail
 		ASSERT(!r.insert(rec));
+		ASSERT(tree->numItems == items.size());
 
 		// Erase existing should succeed
 		ASSERT(r.erase(rec));
+		ASSERT(tree->numItems == items.size() - 1);
 
 		// Erase deleted should fail
 		ASSERT(!r.erase(rec));
+		ASSERT(tree->numItems == items.size() - 1);
 
 		// Insert deleted should succeed
 		ASSERT(r.insert(rec));
+		ASSERT(tree->numItems == items.size());
 
 		// Insert existing should fail
 		ASSERT(!r.insert(rec));
+		ASSERT(tree->numItems == items.size());
 	}
 
 	DeltaTree<RedwoodRecordRef>::Cursor fwd = r.getCursor();