RavenDB-22964 Fix MoveNext for BackwardIterator

src/Voron/Data/Lookups/Lookup.Iterator.cs

@@ -374,6 +374,14 @@ public bool MoveNext(out long value)
                     return false;
                 }
                 ref var state = ref _cursor._stk[_cursor._pos];
+
+                // LastMatch equal to -1 is an indicator that we didn't find seeked key (or its successor doesn't exist) 
+                if (state.LastMatch == -1)
+                {
+                    value = default;
+                    return false;
+                }
+
                 while (true)
                 {
                     Debug.Assert(state.Header->PageFlags.HasFlag(LookupPageFlags.Leaf));
@@ -407,6 +415,16 @@ public bool MoveNext<T>(out T key, out long value, out bool hasPreviousValue)
                     return false;
                 }
                 ref var state = ref _cursor._stk[_cursor._pos];
+
+                // LastMatch equal to -1 is an indicator that we didn't find seeked key (or its successor doesn't exist) 
+                if (state.LastMatch == -1)
+                {
+                    value = default;
+                    key = default;
+                    hasPreviousValue = false;
+                    return false;
+                }
+
                 while (true)
                 {
                     Debug.Assert(state.Header->PageFlags.HasFlag(LookupPageFlags.Leaf));

test/SlowTests/Issues/RavenDB-22964.cs

@@ -0,0 +1,115 @@
+using System.Linq;
+using FastTests;
+using Tests.Infrastructure;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace SlowTests.Issues;
+
+public class RavenDB_22964 : RavenTestBase
+{
+    public RavenDB_22964(ITestOutputHelper output) : base(output)
+    {
+    }
+
+    [RavenTheory(RavenTestCategory.Corax | RavenTestCategory.Querying)]
+    [RavenData(SearchEngineMode = RavenSearchEngineMode.Corax, DatabaseMode = RavenDatabaseMode.All)]
+    public void TestOrderByUsingBackwardIterator(Options options)
+    {
+        using (var store = GetDocumentStore(options))
+        {
+            using (var session = store.OpenSession())
+            {
+                var t1 = new TestObject() { Value = 1 };
+                var t2 = new TestObject() { Value = 3 };
+                var t3 = new TestObject() { Value = 4 };
+                var t4 = new TestObject() { Value = 5 };
+
+                session.Store(t1);
+                session.Store(t2);
+                session.Store(t3);
+                session.Store(t4);
+                session.SaveChanges();
+
+                long min = 2;
+                long max = 4;
+
+                var r1 = session.Query<TestObject>()
+                    .Where(x => x.Value > min && x.Value < max)
+                    .OrderByDescending(x => x.Value)
+                    .ToList();
+
+                Assert.Equal(1, r1.Count);
+                Assert.Equal(3, r1[0].Value);
+
+                var r2 = session.Query<TestObject>()
+                    .Where(x => x.Value > min && x.Value <= max)
+                    .OrderByDescending(x => x.Value)
+                    .ToList();
+
+                Assert.Equal(2, r2.Count);
+                Assert.Equal(4, r2[0].Value);
+                Assert.Equal(3, r2[1].Value);
+
+                var r3 = session.Query<TestObject>()
+                    .Where(x => x.Value >= min && x.Value <= max)
+                    .OrderByDescending(x => x.Value)
+                    .ToList();
+
+                Assert.Equal(2, r3.Count);
+                Assert.Equal(4, r3[0].Value);
+                Assert.Equal(3, r3[1].Value);
+
+                min = 0;
+
+                var r4 = session.Query<TestObject>()
+                    .Where(x => x.Value > min && x.Value < max)
+                    .OrderByDescending(x => x.Value)
+                    .ToList();
+
+                Assert.Equal(2, r4.Count);
+                Assert.Equal(3, r4[0].Value);
+                Assert.Equal(1, r4[1].Value);
+
+                max = 7;
+
+                var r5 = session.Query<TestObject>()
+                    .Where(x => x.Value > min && x.Value < max)
+                    .OrderByDescending(x => x.Value)
+                    .ToList();
+
+                Assert.Equal(4, r5.Count);
+                Assert.Equal(5, r5[0].Value);
+                Assert.Equal(4, r5[1].Value);
+                Assert.Equal(3, r5[2].Value);
+                Assert.Equal(1, r5[3].Value);
+
+                min = 10;
+                max = 15;
+
+                var r6 = session.Query<TestObject>()
+                    .Where(x => x.Value > min && x.Value < max)
+                    .OrderByDescending(x => x.Value)
+                    .ToList();
+
+                Assert.Equal(0, r6.Count);
+
+                min = -5;
+                max = -2;
+
+                var r7 = session.Query<TestObject>()
+                    .Where(x => x.Value > min && x.Value < max)
+                    .OrderByDescending(x => x.Value)
+                    .ToList();
+
+                Assert.Equal(0, r7.Count);
+            }
+        }
+    }
+
+    public class TestObject
+    {
+        public string Id { get; set; }
+        public required long Value { get; set; }
+    }
+}