Fix #8262 ToPageAsync() attempting to select invalid properties

src/GreenDonut/src/GreenDonut.Data.EntityFramework/Expressions/ExpressionHelpers.cs

@@ -343,7 +343,7 @@ private static bool IsNullable(LambdaExpression expression)
         }
 
         // For computed key expressions (method calls, concatenation, etc.) we cannot inspect
-        // NRT annotations at runtime. Treat as non-nullable — the safe default that avoids
+        // NRT annotations at runtime. Treat as non-nullable, the safe default that avoids
         // injecting spurious null-handling into the generated WHERE clause.
         return false;
     }
@@ -769,7 +769,6 @@ private sealed class OrderByRemovalRewriter : ExpressionVisitor
     {
         private readonly List<LambdaExpression> _orderExpressions = [];
         private readonly List<string> _orderMethods = [];
-        private bool _insideSelectProjection;
 
         public (Expression, List<LambdaExpression>, List<string>) Rewrite(Expression expression)
         {
@@ -783,27 +782,11 @@ private sealed class OrderByRemovalRewriter : ExpressionVisitor
 
         protected override Expression VisitMethodCall(MethodCallExpression node)
         {
-            // we are not interested in nested order by calls
-            if (node.Method.DeclaringType == typeof(Queryable) && node.Method.Name == nameof(Queryable.Select))
-            {
-                // We first visit our parent. When we visit an expression
-                // like "OrderBy().Select()", we want to visit the OrderBy first.
-                var source = Visit(node.Arguments[0]);
-
-                var previousState = _insideSelectProjection;
-                _insideSelectProjection = true;
-                var projection = Visit(node.Arguments[1]);
-                _insideSelectProjection = previousState;
-
-                return node.Update(null, [source, projection]);
-            }
-
             if (node.Method.DeclaringType == typeof(Queryable)
                 && (node.Method.Name == nameof(Queryable.OrderBy)
                     || node.Method.Name == nameof(Queryable.OrderByDescending)
                     || node.Method.Name == nameof(Queryable.ThenBy)
-                    || node.Method.Name == nameof(Queryable.ThenByDescending))
-                && !_insideSelectProjection)
+                    || node.Method.Name == nameof(Queryable.ThenByDescending)))
             {
                 var lambda = (LambdaExpression)StripQuotes(node.Arguments[1]);
                 _orderExpressions.Add(lambda);
@@ -814,6 +797,8 @@ protected override Expression VisitMethodCall(MethodCallExpression node)
             return base.VisitMethodCall(node);
         }
 
+        protected override Expression VisitLambda<T>(Expression<T> node) => node;
+
         private static Expression StripQuotes(Expression e)
         {
             while (e.NodeType == ExpressionType.Quote)

src/GreenDonut/src/GreenDonut.Data.EntityFramework/Expressions/ExtractOrderPropertiesVisitor.cs

@@ -8,8 +8,6 @@ internal sealed class ExtractOrderPropertiesVisitor : ExpressionVisitor
     private const string ThenByMethod = "ThenBy";
     private const string OrderByDescendingMethod = "OrderByDescending";
     private const string ThenByDescendingMethod = "ThenByDescending";
-    private bool _isOrderScope;
-
     public List<MemberExpression> OrderProperties { get; } = [];
 
     protected override Expression VisitMethodCall(MethodCallExpression node)
@@ -19,26 +17,29 @@ protected override Expression VisitMethodCall(MethodCallExpression node)
             || node.Method.Name == OrderByDescendingMethod
             || node.Method.Name == ThenByDescendingMethod)
         {
-            _isOrderScope = true;
-
             var lambda = StripQuotes(node.Arguments[1]);
-            Visit(lambda.Body);
-
-            _isOrderScope = false;
+            new OrderPropertyVisitor(lambda.Parameters[0], OrderProperties).Visit(lambda.Body);
         }
 
         return base.VisitMethodCall(node);
     }
 
-    protected override Expression VisitMember(MemberExpression node)
+    protected override Expression VisitLambda<T>(Expression<T> node) => node;
+
+    private sealed class OrderPropertyVisitor(
+        ParameterExpression orderKeyParameter,
+        List<MemberExpression> orderProperties)
+        : ExpressionVisitor
     {
-        if (_isOrderScope)
+        protected override Expression VisitMember(MemberExpression node)
         {
-            // we only collect members that are within an order method.
-            OrderProperties.Add(node);
-        }
+            if (node.Expression == orderKeyParameter)
+            {
+                orderProperties.Add(node);
+            }
 
-        return base.VisitMember(node);
+            return base.VisitMember(node);
+        }
     }
 
     private static LambdaExpression StripQuotes(Expression expression)

src/GreenDonut/src/GreenDonut.Data.EntityFramework/Expressions/ReverseOrderExpressionRewriter.cs

@@ -52,6 +52,8 @@ protected override Expression VisitMethodCall(MethodCallExpression node)
         return base.VisitMethodCall(node);
     }
 
+    protected override Expression VisitLambda<T>(Expression<T> node) => node;
+
     public static IQueryable<T> Rewrite<T>(IQueryable<T> query)
     {
         var reversedExpression = new ReverseOrderExpressionRewriter().Visit(query.Expression);

src/GreenDonut/src/GreenDonut.Data/Cursors/CursorKeyParser.cs

@@ -15,6 +15,8 @@ public sealed class CursorKeyParser : ExpressionVisitor
     protected override Expression VisitExtension(Expression node)
         => node.CanReduce ? base.VisitExtension(node) : node;
 
+    protected override Expression VisitLambda<T>(Expression<T> node) => node;
+
     protected override Expression VisitMethodCall(MethodCallExpression node)
     {
         if (IsOrderBy(node))

src/GreenDonut/test/GreenDonut.Data.EntityFramework.Tests/PagingHelperIntegrationTests.cs

@@ -276,6 +276,51 @@ public async Task BatchPaging_First_5()
         snapshot.MatchMarkdownSnapshot();
     }
 
+    [Fact]
+    public async Task ToBatchPageAsync_Should_PreserveNestedOrdering_When_PredicateContainsOrderBy()
+    {
+        // Arrange
+        var snapshot = Snapshot.Create(postFix: TestEnvironment.TargetFramework);
+
+        var connectionString = CreateConnectionString();
+        await SeedAsync(connectionString);
+        using var capture = new CapturePagingQueryInterceptor();
+
+        // Act
+        await using var context = new CatalogContext(connectionString);
+
+        var results = await context.Products
+            .Where(t =>
+                (t.BrandId == 1 || t.BrandId == 2 || t.BrandId == 3)
+                && t.Brand!.Products
+                    .AsQueryable()
+                    .OrderByDescending(p => p.Name)
+                    .First()
+                    .Id > 0)
+            .OrderBy(p => p.Name)
+            .ThenBy(p => p.Id)
+            .ToBatchPageAsync(
+                k => k.BrandId,
+                new PagingArguments { First = 2 },
+                Xunit.TestContext.Current.CancellationToken);
+
+        // Assert
+        foreach (var page in results)
+        {
+            snapshot.Add(
+                new
+                {
+                    First = page.Value.CreateStartCursor(),
+                    Last = page.Value.CreateEndCursor(),
+                    Items = page.Value.Items.Select(t => new { t.Id, t.Name })
+                },
+                name: page.Key.ToString());
+        }
+
+        snapshot.AddQueries(capture.Queries);
+        snapshot.MatchMarkdownSnapshot();
+    }
+
     [Fact]
     public async Task BatchPaging_Last_5()
     {