feat: AOT-safe property access: [KumikoGridItem] generator, column delegates, guarded reflection (#17)

.github/dependabot.yml

@@ -13,6 +13,9 @@ updates:
       # MauiVersion (Directory.Packages.props) is the deliberate minimum KumikoUI.Maui supports,
       # not a version to track: raising it forces every consumer onto that MAUI. Raise it by hand.
       - dependency-name: "Microsoft.Maui.Controls"
+      # The [KumikoGridItem] generator is built against the oldest Roslyn it supports; a newer
+      # Microsoft.CodeAnalysis.CSharp would stop older compilers from loading it. Raise it by hand.
+      - dependency-name: "Microsoft.CodeAnalysis.CSharp"
     groups:
       # One major version across the whole repository (see Directory.Packages.props).
       skiasharp:

.github/workflows/ci.yml

@@ -35,6 +35,7 @@ jobs:
         run: dotnet restore src/KumikoUI.Core/KumikoUI.Core.csproj
           && dotnet restore src/KumikoUI.SkiaSharp/KumikoUI.SkiaSharp.csproj
           && dotnet restore tests/KumikoUI.Core.Tests/KumikoUI.Core.Tests.csproj
+          && dotnet restore tests/KumikoUI.SourceGenerators.Tests/KumikoUI.SourceGenerators.Tests.csproj
 
       - name: Build — Core
         run: dotnet build src/KumikoUI.Core/KumikoUI.Core.csproj
@@ -55,6 +56,10 @@ jobs:
         run: dotnet test tests/KumikoUI.Core.Tests/KumikoUI.Core.Tests.csproj
           --no-restore -c Release --logger "trx" --results-directory TestResults
 
+      - name: Test — source generator
+        run: dotnet test tests/KumikoUI.SourceGenerators.Tests/KumikoUI.SourceGenerators.Tests.csproj
+          --no-restore -c Release --logger "trx" --results-directory TestResults
+
       - name: Upload test results
         if: always()
         uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2

.github/workflows/publish.yml

@@ -262,6 +262,9 @@ jobs:
           dotnet restore tests/KumikoUI.Core.Tests/KumikoUI.Core.Tests.csproj
           dotnet test tests/KumikoUI.Core.Tests/KumikoUI.Core.Tests.csproj \
             -c Release --logger "trx" --results-directory TestResults
+          dotnet restore tests/KumikoUI.SourceGenerators.Tests/KumikoUI.SourceGenerators.Tests.csproj
+          dotnet test tests/KumikoUI.SourceGenerators.Tests/KumikoUI.SourceGenerators.Tests.csproj \
+            -c Release --logger "trx" --results-directory TestResults
 
   test-uno:
     name: Run Uno tests

.gitignore

@@ -40,3 +40,6 @@ artifacts/
 Thumbs.db
 
 *.lscache
+
+# BenchmarkDotNet output (bench/)
+BenchmarkDotNet.Artifacts/

CHANGELOG.md

@@ -7,10 +7,19 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 ## [Unreleased]
 
 ### Added
+- Native AOT and trimming support (#17). Item properties are read and written, in order, through:
+  - `KumikoColumn.ValueAccessor` / `ValueSetter` delegates (and `EditorDisplaySelector` / `EditorValueSelector` for ComboBox items, `DrawnComboBox.DisplaySelector` / `ValueSelector`);
+  - accessors generated for types marked `[KumikoGridItem]` (`KumikoUI.Core.Data`), by a source generator now included in the KumikoUI.Core package;
+  - providers registered with `KumikoAccessorRegistry.Register` / `AddProvider` (`IKumikoAccessorProvider`, `KumikoPropertyAccessor`);
+  - reflection, as before.
+
+  Generated and delegate reads are 3–5× faster than the previous compiled expression trees, with 80% less allocation (`bench/KumikoUI.Benchmarks`). All four packages are marked `IsAotCompatible` and build with no trimming or AOT analyzer warnings; such warnings now fail the build.
 - **KumikoUI.Uno**: a new package hosting the grid on the Uno Platform (Windows App SDK, desktop on Windows/macOS/Linux, WebAssembly, Android, iOS) with the same engine, rendering and features as KumikoUI.Maui, plus `KumikoFonts` for registering custom fonts from app assets, and the `SampleApp.Uno` sample.
-- `DataGridStyle.PinBottomSummaryRows` (default `true`): `Position=Bottom` table summary rows are pinned to the bottom of the viewport as a fixed footer instead of scrolling after the last row. **Behaviour change** for existing users of bottom summaries; set it to `false` to restore the previous layout.
+- `KumikoStyle.PinBottomSummaryRows` (default `true`): `Position=Bottom` table summary rows are pinned to the bottom of the viewport as a fixed footer instead of scrolling after the last row. **Behaviour change** for existing users of bottom summaries; set it to `false` to restore the previous layout.
 
 ### Changed
+- The reflection fallback for item properties is off for `PublishAot=true` and `TrimMode=full` publishes (KumikoUI.Core build targets set the `KumikoUI.Core.IsReflectionPropertyAccessSupported` switch). A property with no generated accessor, delegate or provider then reads as null and is traced once. Override with the `KumikoReflectionPropertyAccess` MSBuild property. Partial trimming, the .NET MAUI default, is unaffected.
+- A nested property path with a `null` value part-way (`Address.City` when `Address` is null) now reads as an empty cell instead of throwing, and an edit to it is ignored.
 - **Breaking:** naming pass: every grid type now uses the `Kumiko` prefix (drawn components keep `Drawn`), and no public name collides with types of MAUI, CommunityToolkit.Maui, WinUI/Uno, the Windows Community Toolkit DataGrid, WPF, Windows Forms or Avalonia (#16). Namespaces are unchanged (`KumikoUI.*`); member names are unchanged (for example `KumikoColumn.SortDirection`, `KumikoDataGrid.GridSelectionMode` and `KumikoDataGrid.GridStyle` keep their names, only their types change). Update XAML and code as follows:
   - Host control: `DataGridView` → `KumikoDataGrid` in both `KumikoUI.Maui` and `KumikoUI.Uno`, including XAML (`<dg:DataGridView …>` → `<dg:KumikoDataGrid …>`, `<dg:DataGridView.Columns>` → `<dg:KumikoDataGrid.Columns>`, and the same for `TableSummaryRows` and `GroupSummaryRows`).
   - Models: `DataGridSource` → `KumikoSource`, `DataGridColumn` → `KumikoColumn` (including `<core:DataGridColumn …>` in XAML), `DataGridColumnType` → `KumikoColumnType`, `DataGridStyle` → `KumikoStyle`, `DataGridTheme` → `KumikoTheme`, `DataGridThemeMode` → `KumikoThemeMode`, `CellStyle` → `KumikoCellStyle`, `RowStyle` → `KumikoRowStyle`, `DataGridRenderer` → `KumikoRenderer`
@@ -36,6 +45,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 - KumikoUI.Uno is built with Uno.Sdk 6.7.30 (was 6.5.31).
 
 ### Fixed
+- ComboBox editors now apply the column's `EditorDisplayMemberPath` and `EditorValueMemberPath`; they were set after the items were built, so items showed `ToString()` and the current value was not selected.
 - An unknown font family now falls back to the default family in the requested weight and slant instead of producing a null typeface. Styled typefaces are resolved through `SKFontManager` with an explicit family, which SkiaSharp 4 needs to keep bold and italic.
 - Taps on the pinned summary footer no longer select or edit the data row behind it; unpinned bottom summary rows are also reported as `HitRegion.TableSummaryRow`.
 - Keyboard navigation keeps the current row fully visible between the header/frozen rows and the pinned footer, and accounts for the grouping panel and top summary rows (previously the scroll offset was counted twice).

CONTRIBUTING.md

@@ -46,8 +46,11 @@ Build what you are working on; the platform-agnostic projects need no workloads:
 dotnet build src/KumikoUI.Core
 dotnet build src/KumikoUI.SkiaSharp
 dotnet test tests/KumikoUI.Core.Tests
+dotnet test tests/KumikoUI.SourceGenerators.Tests
 ```
 
+The libraries are `IsAotCompatible`: a trimming or Native AOT analyzer warning (IL2xxx/IL3xxx) fails the build (`Directory.Build.targets`). Read item properties through `KumikoAccessorRegistry` rather than reflection (see "Native AOT & Trimming" in the README). Property-access benchmarks live in `bench/` (see `bench/README.md`).
+
 Check public type names after building (see [Public type names](#public-type-names)):
 
 ```bash

Directory.Build.targets

@@ -0,0 +1,15 @@
+<Project>
+  <!--
+    Libraries marked IsAotCompatible (KumikoUI.Core, .SkiaSharp, .Maui, .Uno) must stay free of trimming,
+    Native AOT and single-file analyzer warnings (#17).
+    - EnableTrimAnalyzer is forced on because the Apple workloads turn it off for library builds.
+    - Every IL2xxx/IL3xxx analyzer warning is an error, so a regression fails the build instead of
+      surfacing as a warning in apps that publish with trimming or Native AOT.
+  -->
+  <PropertyGroup Condition="'$(IsAotCompatible)' == 'true'">
+    <EnableTrimAnalyzer>true</EnableTrimAnalyzer>
+    <EnableAotAnalyzer>true</EnableAotAnalyzer>
+    <EnableSingleFileAnalyzer>true</EnableSingleFileAnalyzer>
+    <WarningsAsErrors>$(WarningsAsErrors);IL2001;IL2002;IL2003;IL2004;IL2005;IL2006;IL2007;IL2008;IL2009;IL2010;IL2011;IL2012;IL2013;IL2014;IL2015;IL2016;IL2017;IL2018;IL2019;IL2020;IL2021;IL2022;IL2023;IL2024;IL2025;IL2026;IL2027;IL2028;IL2029;IL2030;IL2031;IL2032;IL2033;IL2034;IL2035;IL2036;IL2037;IL2038;IL2039;IL2040;IL2041;IL2042;IL2043;IL2044;IL2045;IL2046;IL2047;IL2048;IL2049;IL2050;IL2051;IL2052;IL2053;IL2054;IL2055;IL2056;IL2057;IL2058;IL2059;IL2060;IL2061;IL2062;IL2063;IL2064;IL2065;IL2066;IL2067;IL2068;IL2069;IL2070;IL2071;IL2072;IL2073;IL2074;IL2075;IL2076;IL2077;IL2078;IL2079;IL2080;IL2081;IL2082;IL2083;IL2084;IL2085;IL2086;IL2087;IL2088;IL2089;IL2090;IL2091;IL2092;IL2093;IL2094;IL2095;IL2096;IL2097;IL2098;IL2099;IL2100;IL2101;IL2102;IL2103;IL2104;IL2105;IL2106;IL2107;IL2108;IL2109;IL2110;IL2111;IL2112;IL2113;IL2114;IL2115;IL2116;IL2117;IL2118;IL2119;IL2120;IL2121;IL2122;IL2123;IL3000;IL3001;IL3002;IL3003;IL3004;IL3005;IL3050;IL3051;IL3052;IL3053;IL3054;IL3055;IL3056;IL3057;IL3058</WarningsAsErrors>
+  </PropertyGroup>
+</Project>

Directory.Packages.props

@@ -82,6 +82,18 @@
     <PackageVersion Include="Avalonia.Controls.DataGrid" Version="$(AvaloniaDataGridVersion)" />
   </ItemGroup>
 
+  <!--
+    Roslyn for the [KumikoGridItem] source generator: the oldest compiler the generator supports. Apps on
+    .NET 10 compile with a newer Roslyn, which loads generators built against older ones.
+  -->
+  <ItemGroup Label="Source generator">
+    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="4.14.0" />
+  </ItemGroup>
+
+  <ItemGroup Label="Benchmarks">
+    <PackageVersion Include="BenchmarkDotNet" Version="0.15.8" />
+  </ItemGroup>
+
   <ItemGroup Label="Tests">
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.11.0" />
     <PackageVersion Include="xunit" Version="2.9.3" />

KumikoUI.sln

@@ -38,6 +38,10 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Build", "Build", "{DFDD4E5D
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "KumikoUI.Uno.Tests", "tests\KumikoUI.Uno.Tests\KumikoUI.Uno.Tests.csproj", "{57855B3A-D369-4D2D-8B43-FA09549FF955}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "KumikoUI.SourceGenerators", "src\KumikoUI.SourceGenerators\KumikoUI.SourceGenerators.csproj", "{EA495C23-8110-4B63-A97D-A8C68483F9B4}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "KumikoUI.SourceGenerators.Tests", "tests\KumikoUI.SourceGenerators.Tests\KumikoUI.SourceGenerators.Tests.csproj", "{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -144,6 +148,30 @@ Global
 		{57855B3A-D369-4D2D-8B43-FA09549FF955}.Release|x64.Build.0 = Release|Any CPU
 		{57855B3A-D369-4D2D-8B43-FA09549FF955}.Release|x86.ActiveCfg = Release|Any CPU
 		{57855B3A-D369-4D2D-8B43-FA09549FF955}.Release|x86.Build.0 = Release|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Debug|x64.Build.0 = Debug|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Debug|x86.Build.0 = Debug|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Release|Any CPU.Build.0 = Release|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Release|x64.ActiveCfg = Release|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Release|x64.Build.0 = Release|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Release|x86.ActiveCfg = Release|Any CPU
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4}.Release|x86.Build.0 = Release|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Debug|x64.Build.0 = Debug|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Debug|x86.Build.0 = Debug|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Release|Any CPU.Build.0 = Release|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Release|x64.ActiveCfg = Release|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Release|x64.Build.0 = Release|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Release|x86.ActiveCfg = Release|Any CPU
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -158,5 +186,7 @@ Global
 		{5565DAEA-A170-462E-B2F5-0BDD6878319C} = {0AB3BF05-4346-4AA6-1389-037BE0695223}
 		{DFDD4E5D-1418-41C2-A6CE-2A6397026499} = {17B595E7-34C1-4B92-9FD3-316E5A57E051}
 		{57855B3A-D369-4D2D-8B43-FA09549FF955} = {0AB3BF05-4346-4AA6-1389-037BE0695223}
+		{EA495C23-8110-4B63-A97D-A8C68483F9B4} = {827E0CD3-B72D-47B6-A68D-7590B98EB39B}
+		{A0D6A010-D7CD-4DFE-A011-3413544A2C9A} = {0AB3BF05-4346-4AA6-1389-037BE0695223}
 	EndGlobalSection
 EndGlobal

README.md

@@ -51,6 +51,7 @@ Every visual element — cells, headers, editors, scrollbars, popups — is rend
 - [Custom Fonts](#-custom-fonts)
 - [Scrolling & Performance](#-scrolling--performance)
 - [Live Data](#-live-data)
+- [Native AOT & Trimming](#-native-aot--trimming)
 - [Architecture](#-architecture)
 - [Sample Application](#-sample-application)
 - [Requirements](#-requirements)
@@ -88,6 +89,7 @@ Every visual element — cells, headers, editors, scrollbars, popups — is rend
 | **Theming** | Built-in Light / Dark / HighContrast; fully customisable style object |
 | **Momentum scrolling** | Physics-based inertial scroll with configurable friction |
 | **Live data** | `INotifyPropertyChanged` and `ObservableCollection` O(1) updates |
+| **Native AOT & trimming** | Warning-free under `PublishAot`; `[KumikoGridItem]` source-generated accessors or per-column delegates |
 | **Column resizing** | Drag column border |
 
 ---
@@ -815,7 +817,49 @@ public class Employee : INotifyPropertyChanged
 <core:KumikoColumn Header="City" PropertyName="Address.City" Width="120" />
 ```
 
-Accessors are compiled once via `Expression.Property` chains and cached.
+Each path segment is resolved once per item type and cached. A `null` value part-way along the path reads as an empty cell, and an edit to it is ignored. How the properties are read is covered in [Native AOT & Trimming](#-native-aot--trimming).
+
+---
+
+## 🧩 Native AOT & Trimming
+
+All KumikoUI packages are marked `IsAotCompatible` and build with no trimming or Native AOT warnings. The grid reads and writes item properties named by `PropertyName` through, in order:
+
+1. **Column delegates**: `ValueAccessor` and `ValueSetter` on `KumikoColumn` (and `EditorDisplaySelector` / `EditorValueSelector` for ComboBox items).
+2. **Generated accessors**: types marked `[KumikoGridItem]`. The `KumikoUI.Core` package includes a source generator that writes typed accessors for their public properties and registers them when the assembly loads.
+3. **Registered providers**: `KumikoAccessorRegistry.Register(type, provider)` or `AddProvider(provider)` with your own `IKumikoAccessorProvider`, for example to read dictionary entries or data rows.
+4. **Reflection**: everything else. This fallback is turned off automatically for `PublishAot=true` and `TrimMode=full`, because those publishes remove the metadata it reads. Partial trimming (the .NET MAUI default) keeps it on.
+
+With reflection off, a property that no tier can serve reads as `null`, edits to it are ignored, and a warning naming the type and property is traced once.
+
+```csharp
+using KumikoUI.Core.Data;
+
+[KumikoGridItem]          // generated accessors for Name, Age, Address, …
+public class Employee
+{
+    public string Name { get; set; } = "";
+    public int Age { get; set; }
+    public Address? Address { get; set; }
+}
+
+[KumikoGridItem]          // mark every type a path walks through ("Address.City")
+public class Address
+{
+    public string City { get; set; } = "";
+}
+
+// Or per column, without attributes:
+var bonus = new KumikoColumn
+{
+    Header = "Bonus",
+    PropertyName = "Bonus",                                   // still names the column for summaries and grouping
+    ValueAccessor = item => ((Employee)item).Age * 10m,
+    ValueSetter = (item, value) => { /* write it back */ },
+};
+```
+
+Generated accessors and delegates are faster than the expression trees the grid compiled before, and need no runtime code generation. `bench/KumikoUI.Benchmarks` measures them. The generator reports `KUMIKO001` for generic types and `KUMIKO002` for types it cannot reference (private, protected or file-local); use delegates or a provider for those. Set the `KumikoReflectionPropertyAccess` MSBuild property to `true` or `false` to override the automatic choice.
 
 ---
 

bench/KumikoUI.Benchmarks/KumikoUI.Benchmarks.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <!-- Property-access benchmarks for #17, not run in CI. See bench/README.md for how to run them. -->
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+    <IncludeSymbols>false</IncludeSymbols>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="BenchmarkDotNet" />
+    <PackageReference Remove="MinVer" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="../../src/KumikoUI.Core/KumikoUI.Core.csproj" />
+    <ProjectReference Include="../../src/KumikoUI.SourceGenerators/KumikoUI.SourceGenerators.csproj"
+                      OutputItemType="Analyzer"
+                      ReferenceOutputAssembly="false" />
+  </ItemGroup>
+
+</Project>

bench/KumikoUI.Benchmarks/Program.cs

@@ -0,0 +1,3 @@
+using BenchmarkDotNet.Running;
+
+BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).Run(args);