NativeAOT deployment

docs/TOC.yml

@@ -1172,6 +1172,8 @@
               href: ios/hot-restart.md
             - name: Wireless deployment
               href: ios/wireless-deployment.md
+        - name: Native AOT
+          href: deployment/nativeaot.md
         - name: Project configuration
           href: deployment/visual-studio-properties.md
         - name: Publish

docs/deployment/nativeaot.md

@@ -0,0 +1,141 @@
+---
+title: "Native AOT deployment on iOS and Mac Catalyst"
+description: "Learn how to reduce your app size and achieve faster startup time with native AOT deployment on iOS and Mac Catalyst."
+ms.date: 10/24/2024
+monikerRange: ">=net-maui-9.0"
+---
+
+# Native AOT deployment on iOS and Mac Catalyst
+
+Native ahead-of-time (AOT) deployment produces a .NET Multi-platform App UI (.NET MAUI) app on iOS and Mac Catalyst that's been ahead-of-time compiled to native code. Native AOT performs static program analysis, full trimming of your app, which is aggressive in removing code that's not statically referenced, and ahead-of-time code generation.
+
+Publishing and deploying a Native AOT app produces the following benefits:
+
+- Reduced app package size.
+- Faster startup time.
+- Faster build time.
+
+Native AOT will introduce limitations on usage of certain aspects of the .NET runtime, and should only be used in scenarios where app size and performance are important. It'll require you to adapt your apps to Native AOT requirements, which means ensuring that they are fully trimming and AOT compatible. For more information about Native AOT limitations, see [Native AOT limitations](#native-aot-limitations).
+
+When Native AOT deployment is enabled, the build system analyzes your code, and all its dependencies, to verify if it's suitable for full trimming and AOT compilation. If incompatibilities are detected, trimming and AOT warnings are produced. A single trimming or AOT warning means that the app isn't compatible with Native AOT deployment, and that it might not work correctly. Therefore, when building an app for Native AOT deployment you should review and correct all trimming and AOT warnings. Failure to do this may result in exceptions at runtime since necessary code could have been removed. If you suppress the warnings the AOT deployed app must be thoroughly tested to verify that functionality hasn't changed from the untrimmed app. For more information, see [Introduction to trim warnings](/dotnet/core/deploying/trimming/fixing-warnings) and [Introduction to AOT warnings](/dotnet/core/deploying/native-aot/fixing-warnings).
+
+> [!NOTE]
+> There may be cases where fixing trimming and AOT warnings isn't possible, such as when they occur for third-party libraries. In such cases, third-party libraries will need to be updated to become fully compatible.
+
+## Native AOT performance benefits
+
+Publishing and deployment a Native AOT app produces an app that's typically up to 2.5x smaller, and an app that starts up typically up to 2x faster.
+
+The following chart shows the resulting app package size for a `dotnet new maui` app on iOS and Mac Catalyst across different deployment models:
+
+:::image type="content" source="media/nativeaot/app-package-size.png" alt-text="Chart showing app package size across different deployment models." border="false":::
+
+The preceding chart shows that Native AOT produces more than 2x smaller apps for both iOS and Mac Catalyst compared to the default deployment model.
+
+The following chart shows the average startup time for a `dotnet new maui` app on iOS and Mac Catalyst on Mono and Native AOT deployment:
+
+:::image type="content" source="media/nativeaot/average-startup-time.png" alt-text="Chart showing average app startup time on Mono and Native AOT." border="false":::
+
+The preceding chart shows that Native AOT has up to 2x faster startup times on iOS devices and 1.2x faster startup time on Mac Catalyst, compared to Mono deployment.
+
+The following chart shows the average build time for a `dotnet new maui` app on iOS and Mac Catalyst across different deployment models:
+
+:::image type="content" source="media/nativeaot/average-build-time.png" alt-text="Chart showing average app build time on Mono and Native AOT." border="false":::
+
+The preceding chart shows that Native AOT has up to 2.8x faster build times on iOS devices compared to the default deployment model. For Mac Catalyst, build times are comparable for arm64 single RID apps, but are slightly slower for universal apps when compared to Mono deployment.
+
+> [!IMPORTANT]
+> In many scenarios Native AOT will produce smaller and faster apps. However, in some scenarios Native AOT might not produce smaller and faster apps. Therefore, it's important to test and profile your app to determine the result of enabling Native AOT deployment.
+
+## Publish using Native AOT
+
+The Native AOT deployment model is enabled with the `$(PublishAot)` build property, and the `dotnet publish` command. The following example shows how to modify a project file to enable Native AOT deployment on iOS and Mac Catalyst:
+
+```xml
+<PropertyGroup>
+  <!-- enable trimming and AOT analyzers on all platforms -->
+  <IsAotCompatible>true</IsAotCompatible>
+
+  <!-- select platforms to use with NativeAOT -->
+  <PublishAot Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'ios'">true</PublishAot>
+  <PublishAot Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'maccatalyst'">true</PublishAot>
+</PropertyGroup>
+```
+
+Setting the `$(IsAotCompatible)` build property to `true`, for all platforms, enables trimming and AOT analyzers. These analyzers help you identify code that's not compatible with trimming or AOT.
+
+Conditionally setting `$(PublishAot)` to `true`, for iOS and Mac Catalyst, enables dynamic code usage analysis during build and Native AOT compilation during publish. Native AOT analysis includes all of the app's code and any libraries the app depends on.
+
+> [!WARNING]
+> The `$(PublishAot)` build property shouldn't be conditioned by build configuration. This is because trimming features switches are enabled or disabled based on the value of the `$(PublishAot)` build property, and the same features should be enabled or disabled in all build configurations so that your code behaves identically. For more information about trimming feature switches, see [Trimming feature switches](trimming.md#trimming-feature-switches).
+
+The only way to verify that a Native AOT app works correctly is to publish it using `dotnet publish` and verify that there are no trimming or AOT warnings produced by your code and its dependencies. In particular, `dotnet build -t:Publish` isn't equivalent to `dotnet publish`.
+
+Use the following `dotnet publish` command to publish your app on iOS and Mac Catalyst using Native AOT deployment:
+
+```dotnetcli
+# iOS
+dotnet publish -f net9.0-ios -r ios-arm64
+
+# Mac Catalyst
+dotnet publish -f net9.0-maccatalyst -r maccatalyst-arm64
+dotnet publish -f net9.0-maccatalyst -r maccatalyst-x64
+
+# Universal Mac Catalyst apps
+# (when <RuntimeIdentifiers>maccatalyst-x64;maccatalyst-arm64</RuntimeIdentifiers> is set in the project file)
+dotnet publish -f net9.0-maccatalyst
+```
+
+> [!TIP]
+> Publish apps frequently to discover trimming or AOT issues early in the development lifecycle.
+
+## Native AOT limitations
+
+Native AOT will introduce limitations on usage of certain aspects of the .NET runtime, and should only be used in scenarios where app size and performance are important. It'll require you to adapt your apps to Native AOT requirements, which means ensuring that they are fully trimming and AOT compatible, and this can require a lot of work. In addition to the [.NET limitations of Native AOT deployment](/dotnet/core/deploying/native-aot/?tabs=windows%2Cnet8#limitations-of-native-aot-deployment), Native AOT deployment for .NET MAUI has additional limitations.
+
+Third-party libraries your apps depend on might not be AOT compatible. The only way to ensure that a library is trimming and AOT compatible is to publish your app using Native AOT deployment and the `dotnet publish` command, and see if the Native AOT compiler produces any warnings for the library. For information about making your own libraries AOT compatible, see [How to make libraries compatible with native AOT](https://devblogs.microsoft.com/dotnet/creating-aot-compatible-libraries/).
+
+### Reflection and dynamic code
+
+Native AOT deployment limits the use of reflection in your code and its dependencies, and it can become necessary to use annotations to help the Native AOT compiler understand reflection patterns. When the compiler encounters a reflection pattern it can't statically analyze, and hence can't build the app, it produces trim warnings. Native AOT also prevents you from using dynamic code in your app. For example, compiling <xref:System.Linq.Expressions> won't work as expected, and it isn't possible to load and execute assemblies at runtime. When the compiler encounters a dynamic pattern it can't ahead-of-time compile, it will produce an AOT warning.
+
+In .NET MAUI app this means that:
+
+- All XAML needs to be ahead-of-time compiled. Therefore, ensure that you haven't disabled XAML compilation, and that all bindings are compiled. For more information, see [XAML compilation](~/xaml/xamlc.md) and [Compiled bindings](~/fundamentals/data-binding/compiled-bindings.md).
+- All binding expressions must use compiled bindings, rather than a binding path that's set to a string. For more information, see [Compiled bindings](~/fundamentals/data-binding/compiled-bindings.md).
+- Implicit conversion operators might not be called when assigning a value of an incompatible type to a property in XAML, or when two properties of different types use a data binding. Instead, you should define a <xref:System.ComponentModel.TypeConverter> for your type and attach it to the type using the <xref:System.ComponentModel.TypeConverterAttribute>. For more information, see [Define a TypeConverter to replace an implicit conversion operator](trimming.md#define-a-typeconverter-to-replace-an-implicit-conversion-operator).
+- It's not possible to parse XAML at runtime with the <xref:Microsoft.Maui.Controls.Xaml.Extensions.LoadFromXaml%2A> method. While this can be made trim safe by annotating all types that could be loaded at runtime with the [`DynamicallyAccessedMembers`](xref:System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute) attribute or the [`DynamicDependency`](xref:System.Diagnostics.CodeAnalysis.DynamicDependencyAttribute) attribute this is very error prone and isn't recommended.
+- Receiving navigation data using the <xref:Microsoft.Maui.Controls.QueryPropertyAttribute> won't work. Instead, you should implement the <xref:Microsoft.Maui.Controls.IQueryAttributable> interface on types that need to accept query parameters. For more information, see [Process navigation data using a single method](~/fundamentals/shell/navigation.md#process-navigation-data-using-a-single-method).
+- The `SearchHandler.DisplayMemberName` property might not work. Instead, you should provide an <xref:Microsoft.Maui.Controls.ItemsView.ItemTemplate> to define the appearance of <xref:Microsoft.Maui.Controls.SearchHandler> results. For more information, see [Define search results item appearance](~/fundamentals/shell/search.md#define-search-results-item-appearance).
+
+> [!IMPORTANT]
+> The Mono interpreter isn't compatible with Native AOT deployment, and therefore the `$(UseInterpreter)` and `$(MtouchInterpreter)` MSBuild properties have no effect when using Native AOT. For more information about the Mono interpreter, see [Mono interpreter on iOS and Mac Catalyst](~/macios/interpreter.md).
+
+For more information about trim warnings, see [Introduction to trim warnings](/dotnet/core/deploying/trimming/fixing-warnings). For more information about AOT warnings, see [Introduction to AOT warnings](/dotnet/core/deploying/native-aot/fixing-warnings).
+
+## Adapt an app to Native AOT deployment
+
+Use the following checklist to help you adapt your app to Native AOT deployment requirements:
+
+> [!div class="checklist"]
+>
+> - Ensure that all XAML is compiled:
+>   - Remove all `[XamlCompilation(XamlCompilationOptions.Skip)]` usage.
+>   - Remove all `<?xaml-comp compile="false" ?>` usage.
+> - Remove all calls to the <xref:Microsoft.Maui.Controls.Xaml.Extensions.LoadFromXaml%2A> method.
+> - Ensure that all data bindings are compiled. For more information, see [Compiled bindings](~/fundamentals/data-binding/compiled-bindings.md).
+>   - Ensure that all XAML data bindings are annotated with `x:DataType`.
+>   - Ensure that all code data bindings replace all string-based bindings with lambda-based bindings.
+> - Replace all `[QueryProperty(...)]` usage with an implementation of the `IQueryAttributable` interface. For more information, see [Process navigation data using a single method](~/fundamentals/shell/navigation.md#process-navigation-data-using-a-single-method).
+> - Replace all `SearchHandler.DisplayMemberName` usage with an <xref:Microsoft.Maui.Controls.ItemsView.ItemTemplate>. For more information, see [Define search results item appearance](~/fundamentals/shell/search.md#define-search-results-item-appearance).
+> - Replace all implicit conversion operators for types used in XAML with a <xref:System.ComponentModel.TypeConverter>, and it attach it to your type using the <xref:System.ComponentModel.TypeConverterAttribute>. For more information, see [Define a TypeConverter to replace an implicit conversion operator](trimming.md#define-a-typeconverter-to-replace-an-implicit-conversion-operator).
+>   - When converting from type `A` to type `B`, either the `ConvertTo` method on a type converter associated with `A` will be used or the `ConvertFrom` method on a type converter associated with `B` will be used.
+>   - When both source and target types have an associated type converter, either of them can be used.
+> - Compile all regular expressions using source generators. For more information, see [.NET regular expression source generators](/dotnet/standard/base-types/regular-expression-source-generators).
+> - Ensure that JSON serialization and deserialization uses a source generated context. For more information, see [Minimal APIs and JSON payloads](/aspnet/core/fundamentals/native-aot#minimal-apis-and-json-payloads).
+> - Review and correct any trimming or AOT warnings. For more information, see [Introduction to trim warnings](/dotnet/core/deploying/trimming/fixing-warnings) and [Introduction to AOT warnings](/dotnet/core/deploying/native-aot/fixing-warnings).
+> - Thoroughly test your app.
+
+## See also
+
+- [Trim a .NET MAUI app](trimming.md)

docs/fundamentals/data-binding/compiled-bindings.md

@@ -18,7 +18,7 @@ Compiled bindings improve data binding performance in .NET MAUI applications by
 ::: moniker range=">=net-maui-9.0"
 
 > [!IMPORTANT]
-> Compiled bindings are required instead of string-based bindings in NativeAOT apps, and in apps with full trimming enabled.
+> Compiled bindings are required instead of string-based bindings in NativeAOT apps, and in apps with full trimming enabled. For more information, see [Trim a .NET MAUI app](~/deployment/trimming.md) and [Native AOT deployment](~/deployment/nativeaot.md).
 
 ::: moniker-end
 

docs/fundamentals/shell/navigation.md

@@ -438,7 +438,7 @@ In this example the first argument for the <xref:Microsoft.Maui.Controls.QueryPr
 ::: moniker range=">=net-maui-9.0"
 
 > [!WARNING]
-> Receiving navigation data using the <xref:Microsoft.Maui.Controls.QueryPropertyAttribute> isn't trim safe and shouldn't be used with full trimming or NativeAOT. Instead, you should implement the <xref:Microsoft.Maui.Controls.IQueryAttributable> interface on types that need to accept query parameters. For more information, see [Process navigation data using a single method](#process-navigation-data-using-a-single-method).
+> Receiving navigation data using the <xref:Microsoft.Maui.Controls.QueryPropertyAttribute> isn't trim safe and shouldn't be used with full trimming or NativeAOT. Instead, you should implement the <xref:Microsoft.Maui.Controls.IQueryAttributable> interface on types that need to accept query parameters. For more information, see [Process navigation data using a single method](#process-navigation-data-using-a-single-method), [Trim a .NET MAUI app](~/deployment/trimming.md), and [Native AOT deployment](~/deployment/nativeaot.md).
 
 ::: moniker-end
 
@@ -513,7 +513,7 @@ In this example, the class is decorated with a <xref:Microsoft.Maui.Controls.Que
 ::: moniker range=">=net-maui-9.0"
 
 > [!WARNING]
-> Receiving navigation data using the <xref:Microsoft.Maui.Controls.QueryPropertyAttribute> isn't trim safe and shouldn't be used with full trimming or NativeAOT. Instead, you should implement the <xref:Microsoft.Maui.Controls.IQueryAttributable> interface on types that need to accept query parameters.
+> Receiving navigation data using the <xref:Microsoft.Maui.Controls.QueryPropertyAttribute> isn't trim safe and shouldn't be used with full trimming or NativeAOT. Instead, you should implement the <xref:Microsoft.Maui.Controls.IQueryAttributable> interface on types that need to accept query parameters. For more information, see [Trim a .NET MAUI app](~/deployment/trimming.md) and [Native AOT deployment](~/deployment/nativeaot.md).
 
 ::: moniker-end
 

docs/fundamentals/shell/search.md

@@ -102,7 +102,7 @@ The `AnimalSearchHandler.OnQueryChanged` method returns a `List` of `Animal` obj
 ::: moniker range=">=net-maui-9.0"
 
 > [!WARNING]
-> `SearchHandler.DisplayMemberName` isn't trim safe and shouldn't be used with full trimming or NativeAOT. Instead, you should provide an `ItemTemplate` to define the appearance of `SearchHandler` results. For more information, see [Define search results item appearance](#define-search-results-item-appearance).
+> `SearchHandler.DisplayMemberName` isn't trim safe and shouldn't be used with full trimming or NativeAOT. Instead, you should provide an `ItemTemplate` to define the appearance of `SearchHandler` results. For more information, see [Define search results item appearance](#define-search-results-item-appearance), [Trim a .NET MAUI app](~/deployment/trimming.md) and [Native AOT deployment](~/deployment/nativeaot.md).
 
 ::: moniker-end
 

docs/index.yml

@@ -276,14 +276,14 @@ conceptualContent:
             - text: Overview
               url: deployment/index.md
               itemType: concept
-            - text: Improve app performance
-              url: deployment/performance.md
-              itemType: concept
             - text: Hot restart
               url: ios/hot-restart.md
               itemType: concept
-            - text: Wireless deployment
-              url: ios/wireless-deployment.md
+            - text: Improve app performance
+              url: deployment/performance.md
+              itemType: concept
+            - text: Native AOT
+              url: deployment/nativeaot.md
               itemType: concept
             - text: Publish Android apps
               url: android/deployment/index.md
@@ -300,6 +300,9 @@ conceptualContent:
             - text: Trimming
               url: deployment/trimming.md
               itemType: concept
+            - text: Wireless deployment
+              url: ios/wireless-deployment.md
+              itemType: concept
 
 additionalContent:
   sections: