From c0d7b2cfe92dd17578a381e890baa6308363c60d Mon Sep 17 00:00:00 2001
From: Stephane Delcroix <stephane@delcroix.org>
Date: Mon, 27 Jul 2026 16:44:00 +0200
Subject: [PATCH] Turn XAML Incremental Hot Reload (XIHR) off by default

XIHR was enabled by default for Debug builds, which caused issues.
Make it opt-in instead: EnableMauiIncrementalHotReload now defaults to
false unless the developer explicitly sets it to true. Legacy XAML Hot
Reload remains the default fallback.

The runtime feature switch (IsIncrementalHotReloadEnabledByDefault) is
already false, so this makes the MSBuild default coherent with the
runtime default end-to-end.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 78048f76-1e94-4d6a-b306-7d8c74ddea9f
---
 .../netstandard2.0/Microsoft.Maui.Controls.targets   | 12 +++++-------
 .../tests/Xaml.UnitTests/MSBuild/MSBuildTests.cs     |  2 +-
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/Controls/src/Build.Tasks/nuget/buildTransitive/netstandard2.0/Microsoft.Maui.Controls.targets b/src/Controls/src/Build.Tasks/nuget/buildTransitive/netstandard2.0/Microsoft.Maui.Controls.targets
index d3766c044a71..0083977834db 100644
--- a/src/Controls/src/Build.Tasks/nuget/buildTransitive/netstandard2.0/Microsoft.Maui.Controls.targets
+++ b/src/Controls/src/Build.Tasks/nuget/buildTransitive/netstandard2.0/Microsoft.Maui.Controls.targets
@@ -10,13 +10,11 @@
     <_MauiXamlInflator Condition="' $(MauiXamlInflator)' != '' ">$(MauiXamlInflator)</_MauiXamlInflator>
     <_MauiXamlInflator Condition=" '$(MauiXamlInflator)' == '' ">SourceGen</_MauiXamlInflator>
 
-    <!-- XAML Incremental Hot Reload (XIHR): on by default for .NET 11 projects (Preview 7). Hot reload is a
-         dev-time feature; when enabled it emits per-page registry calls and keeps the runtime feature
-         switch on, so it defaults on for Debug builds only and stays off for Release/publish, where the
-         registry calls and runtime switch trim away. Set <EnableMauiIncrementalHotReload>false</...> to
-         opt out (legacy XAML Hot Reload remains available as a fallback). Resolves to an explicit
-         true/false so the value always flows to the source generator and runtime config. -->
-    <EnableMauiIncrementalHotReload Condition="'$(EnableMauiIncrementalHotReload)' == '' and '$(Configuration)' == 'Debug'">true</EnableMauiIncrementalHotReload>
+    <!-- XAML Incremental Hot Reload (XIHR): off by default. Hot reload is a dev-time feature; when
+         enabled it emits per-page registry calls and keeps the runtime feature switch on. Set
+         <EnableMauiIncrementalHotReload>true</...> to opt in (legacy XAML Hot Reload remains the
+         default fallback). Resolves to an explicit true/false so the value always flows to the source
+         generator and runtime config. -->
     <EnableMauiIncrementalHotReload Condition="'$(EnableMauiIncrementalHotReload)' == ''">false</EnableMauiIncrementalHotReload>
 
     <!-- XAML Hot Reload mode for IDE communication (Legacy or SourceGen) -->
diff --git a/src/Controls/tests/Xaml.UnitTests/MSBuild/MSBuildTests.cs b/src/Controls/tests/Xaml.UnitTests/MSBuild/MSBuildTests.cs
index 472f3dce1a04..fa82c0d92690 100644
--- a/src/Controls/tests/Xaml.UnitTests/MSBuild/MSBuildTests.cs
+++ b/src/Controls/tests/Xaml.UnitTests/MSBuild/MSBuildTests.cs
@@ -310,7 +310,7 @@ public void HotReloadSupportForXSG(string configuration)
 			project.Save(projectFile);
 			// Pin XIHR off: this test covers the legacy ResourceProvider2 hot-reload fallback
 			// (InitializeComponentRuntime), which XAML Incremental Hot Reload intentionally supersedes
-			// when enabled (on by default in Debug). See dotnet/maui#36682.
+			// when enabled. XIHR is off by default (opt-in), but pin it explicitly here. See dotnet/maui#36682.
 			Build(projectFile, additionalArgs: $"-c {configuration} -p:MauiXamlInflator=SourceGen -p:EnableMauiIncrementalHotReload=false -p:EmitCompilerGeneratedFiles=True -p:CompilerGeneratedFilesOutputPath=Generated");
 
 			var generatorDirectory = IOPath.Combine(tempDirectory, "Generated", "Microsoft.Maui.Controls.SourceGen", "Microsoft.Maui.Controls.SourceGen.XamlGenerator");