Updating my project to net10 and uno 6.4 getting IL warnings on ios and other image issues

[cconner100]

Current behavior 🐛

Upgraded an existing project from net9 to net10 and uno 6.4. On iOS builds i get the following warnings which did not appear in the pervious release

/Users/curtisconner/ZiiDMS-NextGen/Client/Icons/IconLibrary/obj/Debug/net10.0-ios/unoresizetizer/r/Assets/Backgrounds/ziidmsdashboardbackground.png : warning MT7156: The BundleResource item '/Users/curtisconner/ZiiDMS-NextGen/Client/Icons/IconLibrary/obj/Debug/net10.0-ios/unoresizetizer/r/Assets/Backgrounds/ziidmsdashboardbackground.png' was ignored, because there's another item with the same LogicalName ('IconLibrary/Assets/Backgrounds/ziidmsdashboardbackground.png')
/Users/curtisconner/ZiiDMS-NextGen/Client/Icons/IconLibrary/obj/Debug/net10.0-ios/unoresizetizer/r/Assets/Backgrounds/ziidmsdashboardbackground.scale-100.png : warning MT7156: The BundleResource item '/Users/curtisconner/ZiiDMS-NextGen/Client/Icons/IconLibrary/obj/Debug/net10.0-ios/unoresizetizer/r/Assets/Backgrounds/ziidmsdashboardbackground.scale-100.png' was ignored, because there's another item with the same LogicalName ('IconLibrary/Assets/Backgrounds/ziidmsdashboardbackground.png')
(truncated since this is done for every png in my system)
/Users/curtisconner/.nuget/packages/system.configuration.configurationmanager/9.0.4/lib/net9.0/System.Configuration.ConfigurationManager.dll : warning IL2104: Assembly 'System.Configuration.ConfigurationManager' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.communitytoolkit.winui.ui.controls.datagrid/7.1.204/lib/net7.0/CommunityToolkit.WinUI.UI.Controls.DataGrid.dll : warning IL2104: Assembly 'CommunityToolkit.WinUI.UI.Controls.DataGrid' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.core.extensions/4.1.1/lib/net7.0/Uno.Core.Extensions.dll : warning IL2104: Assembly 'Uno.Core.Extensions' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.extensions.core/7.0.4/lib/net8.0/Uno.Extensions.Core.dll : warning IL2104: Assembly 'Uno.Extensions.Core' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.extensions.http/7.0.4/lib/net8.0/Uno.Extensions.Http.dll : warning IL2104: Assembly 'Uno.Extensions.Http' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.extensions.navigation.winui/7.0.4/lib/net8.0/Uno.Extensions.Navigation.UI.dll : warning IL2104: Assembly 'Uno.Extensions.Navigation.UI' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.extensions.navigation/7.0.4/lib/net8.0/Uno.Extensions.Navigation.dll : warning IL2104: Assembly 'Uno.Extensions.Navigation' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.foundation/6.4.185/lib/net10.0-ios26.0/Uno.Foundation.dll : warning IL2104: Assembly 'Uno.Foundation' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.toolkit.winui/8.3.2/lib/net9.0/Uno.Toolkit.WinUI.dll : warning IL2104: Assembly 'Uno.Toolkit.WinUI' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.app.mcp/1.0.9/lib/net9.0/Uno.UI.App.Mcp.Client.dll : warning IL2104: Assembly 'Uno.UI.App.Mcp.Client' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0-ios18.0/Uno.UI.HotDesign.Abstractions.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Abstractions'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0-ios18.0/Uno.UI.HotDesign.Messaging.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Messaging'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0-ios18.0/Uno.UI.HotDesign.Messaging.dll : warning IL2104: Assembly 'Uno.UI.HotDesign.Messaging' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0-ios18.0/Uno.UI.HotDesign.Xaml.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Xaml'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0-ios18.0/Uno.UI.HotDesign.Xaml.dll : warning IL2104: Assembly 'Uno.UI.HotDesign.Xaml' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Chat.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Chat'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Client.Core.dll : warning IL2104: Assembly 'Uno.UI.HotDesign.Client.Core' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Client.Core.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Client.Core'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Client.dll : warning IL2104: Assembly 'Uno.UI.HotDesign.Client' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Client.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Client'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.CommunityToolkit.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.CommunityToolkit'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.CommunityToolkit.dll : warning IL2104: Assembly 'Uno.UI.HotDesign.CommunityToolkit' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Hierarchy.dll : warning IL2104: Assembly 'Uno.UI.HotDesign.Hierarchy' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Hierarchy.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Hierarchy'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.PropertyGrid.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.PropertyGrid'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.PropertyGrid.dll : warning IL2104: Assembly 'Uno.UI.HotDesign.PropertyGrid' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Stories.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Stories'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Toolbox.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Toolbox'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Xaml.Interactions.dll : warning IL2104: Assembly 'Uno.UI.HotDesign.Xaml.Interactions' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Xaml.Interactions.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Xaml.Interactions'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.ui.hotdesign/1.17.282/lib/net9.0/Uno.UI.HotDesign.Xaml.Interactivity.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'Uno.UI.HotDesign.Xaml.Interactivity'. Value must be "True".
/Users/curtisconner/.nuget/packages/uno.winui.devserver/6.4.185/uno-runtime/net10.0/skia/Uno.UI.RemoteControl.dll : warning IL2104: Assembly 'Uno.UI.RemoteControl' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.winui/6.4.185/uno-runtime/net10.0/skia/Uno.UI.dll : warning IL2104: Assembly 'Uno.UI' produced trim warnings. For more information see https://aka.ms/il2104
/Users/curtisconner/.nuget/packages/uno.winui/6.4.185/uno-runtime/net10.0/skia/Uno.Xaml.dll : warning IL2104: Assembly 'Uno.Xaml' produced trim warnings. For more information see https://aka.ms/il2104
/usr/local/share/dotnet/packs/Microsoft.NETCore.App.Runtime.Mono.iossimulator-arm64/10.0.0/runtimes/iossimulator-arm64/lib/net10.0/System.Private.Xml.dll : warning IL2104: Assembly 'System.Private.Xml' produced trim warnings. For more information see https://aka.ms/il2104

Build succeeded with 401 warning(s) in 100.8s

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attached is the binlog

net10.0-ios-Debug-iossimulator-arm64.binlog.zip

Expected behavior 🎯

should not have warnings

How to reproduce it (as minimally and precisely as possible) 🔬

No response

Workaround 🛠️

No response

Renderer 🎨

• Skia
• Native

Affected platforms 📱💻🖥️

iOS

Uno.Sdk version (and other relevant versions) 📦

6.4 and .net10

IDE version 🧑‍💻

No response

Anything else we need to know? 💬

No response

[jonpryor]

A new .NET SDK can and will add new warnings.¹

This is the case for the MT7156 warnings, which were added in 2025-June-19, i.e. after .NET 9 in 2024-November: dotnet/macios@a0e276b

While dotnet/macios@a0e276b8 is also on a the .NET 9 branch, it wasn't part of the .NET 9.0 2024-November release, and thus it may be New To You with .NET 10. It looks like that change was released 2025-Oct-15, barely a month before .NET 10: https://github.com/dotnet/macios/releases/tag/dotnet-9.0.1xx-xcode26.0-9752

Breaking changes

Resource validation

We've added validation to detect if multiple different resources targets the same location in the app bundle, in which case we'll now:

• Issue a build warning when this situation is detected.
• Not copy any of the resources into the app bundle (previous behavior was undefined, any of the resources could end up winning).

Regarding the various IL2102 and IL2104 warnings you are observing, this is because your build -- somehow -- has the $(PublishTrimmed) property set to true and the $(TrimMode) property set. This feels rather odd to me, as with:

dotnet build -v:diag net10.0-ios-Debug-iossimulator-arm64.binlog > net10.0-ios-Debug-iossimulator-arm64.binlog.txt

I see:

11:15:31.476     0>Initial Properties:
…
                   Configuration = Debug
                   ConfigurationName = Debug
                   Configurations = Debug;Release;Release-NonDataMember;Debug-DataMember
…
                   PublishTrimmed = true
…
                   TrimMode = partial

$(PublishTrimmed) is part of the initial properties, which suggests that your .csproj is setting this property. Is it?

$(TrimMode) is also in the Initial Properties section. Is it also defined in your .csproj?

In local testing with a trivial repro environment:

1. dotnet new ioslib -n myioslib then updates to Class1.cs to add:

   [assembly:System.Reflection.AssemblyMetadata("IsTrimmable", "False")]

2. dotnet new ios -n myiosapp then update myiosapp.csproj to have a @(ProjectReference) to myioslib.csproj, and update Main.cs to use myioslib.dll:

   var r = new myioslib.Class1();

In shell terms:

dotnet new ioslib -n myioslib
dotnet new ios -n myiosapp
cat >patch <<EOF
diff --git a/myiosapp/Main.cs b/myiosapp/Main.cs
index 5a00bcb..81b673c 100644
--- a/myiosapp/Main.cs
+++ b/myiosapp/Main.cs
@@ -1,5 +1,7 @@
 using myiosapp;
 
+var r = new myioslib.Class1();
+
 // This is the main entry point of the application.
 // If you want to use a different Application Delegate class from "AppDelegate"
 // you can specify it here.
diff --git a/myiosapp/myiosapp.csproj b/myiosapp/myiosapp.csproj
index 0ac8deb..4d5c5c8 100644
--- a/myiosapp/myiosapp.csproj
+++ b/myiosapp/myiosapp.csproj
@@ -12,4 +12,8 @@
     -->
     <TrimMode Condition="'$(Configuration)' == 'Release'">full</TrimMode>
   </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\myioslib\myioslib.csproj" />
+  </ItemGroup>
 </Project>
diff --git a/myioslib/Class1.cs b/myioslib/Class1.cs
index 648114f..b4c98ed 100644
--- a/myioslib/Class1.cs
+++ b/myioslib/Class1.cs
@@ -1,3 +1,5 @@
+[assembly:System.Reflection.AssemblyMetadata("IsTrimmable", "False")]
+
 namespace myioslib;
 
 public class Class1 {
EOF
git apply < patch

I observe the IL2102 warning when -p:PublishTrimmed=true -p:TrimMode=partial is used:

% dotnet build -bl myiosapp/*.csproj
# no warnings

% dotnet build -bl -p:PublishTrimmed=true myiosapp/*.csproj
# no warnings

% dotnet build -bl -p:PublishTrimmed=true -p:TrimMode=partial myiosapp/*.csproj
Restore complete (0.6s)
  myioslib net10.0-ios succeeded (0.3s) → myioslib/bin/Debug/net10.0-ios/myioslib.dll
  myiosapp net10.0-ios iossimulator-x64 succeeded with 1 warning(s) (15.6s) → myiosapp/bin/Debug/net10.0-ios/iossimulator-x64/myiosapp.dll
    …/myioslib/bin/Debug/net10.0-ios/myioslib.dll : warning IL2102: Invalid AssemblyMetadata("IsTrimmable", "False") attribute in assembly 'myioslib'. Value must be "True".

Both $(PublishTrimmed)=true and $(TrimMode)=partial are also present in your .binlog.

If I fire up a Windows VM and use https://msbuildlog.com to parse your .binlog (16 GB+ memory suggested; MSBuild Structured Log Viewer uses nearly 9GB of to read your .binlog), go to the Find in Files tab, and search for <PublishTrimmed, I see that ZiiDMS-NextGen/Directory.Build.props contains:

<Project>
	<!-- … -->
	<PropertyGroup>
  		<PublishTrimmed>true</PublishTrimmed>
  		<TrimMode>partial</TrimMode>
  		<!-- Suppress known-safe warnings -->
  	<NoWarn>$(NoWarn);IL2026;IL2067;IL2070</NoWarn>
	</PropertyGroup>
</Project>

Was that a recent change?

Using .NET 9 with -p:PublishTrimmed=true -p:TrimMode=partial also results in the IL2102 warning, so for me the most likely explanation is that ZiiDMS-NextGen/Directory.Build.props changed recently to set $(PublishTrimmed)=true and $(TrimMode)=partial for all build configurations.

I suggest updating that <PropertyGroup> to be conditional on non-Debug builds:

<PropertyGroup Condition=" '$(Configuration)' != 'Debug' ">
	<PublishTrimmed>true</PublishTrimmed>
	<TrimMode>partial</TrimMode>
</PropertyGroup>

I don't have a repro for the IL2104 warnings, but I imagine it's for the same reason as the IL2102 warnings, and if $(PublishTrimmed) were false and/or $(TrimMode) were not set, you wouldn't get them. Can you please confirm?

Footnotes

1. As a recent example for me, http://github.com/unoplatform/uno.toolkit.ui will not build under .NET 10 because NETCOREAPP isn't defined, resulting in 168 errors. (I don't know why NETCOREAPP isn't defined, and I can't reproduce this behavior elsewhere, but "simply" using the .NET 9 SDK allows unoplatform/uno.toolkit.ui to build.) ↩

[jonpryor]

Meanwhile, many of those warnings are not related to Uno, e.g.

warning IL2104: Assembly 'CommunityToolkit.WinUI.UI.Controls.DataGrid' produced trim warnings. For more information see https://aka.ms/il2104
warning IL2104: Assembly 'System.Configuration.ConfigurationManager' produced trim warnings. For more information see https://aka.ms/il2104
warning IL2104: Assembly 'System.Private.Xml' produced trim warnings. For more information see https://aka.ms/il2104

Many of the remaining warnings are related to Uno, e.g.

warning IL2104: Assembly 'Uno.Core.Extensions' produced trim warnings. For more information see https://aka.ms/il2104

Fixing trim warnings is a long and ongoing process, see e.g. #21920 and unoplatform/uno.extensions#2954. In time those should be resolved, but it will take time.

[agneszitte]

Hi @cconner100 (Cc @toon-ziiosth-dev),

Could you please let us know the urgency and impact of this issue?

If you can also please confirm whether you are still experiencing this issue lately.

Could you please retest with the latest stable Uno.Sdk version 6.5.31, to verify whether it is still happening? If it is, could you also try with the latest Uno.Sdk dev version available as well: https://www.nuget.org/packages/uno.sdk/absoluteLatest

Thank you in advance for the feedback.