Merge remote-tracking branch 'agocke/set-trimmode-partial' into net7.0-a-new-hope

dotnet/targets/Xamarin.Shared.Sdk.props

@@ -18,6 +18,8 @@
 		<_XamarinTaskAssembly Condition="'$(_PlatformName)' != 'macOS'">$(_XamarinSdkRootDirectory)\tools\msbuild\iOS\Xamarin.iOS.Tasks.dll</_XamarinTaskAssembly>
 		<_XamarinTaskAssembly Condition="'$(_PlatformName)' == 'macOS'">$(_XamarinSdkRootDirectory)\tools\msbuild\macOS\Xamarin.Mac.Tasks.dll</_XamarinTaskAssembly>
 		<SuppressTrimAnalysisWarnings Condition=" '$(SuppressTrimAnalysisWarnings)' == '' ">true</SuppressTrimAnalysisWarnings>
+		<!-- For compat with user code not marked trimmable, only trim opt-in by default. -->
+		<TrimMode Condition="'$(TrimMode)' == ''">partial</TrimMode>
 		<AfterMicrosoftNETSdkTargets>$(AfterMicrosoftNETSdkTargets);$(MSBuildThisFileDirectory)Microsoft.$(_PlatformName).Sdk.targets</AfterMicrosoftNETSdkTargets>
 
 		<!-- _XamarinSdkRoot is used by the existing MSBuild targets files -->

dotnet/targets/Xamarin.Shared.Sdk.targets

@@ -451,9 +451,10 @@
 
 			<!-- TrimMode specifies what the linker will do with framework assemblies -->
 			<TrimMode Condition="'$(_LinkMode)' == 'TrimMode'">$(TrimMode)</TrimMode>
-			<TrimMode Condition="'$(_LinkMode)' == 'None'">copy</TrimMode> <!-- Don't use 'copyused', because that might still end up saving some assemblies, and if that's the platform assembly, it may break the partial static registrar -->
-			<TrimMode Condition="'$(_LinkMode)' == 'SdkOnly' Or '$(_LinkMode)' == 'Full'">link</TrimMode>
-			<!-- For Full link mode we also need to set TrimMode for all non-framework assemblies. This is done further below -->
+			<TrimMode Condition="'$(_LinkMode)' == 'None'">copy</TrimMode>
+			<TrimMode Condition="'$(_LinkMode)' == 'SdkOnly'">partial</TrimMode>
+			<TrimMode Condition="'$(_LinkMode)' == 'Full'">full</TrimMode>
+			<!-- For None link mode we also need to set TrimMode for all assemblies. This is done further below -->
 
 			<!-- Determine if any assemblies are actually trimmed, or if we're in a "Don't link" scenario -->
 			<!-- We're in a "Don't link" scenario if both of the following are true:
@@ -562,12 +563,12 @@
 		</PropertyGroup>
 
 		<ItemGroup>
-			<!-- Mark all assemblies to be linked if we're linking all assemblies -->
+			<!-- Mark all assemblies to be copied if we're not linking any assemblies -->
 			<ResolvedFileToPublish
 				Update="@(ResolvedFileToPublish)"
-				Condition="'$(_LinkMode)' == 'Full' And '%(ResolvedFileToPublish.Extension)' == '.dll' And '%(ResolvedFileToPublish.AssetType)' != 'native'"
+				Condition="'$(_LinkMode)' == 'None' And '%(ResolvedFileToPublish.Extension)' == '.dll' And '%(ResolvedFileToPublish.AssetType)' != 'native'"
 			>
-				<TrimMode>link</TrimMode>
+				<TrimMode>copy</TrimMode> <!-- Don't use 'copyused', because that might still end up saving some assemblies, and if that's the platform assembly, it may break the partial static registrar -->
 			</ResolvedFileToPublish>
 
 			<!-- Mark our entry assembly as a root assembly. -->

msbuild/Xamarin.iOS.Tasks.Windows/Xamarin.iOS.Common.After.targets

@@ -330,7 +330,7 @@ Copyright (C) 2011-2013 Xamarin. All rights reserved.
 				ReferenceAssemblyPaths="@(ReferencePath)"
 				RootAssemblyNames="@(TrimmerRootAssembly)"
 				TrimMode="$(TrimMode)"
-				DefaultAction="$(TrimmerDefaultAction)"
+				DefaultAction="$(_TrimmerDefaultAction)"
 				RemoveSymbols="$(TrimmerRemoveSymbols)"
 				FeatureSettings="@(_TrimmerFeatureSettings)"
 				CustomData="@(_TrimmerCustomData)"