Improve handling of RuntimeIdentifier and SelfContained across projec…

…t references

src/Tasks/Microsoft.NET.Build.Tasks/ValidateExecutableReferences.cs

@@ -14,6 +14,8 @@ public class ValidateExecutableReferences : TaskBase
     {
         public bool SelfContained { get; set; }
 
+        public bool SelfContainedIsGlobalProperty { get; set; }
+
         public bool IsExecutable { get; set; }
 
         public ITaskItem[] ReferencedProjects { get; set; } = Array.Empty<ITaskItem>();
@@ -53,6 +55,14 @@ protected override void ExecuteCore()
                 bool referencedProjectIsExecutable = MSBuildUtilities.ConvertStringToBool(projectAdditionalProperties["_IsExecutable"]);
                 bool referencedProjectIsSelfContained = MSBuildUtilities.ConvertStringToBool(projectAdditionalProperties["SelfContained"]);
 
+                if (SelfContainedIsGlobalProperty && project.GetBooleanMetadata("AcceptsRuntimeIdentifier") == true)
+                {
+                    //  If AcceptsRuntimeIdentifier is true for the project, and SelfContained was set as a global property,
+                    //  then the SelfContained value will flow across the project reference when we go to build it, despite the
+                    //  fact that we ignored it when doing the GetTargetFrameworks negotiation.
+                    referencedProjectIsSelfContained = SelfContained;
+                }
+
                 if (referencedProjectIsExecutable && shouldBeValidatedAsExecutableReference)
                 {
                     if (SelfContained && !referencedProjectIsSelfContained)

src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets

@@ -22,6 +22,15 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <PropertyGroup>
     <_IsExecutable Condition="'$(OutputType)' == 'Exe' or '$(OutputType)'=='WinExe'">true</_IsExecutable>
+
+  </PropertyGroup>
+
+  <!-- Set the AcceptsRuntimeIdentifier property if this project should accept global RuntimeIdentifier and SelfContained
+       property values from referencing projects. -->
+  <PropertyGroup Condition="'$(AcceptsRuntimeIdentifier)' == ''">
+    <AcceptsRuntimeIdentifier Condition="'$(_IsExecutable)' == 'true' Or
+                                         '$(RuntimeIdentifier)' != '' Or
+                                         '$(RuntimeIdentifiers)' != ''">true</AcceptsRuntimeIdentifier>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(HasRuntimeOutput)' == ''">

src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets

@@ -1096,12 +1096,25 @@ Copyright (c) .NET Foundation. All rights reserved.
     <_UseAttributeForTargetFrameworkInfoPropertyNames Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MSBuildVersion), '17.0'))">true</_UseAttributeForTargetFrameworkInfoPropertyNames>
   </PropertyGroup>
 
+  <PropertyGroup>
+    <!-- Check if SelfContained is specified as a global property, by trying to change its value and seeing if that's successful.
+         We need to know if it's a global property because if it is, then it will flow to referenced projects that had
+         AcceptsRuntimeIdentifier set to true, possibly overriding the value for SelfContained that we got back from
+         the GetTargetFrameworks negotiation. -->
+    <_SelfContainedBackupValue>$(SelfContained)</_SelfContainedBackupValue>
+    <SelfContained>NotAValue</SelfContained>
+    <_SelfContainedIsGlobalProperty Condition="'$(SelfContained)' == '$(_SelfContainedBackupValue)'">true</_SelfContainedIsGlobalProperty>
+    <SelfContained>$(_SelfContainedBackupValue)</SelfContained>
+    <_SelfContainedBackupValue></_SelfContainedBackupValue>
+  </PropertyGroup>
+
   <Target Name="ValidateExecutableReferences"
           AfterTargets="_GetProjectReferenceTargetFrameworkProperties"
           Condition="'$(ValidateExecutableReferencesMatchSelfContained)' != 'false'">
 
     <ValidateExecutableReferences
       SelfContained="$(SelfContained)"
+      SelfContainedIsGlobalProperty="$(_SelfContainedIsGlobalProperty)"
       IsExecutable="$(_IsExecutable)"
       ReferencedProjects="@(_MSBuildProjectReferenceExistent)"
       UseAttributeForTargetFrameworkInfoPropertyNames="$(_UseAttributeForTargetFrameworkInfoPropertyNames)"