Add ContinueOnError support for DispatchToInnerBuilds target

src/Build.UnitTests/CrossTargetingTargets_Tests.cs

@@ -0,0 +1,79 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using Microsoft.Build.UnitTests;
+using Xunit;
+
+namespace Microsoft.Build.UnitTests
+{
+    public class CrossTargetingTargetsTests
+    {
+        private readonly ITestOutputHelper _output;
+
+        public CrossTargetingTargetsTests(ITestOutputHelper output)
+        {
+            _output = output;
+        }
+
+        [Theory]
+        [InlineData("WarnAndContinue", true, true)]
+        [InlineData("true", true, true)]
+        [InlineData("ErrorAndContinue", false, true)]
+        [InlineData("ErrorAndStop", false, false)]
+        [InlineData("false", false, false)]
+        [InlineData(null, false, false)]
+        public void DispatchToInnerBuildsCanContinueOnError(string? continueOnError, bool expectSuccess, bool expectAfterDispatch)
+        {
+            using TestEnvironment env = TestEnvironment.Create(_output);
+            TransientTestFile nugetTargets = env.CreateFile("NuGet.targets", "<Project />");
+
+            TransientTestProjectWithFiles project = env.CreateTestProjectWithFiles("""
+                <Project DefaultTargets="Test">
+                <PropertyGroup>
+                    <TargetFrameworks>failing;successful</TargetFrameworks>
+                    <InnerTargets>InnerBuild</InnerTargets>
+                    <BuildInParallel>false</BuildInParallel>
+                </PropertyGroup>
+
+                <Import Project="$(MSBuildToolsPath)\Microsoft.Common.CrossTargeting.targets" />
+
+                <Target Name="InnerBuild">
+                    <Error
+                    Condition="'$(TargetFramework)' == 'failing'"
+                    Text="INNER_FAILURE" />
+                </Target>
+
+                <Target Name="Test" DependsOnTargets="DispatchToInnerBuilds">
+                    <Message Text="AFTER_DISPATCH" Importance="High" />
+                </Target>
+                </Project>
+                """);
+
+            var globalProperties = new Dictionary<string, string>
+            {
+                ["NuGetRestoreTargets"] = nugetTargets.Path,
+            };
+
+            if (continueOnError is not null)
+            {
+                globalProperties["DispatchToInnerBuildsContinueOnError"] = continueOnError;
+            }
+
+            MockLogger logger = expectSuccess
+                ? project.BuildProjectExpectSuccess(globalProperties)
+                : project.BuildProjectExpectFailure(globalProperties);
+
+            logger.AssertLogContains("INNER_FAILURE");
+
+            if (expectAfterDispatch)
+            {
+                logger.AssertLogContains("AFTER_DISPATCH");
+            }
+            else
+            {
+                logger.AssertLogDoesntContain("AFTER_DISPATCH");
+            }
+        }
+    }
+}

src/Tasks/Microsoft.Common.CrossTargeting.targets

@@ -121,19 +121,24 @@ Copyright (C) Microsoft Corporation. All rights reserved.
      @(InnerOutput) - The combined output items of the inner targets across
                       all target frameworks..
   ============================================================
-  -->
+  -->    
   <Target Name="DispatchToInnerBuilds"
           DependsOnTargets="_ComputeTargetFrameworkItems"
           Returns="@(InnerOutput)">
     <!-- If this logic is changed, also update Clean -->
     <MSBuild Projects="@(_InnerBuildProjects)"
              Condition="'@(_InnerBuildProjects)' != '' "
              Targets="$(InnerTargets)"
-             BuildInParallel="$(BuildInParallel)">
+             BuildInParallel="$(BuildInParallel)"
+             ContinueOnError="$(DispatchToInnerBuildsContinueOnError)">
       <Output ItemName="InnerOutput" TaskParameter="TargetOutputs" />
     </MSBuild>
   </Target>
 
+  <PropertyGroup>
+    <DispatchToInnerBuildsContinueOnError Condition="'$(DispatchToInnerBuildsContinueOnError)' == ''">false</DispatchToInnerBuildsContinueOnError>
+  </PropertyGroup>
+
   <!--
   ============================================================
                                        Build