From 514d6a9b7638bacf58672b4cdf1ee0389f22133b Mon Sep 17 00:00:00 2001
From: "Brett V. Forsgren" <brettfo@microsoft.com>
Date: Mon, 3 Mar 2025 11:31:55 -0700
Subject: [PATCH] use different values for `$(TargetPlatformVersion)` for TFM
 and dependency discovery

---
 .../Discover/SdkProjectDiscoveryTests.cs      | 45 +++++++++++++++++++
 .../Utilities/MSBuildHelperTests.cs           | 12 +++++
 .../DependencyDiscovery.props                 | 10 ++++-
 .../DependencyDiscovery.targets               |  5 +++
 4 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core.Test/Discover/SdkProjectDiscoveryTests.cs b/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core.Test/Discover/SdkProjectDiscoveryTests.cs
index 90f03bed81b..a437da0414e 100644
--- a/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core.Test/Discover/SdkProjectDiscoveryTests.cs
+++ b/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core.Test/Discover/SdkProjectDiscoveryTests.cs
@@ -479,6 +479,51 @@ await TestDiscoverAsync(
         );
     }
 
+    [Fact]
+    public async Task DependenciesCanBeDiscoveredWithWindowsSpecificTfm()
+    {
+        await TestDiscoverAsync(
+            packages:
+            [
+                MockNuGetPackage.CreateSimplePackage("Some.Dependency", "1.2.3", "netstandard2.0"),
+            ],
+            startingDirectory: "src",
+            projectPath: "src/library.csproj",
+            files:
+            [
+                ("src/library.csproj", """
+                    <Project Sdk="Microsoft.NET.Sdk">
+                      <PropertyGroup>
+                        <TargetFramework>net9.0-windows</TargetFramework>
+                      </PropertyGroup>
+                      <ItemGroup>
+                        <PackageReference Include="Some.Dependency" Version="1.2.3" />
+                      </ItemGroup>
+                    </Project>
+                    """)
+            ],
+            expectedProjects:
+            [
+                new()
+                {
+                    FilePath = "library.csproj",
+                    Dependencies =
+                    [
+                        new("Some.Dependency", "1.2.3", DependencyType.PackageReference, TargetFrameworks: ["net9.0-windows"], IsDirect: true),
+                    ],
+                    ImportedFiles = [],
+                    Properties =
+                    [
+                        new("TargetFramework", "net9.0-windows", "src/library.csproj"),
+                    ],
+                    TargetFrameworks = ["net9.0-windows"],
+                    ReferencedProjectPaths = [],
+                    AdditionalFiles = [],
+                },
+            ]
+        );
+    }
+
     private static async Task TestDiscoverAsync(string startingDirectory, string projectPath, TestFile[] files, ImmutableArray<ExpectedSdkProjectDiscoveryResult> expectedProjects, MockNuGetPackage[]? packages = null)
     {
         using var testDirectory = await TemporaryDirectory.CreateWithContentsAsync(files);
diff --git a/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core.Test/Utilities/MSBuildHelperTests.cs b/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core.Test/Utilities/MSBuildHelperTests.cs
index cc261755fc8..3d2d5a08596 100644
--- a/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core.Test/Utilities/MSBuildHelperTests.cs
+++ b/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core.Test/Utilities/MSBuildHelperTests.cs
@@ -606,6 +606,18 @@ public static IEnumerable<object[]> GetTargetFrameworkValuesFromProjectData()
             new[] { "net8.0-windows7.0" }
         ];
 
+        yield return
+        [
+            """
+            <Project Sdk="Microsoft.NET.Sdk">
+              <PropertyGroup>
+                <TargetFramework>net9.0-windows</TargetFramework>
+              </PropertyGroup>
+            </Project>
+            """,
+            new[] { "net9.0-windows" }
+        ];
+
         // legacy projects
         yield return
         [
diff --git a/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core/DependencyDiscovery.props b/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core/DependencyDiscovery.props
index cec5322a187..decaca93d19 100644
--- a/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core/DependencyDiscovery.props
+++ b/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core/DependencyDiscovery.props
@@ -1,8 +1,16 @@
 <Project>
   <!-- The following properties enable target framework and dependency discovery when OS-specific workloads are required -->
   <PropertyGroup>
+    <!--
+
+    $(TargetPlatformVersion) should default to '0.0' as per https://github.com/dotnet/sdk/blob/v9.0.100/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets#L69
+
+    HOWEVER, this will need to be set differently (e.g., '1.0') to do dependency discovery
+
+    -->
+    <_DefaultTargetPlatformVersion Condition="'$(_DefaultTargetPlatformVersion)' == ''">0.0</_DefaultTargetPlatformVersion>
     <DesignTimeBuild>true</DesignTimeBuild>
     <EnableWindowsTargeting Condition="$(TargetFramework.Contains('-windows'))">true</EnableWindowsTargeting>
-    <TargetPlatformVersion Condition="$(TargetPlatformVersion) == '' AND $(TargetFramework.Contains('-'))">1.0</TargetPlatformVersion>
+    <TargetPlatformVersion Condition="$(TargetPlatformVersion) == '' AND $(TargetFramework.Contains('-'))">$(_DefaultTargetPlatformVersion)</TargetPlatformVersion>
   </PropertyGroup>
 </Project>
\ No newline at end of file
diff --git a/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core/DependencyDiscovery.targets b/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core/DependencyDiscovery.targets
index 65ba7d4bbd7..10237b0e632 100644
--- a/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core/DependencyDiscovery.targets
+++ b/nuget/helpers/lib/NuGetUpdater/NuGetUpdater.Core/DependencyDiscovery.targets
@@ -1,4 +1,9 @@
 <Project>
+  <PropertyGroup>
+    <!-- Dependency discovery requires a non-zero value for $(TargetPlatformVersion) -->
+    <_DefaultTargetPlatformVersion>1.0</_DefaultTargetPlatformVersion>
+  </PropertyGroup>
+
   <Import Project="DependencyDiscovery.props" />
 
   <Target Name="_DiscoverDependencies" DependsOnTargets="ResolveAssemblyReferences;GenerateBuildDependencyFile;ResolvePackageAssets">