Ignore '_._' files when considering a package's build files

src/Tasks/CollectDeclaredReferencesTask.cs

@@ -266,7 +266,7 @@ private Dictionary<string, PackageInfo> GetPackageInfos()
 
             List<string> nugetLibraryAssemblies = nugetLibrary.CompileTimeAssemblies
                 .Select(item => item.Path)
-                .Where(path => !path.EndsWith("_._", StringComparison.Ordinal)) // Ignore special packages
+                .Where(IsValidFile)
                 .Select(path =>
                 {
                     var fullPath = Path.Combine(nugetLibraryAbsolutePath, path);
@@ -275,7 +275,9 @@ private Dictionary<string, PackageInfo> GetPackageInfos()
                 .ToList();
 
             List<string> buildFiles = nugetLibrary.Build
-                .Select(item => Path.Combine(nugetLibraryAbsolutePath, item.Path))
+                .Select(item => item.Path)
+                .Where(IsValidFile)
+                .Select(path => Path.Combine(nugetLibraryAbsolutePath, path))
                 .ToList();
 
             // Add this package's assets, if there are any
@@ -323,6 +325,8 @@ private Dictionary<string, PackageInfo> GetPackageInfos()
         return packageInfos;
     }
 
+    private static bool IsValidFile(string path) => !path.EndsWith("_._", StringComparison.Ordinal);
+
     private HashSet<string> GetTargetFrameworkAssemblyNames()
     {
         HashSet<string> targetFrameworkAssemblyNames = new();

src/Tests/E2ETests.cs

@@ -507,6 +507,17 @@ public Task WpfApp()
             expectedWarnings: []);
     }
 
+    [TestMethod]
+    public Task PackageReferenceWithFakeBuildFile()
+    {
+        return RunMSBuildAsync(
+            projectFile: "Library/Library.csproj",
+            expectedWarnings:
+            [
+                new Warning("RT0003: PackageReference Microsoft.Extensions.Primitives can be removed", "Library/Library.csproj"),
+            ]);
+    }
+
     private static (string ExePath, string Verb) GetMsBuildExeAndVerb()
     {
         // On Windows, try to find Visual Studio

src/Tests/TestData/PackageReferenceWithFakeBuildFile/Library/Library.cs

@@ -0,0 +1,7 @@
+namespace Library
+{
+    public static class Foo
+    {
+        public static string Bar() => Newtonsoft.Json.JsonConvert.SerializeObject(null);
+    }
+}

src/Tests/TestData/PackageReferenceWithFakeBuildFile/Library/Library.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net472</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
+    <PackageReference Include="Microsoft.Extensions.Primitives" Version="8.0.0" />
+  </ItemGroup>
+
+</Project>