add test for triggering case

Author: baronfel

src/Tests/Microsoft.NET.Build.Containers.IntegrationTests/EndToEndTests.cs

@@ -353,7 +353,7 @@ private string BuildLocalApp([CallerMemberName] string testName = "TestName", st
     public async Task EndToEnd_MultiProjectSolution()
     {
         ILogger logger = _loggerFactory.CreateLogger(nameof(EndToEnd_MultiProjectSolution));
-        DirectoryInfo newSolutionDir = new(Path.Combine(TestSettings.TestArtifactsDirectory, $"CreateNewImageTest_EndToEnd_MultiProjectSolution"));
+        DirectoryInfo newSolutionDir = new(Path.Combine(TestSettings.TestArtifactsDirectory, nameof(EndToEnd_MultiProjectSolution)));
 
         if (newSolutionDir.Exists)
         {
@@ -431,6 +431,82 @@ public async Task EndToEnd_MultiProjectSolution()
         commandResult.Should().HaveStdOutContaining("Pushed image 'consoleapp:latest'");
     }
 
+    /// <summary>
+    /// Tests that a multi-project solution with a library that targets multiple frameworks can be published.
+    /// This is interesting because before https://github.com/dotnet/sdk/pull/47693 the container targets
+    /// wouldn't be loaded for multi-TFM project evaluations, so any calls to the PublishContainer target
+    /// for libraries (which may be multi-targeted even when referenced from a single-target published app project) would fail.
+    /// It's safe to load the target for libraries in a multi-targeted context because libraries don't have EnableSdkContainerSupport
+    /// enabled by default, so the target will be skipped.
+    /// </summary>
+    [DockerAvailableFact]
+    public async Task EndToEnd_MultiProjectSolution_with_multitargeted_library()
+    {
+        ILogger logger = _loggerFactory.CreateLogger(nameof(EndToEnd_MultiProjectSolution_with_multitargeted_library));
+        DirectoryInfo newSolutionDir = new(Path.Combine(TestSettings.TestArtifactsDirectory, nameof(EndToEnd_MultiProjectSolution_with_multitargeted_library)));
+
+        if (newSolutionDir.Exists)
+        {
+            newSolutionDir.Delete(recursive: true);
+        }
+
+        newSolutionDir.Create();
+
+        // Create solution with projects
+        new DotnetNewCommand(_testOutput, "sln", "-n", nameof(EndToEnd_MultiProjectSolution_with_multitargeted_library))
+            .WithVirtualHive()
+            .WithWorkingDirectory(newSolutionDir.FullName)
+            .Execute()
+            .Should().Pass();
+
+        new DotnetNewCommand(_testOutput, "web", "-n", "WebApp")
+            .WithVirtualHive()
+            .WithWorkingDirectory(newSolutionDir.FullName)
+            .Execute()
+            .Should().Pass();
+
+        new DotnetCommand(_testOutput, "sln", "add", Path.Combine("WebApp", "WebApp.csproj"))
+            .WithWorkingDirectory(newSolutionDir.FullName)
+            .Execute()
+            .Should().Pass();
+
+        new DotnetNewCommand(_testOutput, "classlib", "-n", "Library")
+            .WithVirtualHive()
+            .WithWorkingDirectory(newSolutionDir.FullName)
+            .Execute()
+            .Should().Pass();
+
+        new DotnetCommand(_testOutput, "sln", "add", Path.Combine("Library", "Library.csproj"))
+            .WithWorkingDirectory(newSolutionDir.FullName)
+            .Execute()
+            .Should().Pass();
+
+        // Set TFMs for Library - use current toolset + NS2.0 for compatibility
+        // also set IsPublishable to false
+        using (FileStream stream = File.Open(Path.Join(newSolutionDir.FullName, "Library", "Library.csproj"), FileMode.Open, FileAccess.ReadWrite))
+        {
+            XDocument document = await XDocument.LoadAsync(stream, LoadOptions.None, CancellationToken.None);
+            var tfmNode =
+                document
+                .Descendants()
+                .First(e => e.Name.LocalName == "TargetFramework");
+            var propertyGroupNode = tfmNode.Parent!;
+            tfmNode.Remove();
+            propertyGroupNode.Add(new XElement("TargetFrameworks", $"{ToolsetInfo.CurrentTargetFramework};netstandard2.0"));
+            propertyGroupNode.Add(new XElement("IsPublishable", "false"));
+            stream.SetLength(0);
+            await document.SaveAsync(stream, SaveOptions.None, CancellationToken.None);
+        }
+
+        // Publish
+        CommandResult commandResult = new DotnetCommand(_testOutput, "publish", "/t:PublishContainer", "-bl")
+            .WithWorkingDirectory(newSolutionDir.FullName)
+            .Execute();
+
+        commandResult.Should().Pass();
+        commandResult.Should().HaveStdOutContaining("Pushed image 'webapp:latest'");
+    }
+
     [DockerAvailableTheory()]
     [InlineData("webapi", false)]
     [InlineData("webapi", true)]
@@ -1012,7 +1088,7 @@ public void EndToEndMultiArch_RemoteRegistry()
             .And.HaveStdOutContaining($"Pushed image '{imageX64}' to registry '{registry}'.")
             .And.HaveStdOutContaining($"Pushed image '{imageArm64}' to registry '{registry}'.")
             .And.HaveStdOutContaining($"Pushed image index '{imageIndex}' to registry '{registry}'.");
-        
+
         // Check that the containers can be run
         // First pull the image from the registry for each platform
         ContainerCli.PullCommand(
@@ -1029,7 +1105,7 @@ public void EndToEndMultiArch_RemoteRegistry()
             imageFromRegistry)
             .Execute()
             .Should().Pass();
-        
+
         // Run the containers
         ContainerCli.RunCommand(
             _testOutput,