Fix invalid target framework error for Solution restore

src/NuGet.Core/NuGet.Build.Tasks.Console/MSBuildStaticGraphRestore.cs

@@ -525,6 +525,11 @@ internal static string[] GetTargetFrameworkStrings(IMSBuildProject project)
             if (string.IsNullOrEmpty(targetFrameworks))
             {
                 targetFrameworks = project.GetProperty("TargetFramework");
+                if (targetFrameworks.Contains(';'))
+                {
+                    var error = RestoreLogMessage.CreateError(NuGetLogCode.NU1001, string.Format(CultureInfo.CurrentCulture, Strings.Error_TargetFrameworkWithSemicolon, targetFrameworks));
+                    throw new RestoreCommandException(error);
+                }
             }
             var projectFrameworkStrings = MSBuildStringUtility.Split(targetFrameworks);
             return projectFrameworkStrings;

src/NuGet.Core/NuGet.Build.Tasks/Strings.resx

@@ -229,4 +229,8 @@
     <value>An error occurred starting static graph-based restore. {0}. Please file an issue at https://github.com/NuGet/Home</value>
     <comment>0 - The exception message</comment>
   </data>
+  <data name="Error_TargetFrameworkWithSemicolon" xml:space="preserve">
+    <value>The TargetFramework value '{0}' is not valid. To multi-target, use the 'TargetFrameworks' property instead.</value>
+    <comment>0 - Is a string with a list of target frameworks separated by a semi colon</comment>
+  </data>
 </root>

src/NuGet.Core/NuGet.Commands/RestoreCommand/Utility/MSBuildRestoreUtility.cs

@@ -458,6 +458,12 @@ private static IEnumerable<TargetFrameworkInformation> GetTargetFrameworkInforma
             foreach (var item in GetItemByType(items, "TargetFrameworkInformation"))
             {
                 var frameworkString = item.GetProperty("TargetFramework");
+                if (frameworkString.Contains(';'))
+                {
+                    var error = RestoreLogMessage.CreateError(NuGetLogCode.NU1001, string.Format(CultureInfo.CurrentCulture, Strings.Error_TargetFrameworkWithSemicolon, frameworkString));
+                    throw new RestoreCommandException(error);
+                }
+
                 var targetFrameworkMoniker = item.GetProperty("TargetFrameworkMoniker");
                 var targetPlatforMoniker = item.GetProperty("TargetPlatformMoniker");
                 var targetPlatformMinVersion = item.GetProperty("TargetPlatformMinVersion");

src/NuGet.Core/NuGet.Commands/Strings.resx

@@ -1127,4 +1127,8 @@ NuGet requires HTTPS sources. Refer to https://aka.ms/nuget-https-everywhere for
     <value>Audit source '{0}' did not provide any vulnerability data.</value>
     <comment>{0} is the source name</comment>
   </data>
+  <data name="Error_TargetFrameworkWithSemicolon" xml:space="preserve">
+    <value>The TargetFramework value '{0}' is not valid. To multi-target, use the 'TargetFrameworks' property instead.</value>
+    <comment>0 - Is a string with a list of target frameworks separated by a semi colon</comment>
+  </data>
 </root>

test/NuGet.Core.Tests/NuGet.Build.Tasks.Console.Test/MSBuildStaticGraphRestoreTests.cs

@@ -101,6 +101,19 @@ public void GetOriginalTargetFrameworks_WhenTargetFramworksSpecified_HasCorrectT
             actual.Should().BeEquivalentTo(expected);
         }
 
+        [Theory]
+        [InlineData("net40;net45")]
+        [InlineData("net40;net45 ; netstandard2.0 ")]
+        public void GetOriginalTargetFramework_WhenTargetFramworkSpecified_HasCorrectTargetFramework(string targetFrameworks)
+        {
+            var project = new MockMSBuildProject(new Dictionary<string, string>
+            {
+                ["TargetFramework"] = targetFrameworks
+            });
+
+            Assert.Throws<RestoreCommandException>(() => MSBuildStaticGraphRestore.GetTargetFrameworkStrings(project));
+        }
+
         [Fact]
         public void GetPackageDownloads_WhenDuplicatesExist_DuplicatesIgnored()
         {

test/NuGet.Core.Tests/NuGet.Commands.Test/MSBuildRestoreUtilityTests.cs

@@ -3399,6 +3399,36 @@ public void MSBuildRestoreUtility_AddPackageDownloads_InvalidVersionRange(string
             var exception = Assert.Throws<ArgumentException>(() => MSBuildRestoreUtility.AddPackageDownloads(spec, msbuildItems));
         }
 
+        [Fact]
+        public void MSBuildRestoreUtility_GetPackageSpec_InvalidTargetFramework()
+        {
+            // Arrange
+            var targetFramework = "netstandard2.0;net7.0";
+            var items = new[] {
+                 CreateItems(new Dictionary<string, string>()
+                {
+                    { "Type", "ProjectSpec" },
+                    { "ProjectName", "a" },
+                    { "ProjectStyle", "PackageReference" },
+                    { "ProjectUniqueName", "a" },
+                }),
+            CreateItems(new Dictionary<string, string>()
+                {
+                    { "Type", "TargetFrameworkInformation" },
+                    { "AssetTargetFallback", "" },
+                    { "PackageTargetFallback", "" },
+                    { "ProjectUniqueName", "a" },
+                    { "TargetFramework", targetFramework },
+                    { "TargetPlatformIdentifier", "" },
+                    { "TargetPlatformMoniker", "" },
+                    { "TargetPlatformVersion", "" },
+                })
+            };
+
+            // Act & Assert
+            var exception = Assert.Throws<RestoreCommandException>(() => MSBuildRestoreUtility.GetPackageSpec(items));
+        }
+
         [Fact]
         public void MSBuildRestoreUtility_AddPackageDownloads_NoVersion_ThrowsException()
         {