Adding a Minimum VS Defined SDK version to the resolver. If it set to 1.0.4 if the minimum SDK version file is not found.

Author: livarcocc

src/Microsoft.DotNet.MSBuildSdkResolver/Interop.NETStandard.cs

@@ -2,10 +2,10 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 // NOTE: Currently, only the NET46 build ships (with Visual Studio/desktop msbuild), 
-// but the netstandard1.3 adaptation here acts a proof-of-concept for cross-platform 
+// but the netstandard1.5 adaptation here acts a proof-of-concept for cross-platform 
 // portability of the underlying hostfxr API and gives us build and test coverage 
 // on non-Windows machines.
-#if NETSTANDARD1_3
+#if NETSTANDARD1_5
 
 using System.Runtime.InteropServices;
 using System.Text;
@@ -34,4 +34,4 @@ private static int hostfxr_resolve_sdk(string exe_dir, string working_dir, [Out]
     }
 }
 
-#endif // NETSTANDARD1_3
+#endif // NETSTANDARD1_5

src/Microsoft.DotNet.MSBuildSdkResolver/MSBuildSdkResolver.cs

@@ -6,6 +6,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Reflection;
 
 namespace Microsoft.DotNet.MSBuildSdkResolver
 {
@@ -64,6 +65,7 @@ public override SdkResult Resolve(SdkReference sdkReference, SdkResolverContext
                             + " the version specified in global.json."
                         });
                 }
+
                 string minimumMSBuildVersionString = GetMinimumMSBuildVersion(netcoreSdkDir);
                 var minimumMSBuildVersion = Version.Parse(minimumMSBuildVersionString);
                 if (context.MSBuildVersion < minimumMSBuildVersion)
@@ -77,6 +79,18 @@ public override SdkResult Resolve(SdkReference sdkReference, SdkResolverContext
                             + " version currently available."
                         });
                 }
+
+                string minimumVSDefinedSDKVersion = GetMinimumVSDefinedSDKVersion();                
+                if (IsNetCoreSDKSmallerThanTheMinimumVersion(netcoreSdkVersion, minimumVSDefinedSDKVersion))
+                {
+                    return factory.IndicateFailure(
+                        new[]
+                        {
+                            $"Version {netcoreSdkVersion} of the .NET Core SDK is smaller than the minimum version"
+                            + $" {minimumVSDefinedSDKVersion} required by Visual Studio. Check that a recent enough"
+                            + " .NET Core SDK is installed or increase the version specified in global.json."
+                        });
+                }
             }
 
             string msbuildSdkDir = Path.Combine(msbuildSdksDir, sdkReference.Name, "Sdk");
@@ -107,6 +121,22 @@ private static string GetMinimumMSBuildVersion(string netcoreSdkDir)
             return File.ReadLines(minimumVersionFilePath).First().Trim();
         }
 
+        private static string GetMinimumVSDefinedSDKVersion()
+        {
+            string dotnetMSBuildSdkResolverDirectory =
+                Path.GetDirectoryName(typeof(DotNetMSBuildSdkResolver).GetTypeInfo().Assembly.Location);
+            string minimumVSDefinedSdkVersionFilePath =
+                Path.Combine(dotnetMSBuildSdkResolverDirectory, "minimumVSDefinedSDKVersion");
+
+            if (!File.Exists(minimumVSDefinedSdkVersionFilePath))
+            {
+                // smallest version that is required by VS 15.3.
+                return "1.0.4";
+            }
+
+            return File.ReadLines(minimumVSDefinedSdkVersionFilePath).First().Trim();
+        }
+
         private bool IsNetCoreSDKSmallerThanTheMinimumVersion(string netcoreSdkVersion, string minimumVersion)
         {
             FXVersion netCoreSdkFXVersion;

src/Microsoft.DotNet.MSBuildSdkResolver/Microsoft.DotNet.MSBuildSdkResolver.csproj

@@ -3,8 +3,8 @@
 
   <PropertyGroup>
     <Version>$(SdkVersion)</Version>
-    <TargetFrameworks>netstandard1.3;net46</TargetFrameworks>
-    <TargetFrameworks Condition="'$(OS)' != 'Windows_NT'">netstandard1.3</TargetFrameworks>
+    <TargetFrameworks>netstandard1.5;net46</TargetFrameworks>
+    <TargetFrameworks Condition="'$(OS)' != 'Windows_NT'">netstandard1.5</TargetFrameworks>
     <PlatformTarget>AnyCPU</PlatformTarget>
     <RuntimeIdentifiers>win-x86;win-x64</RuntimeIdentifiers>
     <WarningsAsErrors>true</WarningsAsErrors>
@@ -20,7 +20,7 @@
     <PackageReference Include="Microsoft.NETCore.DotNetHostResolver" Version="$(CLI_SharedFrameworkVersion)" PrivateAssets="All" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard1.3'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard1.5'">
     <PackageReference Include="NETStandard.Library" Version="1.6.0" />
   </ItemGroup>
 

test/Microsoft.DotNet.MSBuildSdkResolver.Tests/GivenAnMSBuildSdkResolver.cs

@@ -13,6 +13,8 @@
 using Xunit.Abstractions;
 using System;
 
+[assembly: CollectionBehavior(DisableTestParallelization = true)]
+
 namespace Microsoft.DotNet.Cli.Utils.Tests
 {
     public class GivenAnMSBuildSdkResolver : TestBase
@@ -106,11 +108,59 @@ public void ItReturnsNullWhenTheSDKRequiresAHigherVersionOfMSBuildThanTheOneAvai
         }
 
         [Fact]
-        public void ItReturnsTheVersionIfItIsEqualToTheMinVersion()
+        public void ItReturnsNullWhenTheDefaultVSRequiredSDKVersionIsHigherThanTheSDKVersionAvailable()
+        {
+            var environment = new TestEnvironment();
+            var expected =
+                environment.CreateSdkDirectory(ProgramFiles.X64, "Some.Test.Sdk", "1.0.1");
+            environment.CreateMuxerAndAddToPath(ProgramFiles.X64);
+
+            var resolver = environment.CreateResolver();
+            var result = (MockResult)resolver.Resolve(
+                new SdkReference("Some.Test.Sdk", null, "1.0.0"),
+                new MockContext { ProjectFilePath = environment.TestDirectory.FullName },
+                new MockFactory());
+
+            result.Success.Should().BeFalse();
+            result.Path.Should().BeNull();
+            result.Version.Should().BeNull();
+            result.Warnings.Should().BeNullOrEmpty();
+            result.Errors.Should().Contain($"Version 1.0.1 of the .NET Core SDK is smaller than the minimum version"
+                            + " 1.0.4 required by Visual Studio. Check that a recent enough"
+                            + " .NET Core SDK is installed or increase the version specified in global.json.");
+        }
+
+        [Fact]
+        public void ItReturnsNullWhenTheTheVSRequiredSDKVersionIsHigherThanTheSDKVersionAvailable()
+        {
+            var environment = new TestEnvironment();
+            var expected =
+                environment.CreateSdkDirectory(ProgramFiles.X64, "Some.Test.Sdk", "1.0.1");
+            environment.CreateMuxerAndAddToPath(ProgramFiles.X64);
+            environment.CreateMinimumVSDefinedSDKVersionFile("2.0.0");
+
+            var resolver = environment.CreateResolver();
+            var result = (MockResult)resolver.Resolve(
+                new SdkReference("Some.Test.Sdk", null, "1.0.0"),
+                new MockContext { ProjectFilePath = environment.TestDirectory.FullName },
+                new MockFactory());
+
+            result.Success.Should().BeFalse();
+            result.Path.Should().BeNull();
+            result.Version.Should().BeNull();
+            result.Warnings.Should().BeNullOrEmpty();
+            result.Errors.Should().Contain($"Version 1.0.1 of the .NET Core SDK is smaller than the minimum version"
+                            + " 2.0.0 required by Visual Studio. Check that a recent enough"
+                            + " .NET Core SDK is installed or increase the version specified in global.json.");
+        }
+
+        [Fact]
+        public void ItReturnsTheVersionIfItIsEqualToTheMinVersionAndTheVSDefinedMinVersion()
         {
             var environment = new TestEnvironment();
             var expected = environment.CreateSdkDirectory(ProgramFiles.X64, "Some.Test.Sdk", "99.99.99");
             environment.CreateMuxerAndAddToPath(ProgramFiles.X64);
+            environment.CreateMinimumVSDefinedSDKVersionFile("99.99.99");
 
             var resolver = environment.CreateResolver();
             var result = (MockResult)resolver.Resolve(
@@ -126,11 +176,12 @@ public void ItReturnsTheVersionIfItIsEqualToTheMinVersion()
         }
 
         [Fact]
-        public void ItReturnsTheVersionIfItIsHigherThanTheMinVersion()
+        public void ItReturnsTheVersionIfItIsHigherThanTheMinVersionAndTheVSDefinedMinVersion()
         {
             var environment = new TestEnvironment();
             var expected = environment.CreateSdkDirectory(ProgramFiles.X64, "Some.Test.Sdk", "999.99.99");
             environment.CreateMuxerAndAddToPath(ProgramFiles.X64);
+            environment.CreateMinimumVSDefinedSDKVersionFile("999.99.98");
 
             var resolver = environment.CreateResolver();
             var result = (MockResult)resolver.Resolve(
@@ -167,6 +218,8 @@ public TestEnvironment(string identifier = "", [CallerMemberName] string calling
                     identifier: identifier,
                     callingMethod: callingMethod);
 
+                DeleteMinimumVSDefinedSDKVersionFile();
+
                 PathEnvironmentVariable = string.Empty;
             }
 
@@ -248,6 +301,22 @@ public string GetEnvironmentVariable(string variable)
                         return null;
                 }
             }
+
+            public void CreateMinimumVSDefinedSDKVersionFile(string version)
+            {
+                File.WriteAllText(GetMinimumVSDefinedSDKVersionFilePath(), version);
+            }
+
+            private void DeleteMinimumVSDefinedSDKVersionFile()
+            {                
+                File.Delete(GetMinimumVSDefinedSDKVersionFilePath());
+            }
+
+            private string GetMinimumVSDefinedSDKVersionFilePath()
+            {
+                string baseDirectory = AppContext.BaseDirectory;
+                return Path.Combine(baseDirectory, "minimumVSDefinedSDKVersion");
+            }
         }
 
         private sealed class MockContext : SdkResolverContext