escape semicolons when forwarding RestoreSources to MSBuild

src/dotnet/commands/dotnet-msbuild/MSBuildForwardingApp.cs

@@ -41,10 +41,12 @@ namespace Microsoft.DotNet.Tools.MSBuild
                 {
                     Type loggerType = typeof(MSBuildLogger);
 
-                    argsToForward = argsToForward.Concat(new[]
+                    argsToForward = argsToForward
-                    {
+                        .Select(Escape)
-                        $"/Logger:{loggerType.FullName},{loggerType.GetTypeInfo().Assembly.Location}"
+                        .Concat(new[]
-                    });
+                        {
+                            $"/Logger:{loggerType.FullName},{loggerType.GetTypeInfo().Assembly.Location}"
+                        });
                 }
                 catch (Exception)
                 {
@@ -77,6 +79,11 @@ namespace Microsoft.DotNet.Tools.MSBuild
             return app.Option("-v|--verbosity", LocalizableStrings.VerbosityOptionDescription, CommandOptionType.SingleValue);
         }
 
+        private static string Escape(string arg) =>
+             (arg.StartsWith("/p:RestoreSources=", StringComparison.OrdinalIgnoreCase)) ?
+                arg.Replace(";", "%3B") : // <-- this is a workaround for https://github.com/Microsoft/msbuild/issues/1622
+                arg;
+
         private static string GetMSBuildExePath()
         {
             return Path.Combine(

test/dotnet-msbuild.Tests/GivenDotnetMSBuildBuildsProjects.cs

@@ -5,6 +5,7 @@ using System;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
+using System.Runtime.InteropServices;
 using FluentAssertions;
 using Microsoft.DotNet.Configurer;
 using Microsoft.DotNet.Tools.MSBuild;
@@ -76,6 +77,30 @@ namespace Microsoft.DotNet.Cli.MSBuild.Tests
             }
         }
 
+        [Fact]
+        public void WhenRestoreSourcesStartsWithUnixPathThenHttpsSourceIsParsedCorrectly()
+        {
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                return;
+            }
+
+            // this is a workaround for https://github.com/Microsoft/msbuild/issues/1622
+            var testInstance = TestAssets.Get("MSBuildTestApp")
+                                        .CreateInstance()
+                                        .WithSourceFiles()
+                                        .WithRestoreFiles();
+
+            var root = testInstance.Root;
+            var somePathThatExists = "/usr/local/bin";
+
+            var result = new DotnetCommand()
+                .WithWorkingDirectory(root)
+                .Execute($"msbuild /p:RestoreSources={somePathThatExists};https://api.nuget.org/v3/index.json /t:restore MSBuildTestApp.csproj");
+         
+            result.Should().Pass();
+        }
+
         [Fact]
         public void WhenDotnetRunHelpIsInvokedAppArgumentsTextIsIncludedInOutput()
         {
@@ -85,7 +110,7 @@ namespace Microsoft.DotNet.Cli.MSBuild.Tests
             var result = new TestCommand("dotnet")
                 .WithWorkingDirectory(projectDirectory.Path)
                 .ExecuteWithCapturedOutput("run --help");
-            
+
             result.ExitCode.Should().Be(0);
             result.StdOut.Should().Contain(AppArgumentsText);
         }