Use async read for process output

src/Interactive/EditorFeatures/Core/Extensibility/Interactive/NuGetPackageResolverImpl.cs

@@ -82,7 +82,6 @@ internal override ImmutableArray<string> ResolveNuGetPackage(string reference)
         internal static bool ParsePackageReference(string reference, out string name, out string version)
         {
             var parts = reference.Split('/');
-            int n = reference.Length;
             if ((parts.Length == 2) &&
                 (parts[0].Length > 0) &&
                 (parts[1].Length > 0))
@@ -187,17 +186,9 @@ private void NuGetRestore(string projectJsonPath)
         private static void NuGetRestore(ProcessStartInfo startInfo)
         {
             var process = Process.Start(startInfo);
-            string line;
-            var reader = process.StandardOutput;
-            while ((line = reader.ReadLine()) != null)
-            {
-                // Should echo output to InteractiveWindow.
-            }
-            reader = process.StandardError;
-            while ((line = reader.ReadLine()) != null)
-            {
-                // Should echo errors to InteractiveWindow.
-            }
+            // Should echo output and errors to InteractiveWindow.
+            process.StandardOutput.ReadToEndAsync();
+            process.StandardError.ReadToEndAsync();
             process.WaitForExit();
         }
     }

src/Interactive/HostTest/NuGetPackageResolverTests.cs

@@ -4,7 +4,7 @@
 using Microsoft.CodeAnalysis.Test.Utilities;
 using Roslyn.Test.Utilities;
 using Roslyn.Utilities;
-using System.Collections.Immutable;
+using System;
 using System.IO;
 using System.Text;
 using Xunit;
@@ -89,6 +89,27 @@ public void ResolveReference()
             }
         }
 
+        [ConditionalFact(typeof(WindowsOnly))]
+        public void HandledException()
+        {
+            using (var directory = new DisposableDirectory(Temp))
+            {
+                var resolver = new NuGetPackageResolverImpl(directory.Path, startInfo => { throw new IOException(); });
+                var actualPaths = resolver.ResolveNuGetPackage("A.B.C/1.2");
+                Assert.True(actualPaths.IsDefault);
+            }
+        }
+
+        [ConditionalFact(typeof(WindowsOnly))]
+        public void UnhandledException()
+        {
+            using (var directory = new DisposableDirectory(Temp))
+            {
+                var resolver = new NuGetPackageResolverImpl(directory.Path, startInfo => { throw new InvalidOperationException(); });
+                Assert.Throws<InvalidOperationException>(() => resolver.ResolveNuGetPackage("A.B.C/1.2"));
+            }
+        }
+
         [ConditionalFact(typeof(WindowsOnly))]
         public void ParsePackageNameAndVersion()
         {