Fix unstable MSBuild compilation cache (#3)

T4.Build/Program.cs

@@ -1,5 +1,6 @@
 using System;
 using System.CodeDom.Compiler;
+using System.Collections;
 using System.Collections.Concurrent;
 using System.CommandLine;
 using System.CommandLine.Invocation;
@@ -44,6 +45,7 @@ static int Transform(FileInfo[] templates, int lockTimeout, bool skipUpToDate, b
  {
  using (var locker = new Lock($"Global\\T4.Build.transform.{ComputeHash(templates)}.lock", lockTimeout))
  {
+ var outputQueue = new ConcurrentQueue<String>();
  var errorQueue = new ConcurrentQueue<CompilerErrorCollection>();
  var didSomeWork = false;
  var stopwatch = new Stopwatch();
@@ -63,7 +65,7 @@ static int Transform(FileInfo[] templates, int lockTimeout, bool skipUpToDate, b
  if (generator.Errors.HasErrors)
  errorQueue.Enqueue(generator.Errors);
  else
- Console.WriteLine(generator.OutputFile);
+ outputQueue.Enqueue(generator.OutputFile);
  }
  catch (Exception e)
  {
@@ -72,6 +74,12 @@ static int Transform(FileInfo[] templates, int lockTimeout, bool skipUpToDate, b
  });
  stopwatch.Stop();
 
+ // Sort the generated file names so that the MSBuild compilation cache hash remains stable
+ var outputs = outputQueue.ToArray();
+ Array.Sort(outputs, new CaseInsensitiveComparer());
+ foreach (var output in outputs)
+ Console.WriteLine(output);
+
  if (didSomeWork && errorQueue.IsEmpty)
  Console.Error.WriteLine($"Templates transformed for {Path.GetFileName(Directory.GetCurrentDirectory())} (in {stopwatch.ElapsedMilliseconds / 1000.0} sec).");