Disable table formatting by default

This changes the behavior of the formatter to not define
DOTNET_FORMATTER by default.  It can be opted into by using the /tables
option.

The reason for this change is to avoid a bug in Roslyn around changing
and resetting the parser options.  When hit Roslyn will end up changing
all files in the solution to have a different encoding / line ending.

I haven't yet tracked down this bug but short term making this opt-in
behavior so users aren't adversely affected by it.

Author: jaredpar

src/CodeFormatter/Program.cs

@@ -24,13 +24,14 @@ private static int Main(string[] args)
         {
             if (args.Length < 1)
             {
-                Console.WriteLine("CodeFormatter <project or solution> [<rule types>] [/file:<filename>] [/nocopyright] [/c:<config1,config2> [/copyright:file]");
+                Console.WriteLine("CodeFormatter <project or solution> [<rule types>] [/file:<filename>] [/nocopyright] [/tables] [/c:<config1,config2> [/copyright:file]");
                 Console.WriteLine("    <rule types> - Rule types to use in addition to the default ones.");
                 Console.WriteLine("                   Use ConvertTests to convert MSTest tests to xUnit.");
                 Console.WriteLine("    <filename>   - Only apply changes to files with specified name.");
                 Console.WriteLine("    <configs>    - Additional preprocessor configurations the formatter");
                 Console.WriteLine("                   should run under.");
                 Console.WriteLine("    <copyright>  - Specifies file containing copyright header.");
+                Console.WriteLine("    <tables>     - Let tables opt out of formatting by defining DOTNET_FORMATTER");
                 return -1;
             }
 
@@ -45,6 +46,7 @@ private static int Main(string[] args)
             var ruleTypeBuilder = ImmutableArray.CreateBuilder<string>();
             var configBuilder = ImmutableArray.CreateBuilder<string[]>();
             var copyrightHeader = FormattingConstants.DefaultCopyrightHeader;
+            var allowTables = false;
             var comparer = StringComparer.OrdinalIgnoreCase;
 
             for (int i = 1; i < args.Length; i++)
@@ -80,6 +82,10 @@ private static int Main(string[] args)
                 {
                     copyrightHeader = ImmutableArray<string>.Empty;
                 }
+                else if (comparer.Equals(arg, "/tables"))
+                {
+                    allowTables = true;
+                }
                 else
                 {
                     ruleTypeBuilder.Add(arg);
@@ -99,6 +105,7 @@ private static int Main(string[] args)
                     fileNamesBuilder.ToImmutableArray(),
                     configBuilder.ToImmutableArray(),
                     copyrightHeader,
+                    allowTables,
                     ct).Wait(ct);
                 Console.WriteLine("Completed formatting.");
                 return 0;
@@ -124,13 +131,15 @@ private static async Task RunAsync(
             ImmutableArray<string> fileNames, 
             ImmutableArray<string[]> preprocessorConfigurations, 
             ImmutableArray<string> copyrightHeader,
+            bool allowTables,
             CancellationToken cancellationToken)
         {
             var workspace = MSBuildWorkspace.Create();
             var engine = FormattingEngine.Create(ruleTypes);
             engine.PreprocessorConfigurations = preprocessorConfigurations;
             engine.FileNames = fileNames;
             engine.CopyrightHeader = copyrightHeader;
+            engine.AllowTables = allowTables;
 
             string extension = Path.GetExtension(projectOrSolutionPath);
             if (StringComparer.OrdinalIgnoreCase.Equals(extension, ".sln"))

src/Microsoft.DotNet.CodeFormatting/FormattingEngineImplementation.cs

@@ -33,6 +33,7 @@ internal sealed class FormattingEngineImplementation : IFormattingEngine
         private readonly IEnumerable<ILocalSemanticFormattingRule> _localSemanticRules;
         private readonly IEnumerable<IGlobalSemanticFormattingRule> _globalSemanticRules;
         private readonly Stopwatch _watch = new Stopwatch();
+        private bool _allowTables;
 
         public ImmutableArray<string> CopyrightHeader
         {
@@ -58,6 +59,12 @@ public IFormatLogger FormatLogger
             set { _options.FormatLogger = value; }
         }
 
+        public bool AllowTables
+        {
+            get { return _allowTables; }
+            set { _allowTables = value; }
+        }
+
         [ImportingConstructor]
         internal FormattingEngineImplementation(
             Options options,
@@ -142,11 +149,21 @@ private Solution RemoveTablePreprocessorSymbol(Solution newSolution, Solution ol
         internal async Task<Solution> FormatCoreAsync(Solution originalSolution, IReadOnlyList<DocumentId> documentIds, CancellationToken cancellationToken)
         {
             var solution = originalSolution;
-            solution = AddTablePreprocessorSymbol(originalSolution);
+
+            if (_allowTables)
+            {
+                solution = AddTablePreprocessorSymbol(originalSolution);
+            }
+
             solution = await RunSyntaxPass(solution, documentIds, cancellationToken);
             solution = await RunLocalSemanticPass(solution, documentIds, cancellationToken);
             solution = await RunGlobalSemanticPass(solution, documentIds, cancellationToken);
-            solution = RemoveTablePreprocessorSymbol(solution, originalSolution);
+
+            if (_allowTables)
+            {
+                solution = RemoveTablePreprocessorSymbol(solution, originalSolution);
+            }
+
             return solution;
         }
 

src/Microsoft.DotNet.CodeFormatting/IFormattingEngine.cs

@@ -15,6 +15,7 @@ public interface IFormattingEngine
         ImmutableArray<string> CopyrightHeader { get; set; }
         ImmutableArray<string[]> PreprocessorConfigurations { get; set; }
         ImmutableArray<string> FileNames { get; set; }
+        bool AllowTables { get; set; }
         Task FormatSolutionAsync(Solution solution, CancellationToken cancellationToken);
         Task FormatProjectAsync(Project porject, CancellationToken cancellationToken);
     }