Fix up bugs in parsing special chracters in EditorConfig (#54511)

* Fix up bugs in parsing special chracters in EditorConfig

* Address feedback from peer review

* Update tests, clean  lexer logic, update method mdoifiers

* Fix method modifier

src/Compilers/Core/CodeAnalysisTest/Analyzers/AnalyzerConfigTests.cs

@@ -93,6 +93,28 @@ public void ConfigWithEscapedValues()
             );
         }
 
+        [Fact]
+        [WorkItem(52469, "https://github.com/dotnet/roslyn/issues/52469")]
+        public void CanGetSectionsWithSpecialCharacters()
+        {
+            var config = ParseConfigFile(@"is_global = true
+
+[/home/foo/src/\{releaseid\}.cs]
+build_metadata.Compile.ToRetrieve = abc123
+
+[/home/foo/src/Pages/\#foo/HomePage.cs]
+build_metadata.Compile.ToRetrieve = def456
+");
+
+            var set = AnalyzerConfigSet.Create(ImmutableArray.Create(config));
+
+            var sectionOptions = set.GetOptionsForSourcePath("/home/foo/src/{releaseid}.cs");
+            Assert.Equal("abc123", sectionOptions.AnalyzerOptions["build_metadata.compile.toretrieve"]);
+
+            sectionOptions = set.GetOptionsForSourcePath("/home/foo/src/Pages/#foo/HomePage.cs");
+            Assert.Equal("def456", sectionOptions.AnalyzerOptions["build_metadata.compile.toretrieve"]);
+        }
+
         [ConditionalFact(typeof(WindowsOnly))]
         public void WindowsPath()
         {

src/Compilers/Core/MSBuildTask/GenerateMSBuildEditorConfig.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.IO;
 using System.Linq;
 using System.Text;
 using Microsoft.Build.Framework;
@@ -38,6 +39,10 @@ namespace Microsoft.CodeAnalysis.BuildTasks
     /// </remarks>
     public sealed class GenerateMSBuildEditorConfig : Task
     {
+        /// <remarks>
+        /// Although this task does its own writing to disk, this
+        /// output parameter is here for testing purposes.
+        /// </remarks>
         [Output]
         public string ConfigFileContents { get; set; }
 
@@ -47,11 +52,14 @@ public sealed class GenerateMSBuildEditorConfig : Task
         [Required]
         public ITaskItem[] PropertyItems { get; set; }
 
+        public ITaskItem FileName { get; set; }
+
         public GenerateMSBuildEditorConfig()
         {
             ConfigFileContents = string.Empty;
             MetadataItems = Array.Empty<ITaskItem>();
             PropertyItems = Array.Empty<ITaskItem>();
+            FileName = new TaskItem();
         }
 
         public override bool Execute()
@@ -98,7 +106,31 @@ public override bool Execute()
             }
 
             ConfigFileContents = builder.ToString();
-            return true;
+            return string.IsNullOrEmpty(FileName.ItemSpec) ? true : WriteMSBuildEditorConfig();
+        }
+
+        internal bool WriteMSBuildEditorConfig()
+        {
+            try
+            {
+                var targetFileName = FileName.ItemSpec;
+                if (File.Exists(targetFileName))
+                {
+                    string existingContents = File.ReadAllText(targetFileName);
+                    if (existingContents.Equals(ConfigFileContents))
+                    {
+                        return true;
+                    }
+                }
+                var encoding = new UTF8Encoding(encoderShouldEmitUTF8Identifier: false, throwOnInvalidBytes: true);
+                File.WriteAllText(targetFileName, ConfigFileContents, encoding);
+                return true;
+            }
+            catch (IOException ex)
+            {
+                Log.LogErrorFromException(ex);
+                return false;
+            }
         }
 
         /// <remarks>

src/Compilers/Core/MSBuildTask/Microsoft.Managed.Core.targets

@@ -186,14 +186,10 @@
     <!-- Transform the collected properties and items into an editor config file -->
     <GenerateMSBuildEditorConfig
       PropertyItems="@(_GeneratedEditorConfigProperty)"
-      MetadataItems="@(_GeneratedEditorConfigMetadata)">
-
-      <Output TaskParameter="ConfigFileContents"
-          PropertyName="_GeneratedEditorConfigFileContent" />
+      MetadataItems="@(_GeneratedEditorConfigMetadata)"
+      FileName="$(GeneratedMSBuildEditorConfigFile)">
     </GenerateMSBuildEditorConfig>
 
-    <!-- Write the output to the generated file, if it's changed -->
-    <WriteLinesToFile Lines="$(_GeneratedEditorConfigFileContent)" File="$(GeneratedMSBuildEditorConfigFile)" Overwrite="True" WriteOnlyWhenDifferent="True" />
   </Target>
 
   <!--

src/Compilers/Core/MSBuildTaskTests/GenerateMSBuildEditorConfigTests.cs

@@ -7,10 +7,12 @@
 using System.IO;
 using System.Linq;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 using System.Text;
 using System.Threading.Tasks;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
+using Microsoft.CodeAnalysis.Test.Utilities;
 using Roslyn.Test.Utilities;
 using Xunit;
 
@@ -351,5 +353,30 @@ public void ItemMetadataPathIsAdjustedOnWindows()
 build_metadata.Compile.ToRetrieve = abc123
 ", result);
         }
+
+        [Fact]
+        public void ConfigFileCanBeWrittenToDisk()
+        {
+            ITaskItem property1 = MSBuildUtil.CreateTaskItem("Property1", new Dictionary<string, string> { { "Value", "abc123" } });
+            ITaskItem property2 = MSBuildUtil.CreateTaskItem("Property2", new Dictionary<string, string> { { "Value", "def456" } });
+
+            var fileName = Path.Combine(TempRoot.Root, "ConfigFileCanBeWrittenToDisk.GenerateMSBuildEditorConfig.editorconfig");
+
+            GenerateMSBuildEditorConfig configTask = new GenerateMSBuildEditorConfig()
+            {
+                PropertyItems = new[] { property1, property2 },
+                FileName = new TaskItem(fileName)
+            };
+            configTask.Execute();
+
+            var expectedContents = @"is_global = true
+build_property.Property1 = abc123
+build_property.Property2 = def456
+";
+
+            Assert.True(File.Exists(fileName));
+            Assert.True(configTask.WriteMSBuildEditorConfig());
+            Assert.Equal(expectedContents, File.ReadAllText(fileName));
+        }
     }
 }

src/Compilers/Core/Portable/CommandLine/AnalyzerConfig.SectionNameMatching.cs

@@ -114,6 +114,22 @@ public bool IsMatch(string s)
                 numberRangePairs.ToImmutableAndFree());
         }
 
+        internal static bool TryUnescapeSectionName(string sectionName, out string? escapedSectionName)
+        {
+            var sb = new StringBuilder();
+            SectionNameLexer lexer = new SectionNameLexer(sectionName);
+            while (!lexer.IsDone)
+            {
+                var tokenKind = lexer.Lex();
+                if (tokenKind == TokenKind.SimpleCharacter)
+                {
+                    sb.Append(lexer.EatCurrentCharacter());
+                }
+            }
+            escapedSectionName = sb.ToString();
+            return true;
+        }
+
         /// <summary>
         /// Test if a section name is an absolute path with no special chars
         /// </summary>

src/Compilers/Core/Portable/CommandLine/AnalyzerConfigSet.cs

@@ -199,7 +199,8 @@ public AnalyzerConfigOptionsResult GetOptionsForSourcePath(string sourcePath)
             // If we have a global config, add any sections that match the full path 
             foreach (var section in _globalConfig.NamedSections)
             {
-                if (normalizedPath.Equals(section.Name, Section.NameComparer))
+                var escapedSectionName = TryUnescapeSectionName(section.Name, out var sectionName);
+                if (escapedSectionName && normalizedPath.Equals(sectionName, Section.NameComparer))
                 {
                     sectionKey.Add(section);
                 }