Improve indentation analysis (#1188)

.editorconfig

@@ -6,6 +6,9 @@ root = true
 # Code files
 [*.{cs,csx}]
 
+indent_style = space
+indent_size = 4
+
 dotnet_sort_system_directives_first = true
 
 csharp_style_namespace_declarations = file_scoped:suggestion

ChangeLog.md

@@ -39,6 +39,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix [RCS1208](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1208) ([#1153](https://github.com/JosefPihrt/Roslynator/pull/1153)).
 - Fix [RCS1043](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1043) ([#1176](https://github.com/JosefPihrt/Roslynator/pull/1176)).
 - [CLI] Fix exit code of `spellcheck` command ([#1177](https://github.com/JosefPihrt/Roslynator/pull/1177)).
+- Improve indentation analysis ([#1188](https://github.com/JosefPihrt/Roslynator/pull/1188)).
 
 ## [4.4.0] - 2023-08-01
 

src/Analyzers.xml

@@ -1446,6 +1446,7 @@ void M(
 Default maximal length is 140.</Summary>
     <ConfigOptions>
       <Option Key="max_line_length" />
+      <Option Key="tab_length" />
     </ConfigOptions>
   </Analyzer>
   <Analyzer>

src/Analyzers/CSharp/Analysis/RemoveEmptySyntaxAnalyzer.cs

@@ -66,7 +66,7 @@ private static void AnalyzeElseClause(SyntaxNodeAnalysisContext context)
         IfStatementSyntax topmostIf = elseClause.GetTopmostIf();
 
         if (topmostIf.Parent is IfStatementSyntax parentIf
-            && parentIf.Else != null)
+            && parentIf.Else is not null)
         {
             return;
         }

src/Analyzers/CSharp/Analysis/RemovePartialModifierFromTypeWithSinglePartAnalyzer.cs

@@ -14,7 +14,7 @@ public sealed class RemovePartialModifierFromTypeWithSinglePartAnalyzer : BaseDi
 {
     private static ImmutableArray<DiagnosticDescriptor> _supportedDiagnostics;
 
-    private static readonly MetadataName[] _metadataNames = new MetadataName[] {
+    private static readonly MetadataName[] _metadataNames = new[] {
         // ASP.NET Core
         MetadataName.Parse("Microsoft.AspNetCore.Components.ComponentBase"),
         // WPF

src/CodeFixes/CSharp/CodeFixes/AssignDefaultValueToOutParameterCodeFixProvider.cs

@@ -12,6 +12,7 @@
 using Microsoft.CodeAnalysis.CodeFixes;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
 using Roslynator.CodeFixes;
 using Roslynator.CSharp.Refactorings;
 using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
@@ -155,7 +156,9 @@ public override async Task RegisterCodeFixesAsync(CodeFixContext context)
 
         if (bodyOrExpressionBody is ArrowExpressionClauseSyntax expressionBody)
         {
-            newNode = ConvertExpressionBodyToBlockBodyRefactoring.Refactor(expressionBody, semanticModel, cancellationToken);
+            AnalyzerConfigOptions configOptions = document.GetConfigOptions(node.SyntaxTree);
+
+            newNode = ConvertExpressionBodyToBlockBodyRefactoring.Refactor(expressionBody, configOptions, semanticModel, cancellationToken);
 
             newNode = InsertStatements(newNode, expressionStatements);
         }

src/Common/CSharp/Extensions/CodeStyleExtensions.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Josef Pihrt and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Globalization;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Roslynator.Configuration;
 using Roslynator.CSharp.CodeStyle;
@@ -9,6 +10,42 @@ namespace Roslynator.CSharp;
 
 internal static class CodeStyleExtensions
 {
+    public static bool TryGetTabLength(this AnalyzerConfigOptions configOptions, out int tabLength)
+    {
+        if (configOptions.TryGetValue(ConfigOptionKeys.TabLength, out string tabLengthStr)
+            && int.TryParse(tabLengthStr, NumberStyles.None, CultureInfo.InvariantCulture, out tabLength))
+        {
+            return true;
+        }
+
+        tabLength = 0;
+        return false;
+    }
+
+    public static bool TryGetIndentSize(this AnalyzerConfigOptions configOptions, out int indentSize)
+    {
+        if (configOptions.TryGetValue("indent_size", out string indentSizeStr)
+            && int.TryParse(indentSizeStr, NumberStyles.None, CultureInfo.InvariantCulture, out indentSize))
+        {
+            return true;
+        }
+
+        indentSize = 0;
+        return false;
+    }
+
+    public static bool TryGetIndentStyle(this AnalyzerConfigOptions configOptions, out IndentStyle indentStyle)
+    {
+        if (configOptions.TryGetValue("indent_style", out string indentStyleStr)
+            && Enum.TryParse(indentStyleStr, ignoreCase: true, out indentStyle))
+        {
+            return true;
+        }
+
+        indentStyle = IndentStyle.Space;
+        return false;
+    }
+
     public static bool GetPrefixFieldIdentifierWithUnderscore(this AnalyzerConfigOptions configOptions)
     {
         if (configOptions.TryGetValueAsBool(ConfigOptions.PrefixFieldIdentifierWithUnderscore, out bool value))

src/CSharp/CSharp/IndentationAnalysis.cs → src/Common/CSharp/IndentationAnalysis.cs

@@ -5,62 +5,86 @@
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
 
 namespace Roslynator.CSharp;
 
 [DebuggerDisplay("{DebuggerDisplay,nq}")]
-internal readonly struct IndentationAnalysis
+internal sealed class IndentationAnalysis
 {
     private readonly int? _indentSize;
-    private readonly SyntaxTrivia? _singleIndentation;
+    private readonly SyntaxTrivia? _indentStep;
 
-    private IndentationAnalysis(SyntaxTrivia indentation, int? indentSize, SyntaxTrivia? singleIndentation)
+    private IndentationAnalysis(SyntaxTrivia indentation, IndentStyle? indentStyle, int? indentSize, SyntaxTrivia? indentStep)
     {
         Indentation = indentation;
+        IndentStyle = indentStyle;
         _indentSize = indentSize;
-        _singleIndentation = singleIndentation;
+        _indentStep = indentStep;
     }
 
     public SyntaxTrivia Indentation { get; }
 
-    public int IndentSize => _indentSize ?? _singleIndentation?.Span.Length ?? 0;
+    public IndentStyle? IndentStyle { get; }
 
-    public int IndentationLength => Indentation.Span.Length;
+    public int IndentSize => _indentSize ?? _indentStep?.Span.Length ?? 0;
 
-    public int IncreasedIndentationLength => (IndentSize > 0) ? Indentation.Span.Length + IndentSize : 0;
+    public int IndentationLength => Indentation.Span.Length;
 
-    public bool IsDefault
+    public int IncreasedIndentationLength
     {
         get
         {
-            return Indentation.IsKind(SyntaxKind.None)
-                && _indentSize is null
-                && _singleIndentation is null;
+            if (IndentSize > 0)
+            {
+                if (IndentStyle == Roslynator.IndentStyle.Tab)
+                    return IndentationLength + 1;
+
+                return IndentationLength + IndentSize;
+            }
+
+            if (_indentStep is not null)
+                return IndentationLength + 4;
+
+            return IndentationLength;
         }
     }
 
     [DebuggerBrowsable(DebuggerBrowsableState.Never)]
-    private string DebuggerDisplay => $"Length = {Indentation.Span.Length} {nameof(IndentSize)} = {IndentSize}";
+    private string DebuggerDisplay => $"Length = {IndentationLength} {nameof(IndentSize)} = {IndentSize}";
 
-    public static IndentationAnalysis Create(SyntaxNode node, CancellationToken cancellationToken = default)
+    public static IndentationAnalysis Create(SyntaxNode node, AnalyzerConfigOptions configOptions, CancellationToken cancellationToken = default)
     {
         SyntaxTrivia indentation = SyntaxTriviaAnalysis.DetermineIndentation(node, cancellationToken);
 
+        if (configOptions.TryGetIndentStyle(out IndentStyle indentStyle)
+            && indentStyle == Roslynator.IndentStyle.Tab)
+        {
+            if (!configOptions.TryGetTabLength(out int tabLength))
+                tabLength = 4;
+
+            return new IndentationAnalysis(indentation, indentStyle, tabLength, null);
+        }
+        else if (configOptions.TryGetIndentSize(out int indentSize))
+        {
+            return new IndentationAnalysis(indentation, Roslynator.IndentStyle.Space, indentSize, null);
+        }
+
         (SyntaxTrivia trivia1, SyntaxTrivia trivia2, bool isFromCompilationUnit) = DetermineSingleIndentation(node, cancellationToken);
 
         if (isFromCompilationUnit)
         {
-            return new IndentationAnalysis(indentation, trivia1.Span.Length - trivia2.Span.Length, null);
+            return new IndentationAnalysis(indentation, null, trivia1.Span.Length - trivia2.Span.Length, null);
         }
         else if (indentation.Span.Length > 0)
         {
             return (trivia1.Span.Length > 0)
-                ? new IndentationAnalysis(indentation, null, trivia1)
-                : new IndentationAnalysis(indentation, null, null);
+                ? new IndentationAnalysis(indentation, null, null, trivia1)
+                : new IndentationAnalysis(indentation, null, null, null);
         }
         else if (trivia1.Span.Length > 0)
         {
-            return new IndentationAnalysis(indentation, null, trivia1);
+            return new IndentationAnalysis(indentation, null, null, trivia1);
         }
         else
         {
@@ -87,11 +111,14 @@ public SyntaxTriviaList GetIncreasedIndentationTriviaList()
 
     public string GetSingleIndentation()
     {
-        if (_singleIndentation is not null)
-            return _singleIndentation.ToString();
+        if (_indentStep is not null)
+            return _indentStep.ToString();
+
+        if (IndentStyle == Roslynator.IndentStyle.Tab)
+            return "\t";
 
-        if (_indentSize == -1)
-            return Indentation.ToString();
+        if (IndentStyle == Roslynator.IndentStyle.Space)
+            return GetSpaces();
 
         if (Indentation.Span.Length == 0)
             return "";
@@ -101,7 +128,18 @@ public string GetSingleIndentation()
         if (indentation[indentation.Length - 1] == '\t')
             return "\t";
 
-        return new string(indentation[0], IndentSize);
+        return GetSpaces();
+
+        string GetSpaces()
+        {
+            return IndentSize switch
+            {
+                2 => "  ",
+                4 => "    ",
+                8 => "        ",
+                _ => new string(' ', IndentSize),
+            };
+        }
     }
 
     private static (SyntaxTrivia, SyntaxTrivia, bool isFromCompilationUnit) DetermineSingleIndentation(SyntaxNode node, CancellationToken cancellationToken = default)

src/CSharp/CSharp/SyntaxTriviaAnalysis.cs → src/Common/CSharp/SyntaxTriviaAnalysis.cs

@@ -7,6 +7,7 @@
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.Text;
 using Roslynator.CSharp;
 using Roslynator.Text;
@@ -201,9 +202,9 @@ public static bool StartsWithOptionalWhitespaceThenEndOfLineTrivia(SyntaxTriviaL
         return en.Current.IsEndOfLineTrivia();
     }
 
-    public static IndentationAnalysis AnalyzeIndentation(SyntaxNode node, CancellationToken cancellationToken = default)
+    public static IndentationAnalysis AnalyzeIndentation(SyntaxNode node, AnalyzerConfigOptions configOptions, CancellationToken cancellationToken = default)
     {
-        return IndentationAnalysis.Create(node, cancellationToken);
+        return IndentationAnalysis.Create(node, configOptions, cancellationToken);
     }
 
     public static SyntaxTrivia DetermineIndentation(SyntaxNodeOrToken nodeOrToken, CancellationToken cancellationToken = default)
@@ -302,24 +303,19 @@ static bool IsMemberDeclarationOrStatementOrAccessorDeclaration(SyntaxNode node)
         }
     }
 
-    public static string GetIncreasedIndentation(SyntaxNode node, CancellationToken cancellationToken = default)
+    public static string GetIncreasedIndentation(SyntaxNode node, AnalyzerConfigOptions configOptions, CancellationToken cancellationToken = default)
     {
-        return AnalyzeIndentation(node, cancellationToken).GetIncreasedIndentation();
+        return AnalyzeIndentation(node, configOptions, cancellationToken).GetIncreasedIndentation();
     }
 
-    public static int GetIncreasedIndentationLength(SyntaxNode node, CancellationToken cancellationToken = default)
+    public static SyntaxTrivia GetIncreasedIndentationTrivia(SyntaxNode node, AnalyzerConfigOptions configOptions, CancellationToken cancellationToken = default)
     {
-        return AnalyzeIndentation(node, cancellationToken).IncreasedIndentationLength;
+        return AnalyzeIndentation(node, configOptions, cancellationToken).GetIncreasedIndentationTrivia();
     }
 
-    public static SyntaxTrivia GetIncreasedIndentationTrivia(SyntaxNode node, CancellationToken cancellationToken = default)
+    public static SyntaxTriviaList GetIncreasedIndentationTriviaList(SyntaxNode node, AnalyzerConfigOptions configOptions, CancellationToken cancellationToken = default)
     {
-        return AnalyzeIndentation(node, cancellationToken).GetIncreasedIndentationTrivia();
-    }
-
-    public static SyntaxTriviaList GetIncreasedIndentationTriviaList(SyntaxNode node, CancellationToken cancellationToken = default)
-    {
-        return AnalyzeIndentation(node, cancellationToken).GetIncreasedIndentationTriviaList();
+        return AnalyzeIndentation(node, configOptions, cancellationToken).GetIncreasedIndentationTriviaList();
     }
 
     public static IEnumerable<IndentationInfo> FindIndentations(SyntaxNode node)
@@ -367,9 +363,10 @@ public static IEnumerable<IndentationInfo> FindIndentations(SyntaxNode node, Tex
     public static TNode SetIndentation<TNode>(
         TNode expression,
         SyntaxNode containingDeclaration,
+        AnalyzerConfigOptions configOptions,
         int increaseCount = 0) where TNode : SyntaxNode
     {
-        IndentationAnalysis analysis = AnalyzeIndentation(containingDeclaration);
+        IndentationAnalysis analysis = AnalyzeIndentation(containingDeclaration, configOptions);
 
         string replacement = (increaseCount > 0)
             ? string.Concat(Enumerable.Repeat(analysis.GetSingleIndentation(), increaseCount))

src/Common/ConfigOptionKeys.Generated.cs

@@ -35,6 +35,7 @@ internal static partial class ConfigOptionKeys
         public const string ObjectCreationTypeStyle                           = "roslynator_object_creation_type_style";
         public const string PrefixFieldIdentifierWithUnderscore               = "roslynator_prefix_field_identifier_with_underscore";
         public const string SuppressUnityScriptMethods                        = "roslynator_suppress_unity_script_methods";
+        public const string TabLength                                         = "roslynator_tab_length";
         public const string UseAnonymousFunctionOrMethodGroup                 = "roslynator_use_anonymous_function_or_method_group";
         public const string UseBlockBodyWhenDeclarationSpansOverMultipleLines = "roslynator_use_block_body_when_declaration_spans_over_multiple_lines";
         public const string UseBlockBodyWhenExpressionSpansOverMultipleLines  = "roslynator_use_block_body_when_expression_spans_over_multiple_lines";

src/Common/ConfigOptions.Generated.cs

@@ -182,6 +182,12 @@ public static partial class ConfigOptions
             defaultValuePlaceholder: "true|false", 
             description:             "Suppress Unity script methods");
 
+        public static readonly ConfigOptionDescriptor TabLength = new(
+            key:                     ConfigOptionKeys.TabLength, 
+            defaultValue:            "4", 
+            defaultValuePlaceholder: "<NUM>", 
+            description:             "A length of a tab character.");
+
         public static readonly ConfigOptionDescriptor UseAnonymousFunctionOrMethodGroup = new(
             key:                     ConfigOptionKeys.UseAnonymousFunctionOrMethodGroup, 
             defaultValue:            null, 

src/Common/IndentStyle.cs

@@ -0,0 +1,9 @@
+// Copyright (c) Josef Pihrt and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Roslynator;
+
+public enum IndentStyle
+{
+    Space,
+    Tab,
+}

src/ConfigOptions.xml

@@ -124,6 +124,11 @@
     <ValuePlaceholder>&lt;NUM&gt;</ValuePlaceholder>
     <Description>Max line length</Description>
   </Option>
+  <Option Id="TabLength">
+    <DefaultValue>4</DefaultValue>
+    <ValuePlaceholder>&lt;NUM&gt;</ValuePlaceholder>
+    <Description>A number of spaces that are equivalent to a tab character.</Description>
+  </Option>
   <Option Id="NewLineAtEndOfFile">
     <ValuePlaceholder>true|false</ValuePlaceholder>
     <Description>Include/omit new line at the end of a file</Description>