Format list patterns (#57568)

src/EditorFeatures/CSharpTest/AutomaticCompletion/AutomaticBracketCompletionTests.cs

@@ -258,7 +258,16 @@ class C
 {
     void M(object o)
     {
-        _ = o is $$
+        _ = o is$$
+    }
+}
+";
+            var expectedBeforeReturn = @"
+class C
+{
+    void M(object o)
+    {
+        _ = o is []
     }
 }
 ";
@@ -267,17 +276,17 @@ class C
 {
     void M(object o)
     {
-        _ = o is [
-]
+        _ = o is
+        [
+
+        ]
     }
 }
 ";
             using var session = CreateSession(code);
             CheckStart(session.Session);
-            // Open bracket probably should be moved to new line
-            // Close bracket probably should be aligned with open bracket
-            // Tracked by https://github.com/dotnet/roslyn/issues/57244
-            CheckReturn(session.Session, 0, expected);
+            CheckText(session.Session, expectedBeforeReturn);
+            CheckReturn(session.Session, 12, expected);
         }
 
         internal static Holder CreateSession(string code)

src/EditorFeatures/CSharpTest/Formatting/Indentation/SmartIndenterEnterOnTokenTests.cs

@@ -1369,12 +1369,10 @@ void Main(object o)
         ]
     }
 }";
-            // Expected indentation probably should be 12 instead
-            // Tracked by https://github.com/dotnet/roslyn/issues/57244
             await AssertIndentNotUsingSmartTokenFormatterButUsingIndenterAsync(
                 code,
                 indentationLine: 7,
-                expectedIndentation: 8);
+                expectedIndentation: 12);
         }
 
         [Trait(Traits.Feature, Traits.Features.SmartIndent)]

src/Features/CSharp/Portable/BraceCompletion/AbstractCurlyBraceOrBracketCompletionService.cs

@@ -0,0 +1,268 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Immutable;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.BraceCompletion;
+using Microsoft.CodeAnalysis.Formatting;
+using Microsoft.CodeAnalysis.Formatting.Rules;
+using Microsoft.CodeAnalysis.Indentation;
+using Microsoft.CodeAnalysis.Options;
+using Microsoft.CodeAnalysis.PooledObjects;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+using Microsoft.CodeAnalysis.Text;
+using Roslyn.Utilities;
+
+namespace Microsoft.CodeAnalysis.CSharp.BraceCompletion
+{
+    internal abstract class AbstractCurlyBraceOrBracketCompletionService : AbstractBraceCompletionService
+    {
+        /// <summary>
+        /// Annotation used to find the closing brace location after formatting changes are applied.
+        /// The closing brace location is then used as the caret location.
+        /// </summary>
+        private static readonly SyntaxAnnotation s_closingBraceSyntaxAnnotation = new(nameof(s_closingBraceSyntaxAnnotation));
+
+        protected abstract ImmutableArray<AbstractFormattingRule> GetBraceFormattingIndentationRulesAfterReturn(IndentationOptions options);
+
+        protected abstract int AdjustFormattingEndPoint(SourceText text, SyntaxNode root, int startPoint, int endPoint);
+
+        public sealed override async Task<BraceCompletionResult?> GetTextChangesAfterCompletionAsync(BraceCompletionContext context, IndentationOptions options, CancellationToken cancellationToken)
+        {
+            // After the closing brace is completed we need to format the span from the opening point to the closing point.
+            // E.g. when the user triggers completion for an if statement ($$ is the caret location) we insert braces to get
+            // if (true){$$}
+            // We then need to format this to
+            // if (true) { $$}
+
+            if (!options.AutoFormattingOptions.FormatOnCloseBrace)
+            {
+                return null;
+            }
+
+            var (formattingChanges, finalCurlyBraceEnd) = await FormatTrackingSpanAsync(
+                context.Document,
+                context.OpeningPoint,
+                context.ClosingPoint,
+                // We're not trying to format the indented block here, so no need to pass in additional rules.
+                braceFormattingIndentationRules: ImmutableArray<AbstractFormattingRule>.Empty,
+                options,
+                cancellationToken).ConfigureAwait(false);
+
+            if (formattingChanges.IsEmpty)
+            {
+                return null;
+            }
+
+            // The caret location should be at the start of the closing brace character.
+            var originalText = await context.Document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+            var formattedText = originalText.WithChanges(formattingChanges);
+            var caretLocation = formattedText.Lines.GetLinePosition(finalCurlyBraceEnd - 1);
+
+            return new BraceCompletionResult(formattingChanges, caretLocation);
+        }
+
+        private static bool ContainsOnlyWhitespace(SourceText text, int openingPosition, int closingBraceEndPoint)
+        {
+            // Set the start point to the character after the opening brace.
+            var start = openingPosition + 1;
+            // Set the end point to the closing brace start character position.
+            var end = closingBraceEndPoint - 1;
+
+            for (var i = start; i < end; i++)
+            {
+                if (!char.IsWhiteSpace(text[i]))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        public sealed override async Task<BraceCompletionResult?> GetTextChangeAfterReturnAsync(
+            BraceCompletionContext context,
+            IndentationOptions options,
+            CancellationToken cancellationToken)
+        {
+            var document = context.Document;
+            var closingPoint = context.ClosingPoint;
+            var openingPoint = context.OpeningPoint;
+            var originalDocumentText = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+
+            // check whether shape of the braces are what we support
+            // shape must be either "{|}" or "{ }". | is where caret is. otherwise, we don't do any special behavior
+            if (!ContainsOnlyWhitespace(originalDocumentText, openingPoint, closingPoint))
+            {
+                return null;
+            }
+
+            var openingPointLine = originalDocumentText.Lines.GetLineFromPosition(openingPoint).LineNumber;
+            var closingPointLine = originalDocumentText.Lines.GetLineFromPosition(closingPoint).LineNumber;
+
+            // If there are already multiple empty lines between the braces, don't do anything.
+            // We need to allow a single empty line between the braces to account for razor scenarios where they insert a line.
+            if (closingPointLine - openingPointLine > 2)
+            {
+                return null;
+            }
+
+            // If there is not already an empty line inserted between the braces, insert one.
+            TextChange? newLineEdit = null;
+            var textToFormat = originalDocumentText;
+            if (closingPointLine - openingPointLine == 1)
+            {
+                var newLineString = options.FormattingOptions.NewLine;
+                newLineEdit = new TextChange(new TextSpan(closingPoint - 1, 0), newLineString);
+                textToFormat = originalDocumentText.WithChanges(newLineEdit.Value);
+
+                // Modify the closing point location to adjust for the newly inserted line.
+                closingPoint += newLineString.Length;
+            }
+
+            // Format the text that contains the newly inserted line.
+            var (formattingChanges, newClosingPoint) = await FormatTrackingSpanAsync(
+                document.WithText(textToFormat),
+                openingPoint,
+                closingPoint,
+                braceFormattingIndentationRules: GetBraceFormattingIndentationRulesAfterReturn(options),
+                options,
+                cancellationToken).ConfigureAwait(false);
+
+            closingPoint = newClosingPoint;
+            var formattedText = textToFormat.WithChanges(formattingChanges);
+
+            // Get the empty line between the curly braces.
+            var desiredCaretLine = GetLineBetweenCurlys(closingPoint, formattedText);
+            Debug.Assert(desiredCaretLine.GetFirstNonWhitespacePosition() == null, "the line between the formatted braces is not empty");
+
+            // Set the caret position to the properly indented column in the desired line.
+            var newDocument = document.WithText(formattedText);
+            var newDocumentText = await newDocument.GetTextAsync(cancellationToken).ConfigureAwait(false);
+            var caretPosition = GetIndentedLinePosition(newDocument, newDocumentText, desiredCaretLine.LineNumber, cancellationToken);
+
+            // The new line edit is calculated against the original text, d0, to get text d1.
+            // The formatting edits are calculated against d1 to get text d2.
+            // Merge the formatting and new line edits into a set of whitespace only text edits that all apply to d0.
+            var overallChanges = newLineEdit != null ? GetMergedChanges(newLineEdit.Value, formattingChanges, formattedText) : formattingChanges;
+            return new BraceCompletionResult(overallChanges, caretPosition);
+
+            static TextLine GetLineBetweenCurlys(int closingPosition, SourceText text)
+            {
+                var closingBraceLineNumber = text.Lines.GetLineFromPosition(closingPosition - 1).LineNumber;
+                return text.Lines[closingBraceLineNumber - 1];
+            }
+
+            static LinePosition GetIndentedLinePosition(Document document, SourceText sourceText, int lineNumber, CancellationToken cancellationToken)
+            {
+                var indentationService = document.GetRequiredLanguageService<IIndentationService>();
+                var indentation = indentationService.GetIndentation(document, lineNumber, cancellationToken);
+
+                var baseLinePosition = sourceText.Lines.GetLinePosition(indentation.BasePosition);
+                var offsetOfBacePosition = baseLinePosition.Character;
+                var totalOffset = offsetOfBacePosition + indentation.Offset;
+                var indentedLinePosition = new LinePosition(lineNumber, totalOffset);
+                return indentedLinePosition;
+            }
+
+            static ImmutableArray<TextChange> GetMergedChanges(TextChange newLineEdit, ImmutableArray<TextChange> formattingChanges, SourceText formattedText)
+            {
+                var newRanges = TextChangeRangeExtensions.Merge(
+                    ImmutableArray.Create(newLineEdit.ToTextChangeRange()),
+                    formattingChanges.SelectAsArray(f => f.ToTextChangeRange()));
+
+                using var _ = ArrayBuilder<TextChange>.GetInstance(out var mergedChanges);
+                var amountToShift = 0;
+                foreach (var newRange in newRanges)
+                {
+                    var newTextChangeSpan = newRange.Span;
+                    // Get the text to put in the text change by looking at the span in the formatted text.
+                    // As the new range start is relative to the original text, we need to adjust it assuming the previous changes were applied
+                    // to get the correct start location in the formatted text.
+                    // E.g. with changes
+                    //     1. Insert "hello" at 2
+                    //     2. Insert "goodbye" at 3
+                    // "goodbye" is after "hello" at location 3 + 5 (length of "hello") in the new text.
+                    var newTextChangeText = formattedText.GetSubText(new TextSpan(newRange.Span.Start + amountToShift, newRange.NewLength)).ToString();
+                    amountToShift += (newRange.NewLength - newRange.Span.Length);
+                    mergedChanges.Add(new TextChange(newTextChangeSpan, newTextChangeText));
+                }
+
+                return mergedChanges.ToImmutable();
+            }
+        }
+
+        /// <summary>
+        /// Formats the span between the opening and closing points, options permitting.
+        /// Returns the text changes that should be applied to the input document to 
+        /// get the formatted text and the end of the close curly brace in the formatted text.
+        /// </summary>
+        private async Task<(ImmutableArray<TextChange> textChanges, int finalBraceEnd)> FormatTrackingSpanAsync(
+            Document document,
+            int openingPoint,
+            int closingPoint,
+            ImmutableArray<AbstractFormattingRule> braceFormattingIndentationRules,
+            IndentationOptions options,
+            CancellationToken cancellationToken)
+        {
+            // Annotate the original closing brace so we can find it after formatting.
+            document = await GetDocumentWithAnnotatedClosingBraceAsync(document, closingPoint, cancellationToken).ConfigureAwait(false);
+
+            var text = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+            var root = await document.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
+
+            var startPoint = openingPoint;
+            var endPoint = AdjustFormattingEndPoint(text, root, startPoint, closingPoint);
+
+            if (options.AutoFormattingOptions.IndentStyle == FormattingOptions.IndentStyle.Smart)
+            {
+                // Set the formatting start point to be the beginning of the first word to the left 
+                // of the opening brace location.
+                // skip whitespace
+                while (startPoint >= 0 && char.IsWhiteSpace(text[startPoint]))
+                {
+                    startPoint--;
+                }
+
+                // skip tokens in the first word to the left.
+                startPoint--;
+                while (startPoint >= 0 && !char.IsWhiteSpace(text[startPoint]))
+                {
+                    startPoint--;
+                }
+            }
+
+            var spanToFormat = TextSpan.FromBounds(Math.Max(startPoint, 0), endPoint);
+            var rules = document.GetFormattingRules(spanToFormat, braceFormattingIndentationRules);
+            var services = document.Project.Solution.Workspace.Services;
+            var result = Formatter.GetFormattingResult(
+                root, SpecializedCollections.SingletonEnumerable(spanToFormat), services, options.FormattingOptions, rules, cancellationToken);
+            if (result == null)
+            {
+                return (ImmutableArray<TextChange>.Empty, closingPoint);
+            }
+
+            var newRoot = result.GetFormattedRoot(cancellationToken);
+            var newClosingPoint = newRoot.GetAnnotatedTokens(s_closingBraceSyntaxAnnotation).Single().SpanStart + 1;
+
+            var textChanges = result.GetTextChanges(cancellationToken).ToImmutableArray();
+            return (textChanges, newClosingPoint);
+
+            async Task<Document> GetDocumentWithAnnotatedClosingBraceAsync(Document document, int closingBraceEndPoint, CancellationToken cancellationToken)
+            {
+                var originalRoot = await document.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
+                var closeBraceToken = originalRoot.FindToken(closingBraceEndPoint - 1);
+                Debug.Assert(IsValidClosingBraceToken(closeBraceToken));
+
+                var newCloseBraceToken = closeBraceToken.WithAdditionalAnnotations(s_closingBraceSyntaxAnnotation);
+                var root = originalRoot.ReplaceToken(closeBraceToken, newCloseBraceToken);
+                return document.WithSyntaxRoot(root);
+            }
+        }
+    }
+}

src/Features/CSharp/Portable/BraceCompletion/BracketBraceCompletionService.cs

@@ -3,16 +3,25 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Composition;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.BraceCompletion;
+using Microsoft.CodeAnalysis.CSharp.Formatting;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Formatting.Rules;
 using Microsoft.CodeAnalysis.Host.Mef;
+using Microsoft.CodeAnalysis.Indentation;
+using Microsoft.CodeAnalysis.Options;
+using Microsoft.CodeAnalysis.Text;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp.BraceCompletion
 {
     [Export(LanguageNames.CSharp, typeof(IBraceCompletionService)), Shared]
-    internal class BracketBraceCompletionService : AbstractBraceCompletionService
+    internal class BracketBraceCompletionService : AbstractCurlyBraceOrBracketCompletionService
     {
         [ImportingConstructor]
         [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
@@ -30,5 +39,44 @@ public override Task<bool> AllowOverTypeAsync(BraceCompletionContext context, Ca
         protected override bool IsValidOpeningBraceToken(SyntaxToken token) => token.IsKind(SyntaxKind.OpenBracketToken);
 
         protected override bool IsValidClosingBraceToken(SyntaxToken token) => token.IsKind(SyntaxKind.CloseBracketToken);
+
+        protected override int AdjustFormattingEndPoint(SourceText text, SyntaxNode root, int startPoint, int endPoint)
+            => endPoint;
+
+        protected override ImmutableArray<AbstractFormattingRule> GetBraceFormattingIndentationRulesAfterReturn(IndentationOptions options)
+        {
+            return ImmutableArray.Create(BracketCompletionFormattingRule.Instance);
+        }
+
+        private sealed class BracketCompletionFormattingRule : BaseFormattingRule
+        {
+            public static readonly AbstractFormattingRule Instance = new BracketCompletionFormattingRule();
+
+            public override AdjustNewLinesOperation? GetAdjustNewLinesOperation(in SyntaxToken previousToken, in SyntaxToken currentToken, in NextGetAdjustNewLinesOperation nextOperation)
+            {
+                if (currentToken.IsKind(SyntaxKind.OpenBracketToken) && currentToken.Parent.IsKind(SyntaxKind.ListPattern))
+                {
+                    // For list patterns we format brackets as though they are a block, so when formatting after Return
+                    // we add a newline
+                    return CreateAdjustNewLinesOperation(1, AdjustNewLinesOption.PreserveLines);
+                }
+
+                return base.GetAdjustNewLinesOperation(in previousToken, in currentToken, in nextOperation);
+            }
+
+            public override void AddAlignTokensOperations(List<AlignTokensOperation> list, SyntaxNode node, in NextAlignTokensOperationAction nextOperation)
+            {
+                base.AddAlignTokensOperations(list, node, in nextOperation);
+
+                var bracketPair = node.GetBracketPair();
+                if (bracketPair.IsValidBracketOrBracePair() && node is ListPatternSyntax)
+                {
+                    // For list patterns we format brackets as though they are a block, so ensure the close bracket
+                    // is aligned with the open bracket
+                    AddAlignIndentationOfTokensToBaseTokenOperation(list, node, bracketPair.openBracket,
+                        SpecializedCollections.SingletonEnumerable(bracketPair.closeBracket), AlignTokensOption.AlignIndentationOfTokensToFirstTokenOfBaseTokenLine);
+                }
+            }
+        }
     }
 }