Preserve CR-only line endings when formatting files (#2234)

* Initial plan

* Handle CR-only formatter line endings

Co-authored-by: bergmeister <9250262+bergmeister@users.noreply.github.com>

* Make legacy encoding fixture source-independent

Co-authored-by: bergmeister <9250262+bergmeister@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: bergmeister <9250262+bergmeister@users.noreply.github.com>

Author: Copilot

Engine/Commands/InvokeFormatterCommand.cs

@@ -5,9 +5,11 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Globalization;
+using System.Linq;
 using System.Text;
 using System.Management.Automation;
 using System.Management.Automation.Language;
+using Microsoft.Windows.PowerShell.ScriptAnalyzer.Extensions;
 
 namespace Microsoft.Windows.PowerShell.ScriptAnalyzer.Commands
 {
@@ -239,7 +241,7 @@ private static string GetIndentationKind(string scriptDefinition)
             int spaceIndentedLines = 0;
             string firstIndentationKind = "space";
             bool foundIndentation = false;
-            string[] lines = scriptDefinition.Split('\n');
+            string[] lines = scriptDefinition.GetLines().ToArray();
             Parser.ParseInput(scriptDefinition, out Token[] tokens, out ParseError[] errors);
             var countedLines = new HashSet<int>();
 

Engine/Extensions.cs

@@ -18,7 +18,7 @@ public static class Extensions
         /// <returns></returns>
         public static IEnumerable<string> GetLines(this string text)
         {
-            return text.Split('\n').Select(line => line.TrimEnd('\r'));
+            return text.Split(new[] { "\r\n", "\r", "\n" }, StringSplitOptions.None);
         }
 
         /// <summary>

Tests/Engine/InvokeFormatter.tests.ps1

@@ -54,10 +54,22 @@ Describe "Invoke-Formatter Cmdlet" {
             [System.IO.File]::ReadAllBytes($path)[0..1] | Should -Be @(255, 254)
         }
 
+        It 'Formats a file with CR-only line endings' {
+            $path = Join-Path $TestDrive 'cr-only.ps1'
+            $scriptDefinition = "function foo {`r`t`$x=1`r}"
+            $expected = "function foo {`r`t`$x = 1`r}"
+            [System.IO.File]::WriteAllText($path, $scriptDefinition)
+
+            Invoke-Formatter -Path $path | Should -Be $expected
+
+            [System.IO.File]::ReadAllText($path) | Should -Be $expected
+        }
+
         It 'Best-effort formats BOM-less files using a legacy encoding' {
             $path = Join-Path $TestDrive 'legacy-encoding.ps1'
-            $scriptDefinition = '$name=''café'''
-            $expected = '$name = ''café'''
+            $cafe = 'caf' + [char]0xE9
+            $scriptDefinition = "`$name='$cafe'"
+            $expected = "`$name = '$cafe'"
             $encoding = [System.Text.Encoding]::GetEncoding(1252)
             [System.IO.File]::WriteAllBytes($path, $encoding.GetBytes($scriptDefinition))