Preserve relative indentation in commented-out code

Rules/UseConsistentIndentation.cs

@@ -275,17 +275,15 @@ public override IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string file
                                 ++tempIndentationLevel;
                             }
 
-                            // check for comments in between multi-line commands with line continuation
+                            // Check for comments in between multi-line commands with line continuation.
                             if (tokenIndex > 2 && tokens[tokenIndex - 1].Kind == TokenKind.NewLine
                                 && tokens[tokenIndex - 2].Kind == TokenKind.Comment)
                             {
-                                int searchForPrecedingLineContinuationIndex = tokenIndex - 2;
-                                while (searchForPrecedingLineContinuationIndex  > 0 && tokens[searchForPrecedingLineContinuationIndex].Kind == TokenKind.Comment)
-                                {
-                                    searchForPrecedingLineContinuationIndex--;
-                                }
-
-                                if (searchForPrecedingLineContinuationIndex >= 0 && tokens[searchForPrecedingLineContinuationIndex].Kind == TokenKind.LineContinuation)
+                                GetCommentRunIndentationOffset(
+                                    tokens,
+                                    tokenIndex - 2,
+                                    out bool commentRunStartsAfterLineContinuation);
+                                if (commentRunStartsAfterLineContinuation)
                                 {
                                     tempIndentationLevel++;
                                 }
@@ -298,9 +296,17 @@ public override IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string file
                             }
 
                             bool lineHasPipelineBeforeToken = LineHasPipelineBeforeToken(tokens, tokenIndex, token);
-                            int commentIndentationOffset = token.Kind == TokenKind.Comment
-                                ? GetCommentRunIndentationOffset(tokens, tokenIndex)
-                                : 0;
+                            int commentIndentationOffset = 0;
+                            if (token.Kind == TokenKind.Comment)
+                            {
+                                commentIndentationOffset = GetCommentRunIndentationOffset(
+                                    tokens,
+                                    tokenIndex,
+                                    out bool commentRunStartsAfterLineContinuation);
+                                tempIndentationLevel = indentationLevel +
+                                    (commentRunStartsAfterLineContinuation ? 1 : 0);
+                            }
+
                             AddViolation(token, tempIndentationLevel, diagnosticRecords, ref onNewLine, lineHasPipelineBeforeToken, commentIndentationOffset);
                         }
                         break;
@@ -339,18 +345,25 @@ public override IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string file
             return diagnosticRecords;
         }
 
-        private static int GetCommentRunIndentationOffset(Token[] tokens, int tokenIndex)
+        private static int GetCommentRunIndentationOffset(
+            Token[] tokens,
+            int tokenIndex,
+            out bool commentRunStartsAfterLineContinuation)
         {
             int firstCommentIndex = tokenIndex;
             int currentLine = tokens[tokenIndex].Extent.StartLineNumber;
             int precedingIndex = tokenIndex - 1;
-            while (precedingIndex >= 0 && tokens[precedingIndex].Kind == TokenKind.NewLine)
+            while (precedingIndex >= 0 &&
+                (tokens[precedingIndex].Kind == TokenKind.NewLine ||
+                    tokens[precedingIndex].Kind == TokenKind.LineContinuation))
             {
                 precedingIndex--;
                 if (precedingIndex < 0 ||
                     tokens[precedingIndex].Kind != TokenKind.Comment ||
                     tokens[precedingIndex].Extent.EndLineNumber != currentLine - 1 ||
-                    (precedingIndex > 0 && tokens[precedingIndex - 1].Kind != TokenKind.NewLine))
+                    (precedingIndex > 0 &&
+                        tokens[precedingIndex - 1].Kind != TokenKind.NewLine &&
+                        tokens[precedingIndex - 1].Kind != TokenKind.LineContinuation))
                 {
                     break;
                 }
@@ -360,10 +373,14 @@ private static int GetCommentRunIndentationOffset(Token[] tokens, int tokenIndex
                 precedingIndex--;
             }
 
+            commentRunStartsAfterLineContinuation =
+                firstCommentIndex > 0 &&
+                tokens[firstCommentIndex - 1].Kind == TokenKind.LineContinuation;
             int leastIndentedColumn = tokens[firstCommentIndex].Extent.StartColumnNumber;
             for (int nextCommentIndex = firstCommentIndex + 2;
                 nextCommentIndex < tokens.Length &&
-                    tokens[nextCommentIndex - 1].Kind == TokenKind.NewLine &&
+                    (tokens[nextCommentIndex - 1].Kind == TokenKind.NewLine ||
+                        tokens[nextCommentIndex - 1].Kind == TokenKind.LineContinuation) &&
                     tokens[nextCommentIndex].Kind == TokenKind.Comment &&
                     tokens[nextCommentIndex].Extent.StartLineNumber == tokens[nextCommentIndex - 2].Extent.EndLineNumber + 1;
                 nextCommentIndex += 2)

Tests/Rules/UseConsistentIndentation.tests.ps1

@@ -254,6 +254,20 @@ function foo {
                 Should -Be $expectedScriptDefinition
         }
 
+        It 'Should preserve relative indentation in comments after a line continuation' {
+            $scriptDefinition = @'
+Write-Output `
+    # first
+        # nested
+    # last
+    -InputObject 'value'
+'@
+            $settings.Rules.PSUseConsistentIndentation.PipelineIndentation = 'NoIndentation'
+
+            Invoke-Formatter -ScriptDefinition $scriptDefinition -Settings $settings |
+                Should -Be $scriptDefinition
+        }
+
         It 'Should preserve indentation when the first comment is not the least-indented with <Kind> indentation' -TestCases @(
             @{ Kind = 'space'; Indentation = '    ' }
             @{ Kind = 'tab'; Indentation = "`t" }
@@ -269,6 +283,57 @@ function foo {
             Invoke-Formatter -ScriptDefinition $scriptDefinition -Settings $settings |
                 Should -Be $scriptDefinition
         }
+
+        It 'Should preserve a comment run containing an internal line continuation with <Kind> indentation' -TestCases @(
+            @{ Kind = 'space'; Indentation = '    ' }
+            @{ Kind = 'tab'; Indentation = "`t" }
+        ) {
+            param([string] $Kind, [string] $Indentation)
+            $scriptDefinition = @(
+                '<# first #> `'
+                "$Indentation<# second #>"
+                "Write-Output 'after'"
+            ) -join "`n"
+            $settings.Rules.PSUseConsistentIndentation.Kind = $Kind
+
+            $violations = Invoke-ScriptAnalyzer -ScriptDefinition $scriptDefinition -Settings $settings
+            $violations.Count | Should -Be 0
+            $formatted = Invoke-Formatter -ScriptDefinition $scriptDefinition -Settings $settings
+            $formatted | Should -Be $scriptDefinition
+            Invoke-Formatter -ScriptDefinition $formatted -Settings $settings |
+                Should -Be $formatted
+        }
+
+        It 'Should shift a comment run containing an internal line continuation uniformly with <Kind> indentation' -TestCases @(
+            @{ Kind = 'space'; Indentation = '    ' }
+            @{ Kind = 'tab'; Indentation = "`t" }
+        ) {
+            param([string] $Kind, [string] $Indentation)
+            $scriptDefinition = @(
+                'if ($a) {'
+                '<# first #> `'
+                "$Indentation<# second #>"
+                "$($Indentation)Write-Output 'after'"
+                '}'
+            ) -join "`n"
+            $expectedScriptDefinition = @(
+                'if ($a) {'
+                "$Indentation<# first #> ``"
+                "$Indentation$Indentation<# second #>"
+                "$($Indentation)Write-Output 'after'"
+                '}'
+            ) -join "`n"
+            $settings.Rules.PSUseConsistentIndentation.Kind = $Kind
+
+            $violations = Invoke-ScriptAnalyzer -ScriptDefinition $scriptDefinition -Settings $settings
+            $violations.Count | Should -Be 2
+            $formatted = Invoke-Formatter -ScriptDefinition $scriptDefinition -Settings $settings
+            $formatted | Should -Be $expectedScriptDefinition
+            Invoke-Formatter -ScriptDefinition $formatted -Settings $settings |
+                Should -Be $formatted
+            $violations = Invoke-ScriptAnalyzer -ScriptDefinition $formatted -Settings $settings
+            $violations.Count | Should -Be 0
+        }
     }
 
     Context "When a multi-line command is given" {

docs/Rules/UseConsistentIndentation.md

@@ -15,6 +15,9 @@ title: UseConsistentIndentation
 This rule detects inconsistent indentation patterns within a source file. Indentation should be
 consistent throughout your script.
 
+Consecutive comment lines are shifted together to preserve their relative indentation, including
+when a line continuation occurs within the comment run.
+
 ## Example
 
 ### Noncompliant