Preserve trailing comments for opening_brace rule (realm#5780)

mildm8nnered · Sep 8, 2024 · 9e78054 · 9e78054
1 parent 06e4e3c
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -41,6 +41,11 @@
   [SimplyDanny](https://github.com/SimplyDanny)
   [#4754](https://github.com/realm/SwiftLint/issues/4754)
 
+* Trailing comments are now preserved by the `opening_brace` rule when
+  rewriting.  
+  [Martin Redington](https://github.com/mildm8nnered)
+  [#5751](https://github.com/realm/SwiftLint/issues/5751)
+
 ## 0.56.2: Heat Pump Dryer
 
 #### Breaking

diff --git a/Source/SwiftLintBuiltInRules/Rules/Style/OpeningBraceRule.swift b/Source/SwiftLintBuiltInRules/Rules/Style/OpeningBraceRule.swift
@@ -172,10 +172,11 @@ private extension OpeningBraceRule {
             let previousLocation = previousToken.endLocation(converter: locationConverter)
             let leftBraceLocation = leftBrace.startLocation(converter: locationConverter)
             if previousLocation.line != leftBraceLocation.line {
+                let trailingCommentText = previousToken.trailingTrivia.description.trimmingCharacters(in: .whitespaces)
                 return .init(
                     start: previousToken.endPositionBeforeTrailingTrivia,
-                    end: openingPosition,
-                    replacement: " "
+                    end: openingPosition.advanced(by: trailingCommentText.isNotEmpty ? 1 : 0),
+                    replacement: trailingCommentText.isNotEmpty ? " { \(trailingCommentText)" : " "
                 )
             }
             if previousLocation.column + 1 == leftBraceLocation.column {

diff --git a/Source/SwiftLintBuiltInRules/Rules/Style/OpeningBraceRuleExamples.swift b/Source/SwiftLintBuiltInRules/Rules/Style/OpeningBraceRuleExamples.swift
@@ -547,6 +547,28 @@ struct OpeningBraceRuleExamples {
                 }
             """),
         // https://github.com/realm/SwiftLint/issues/5598
+        Example("""
+            if c    // A comment
+            {
+                return
+            }
+        """): Example("""
+                if c { // A comment
+                    return
+                }
+            """),
+        // https://github.com/realm/SwiftLint/issues/5751
+        Example("""
+            if c    // A comment
+            { // Another comment
+                return
+            }
+        """): Example("""
+                if c { // A comment // Another comment
+                    return
+                }
+            """),
+        // https://github.com/realm/SwiftLint/issues/5751
         Example("""
             func foo() {
                 if q1, q2