Breakdown comment blocks with new lines

This also keeps comment lines within comment blocks with their leading
comment markers in tact

Author: adammcarter

Diff for: Sources/SwiftSyntax/Trivia.swift

@@ -46,10 +46,62 @@ public struct Trivia: Sendable {
   ///
   /// Each element in the array is the trimmed contents of a line comment, or, in the case of a multi-line comment a trimmed, concatenated single string.
   public var commentValues: [String] {
-    [
-      sanitizedLineCommentValues,
-      sanitizedBlockCommentValues,
-    ].flatMap { $0 }
+    var comments = [String]()
+    var partialComments = [String]()
+
+    var foundStartOfCodeBlock = false
+    var foundEndOfCodeBlock = false
+    var isInCodeBlock: Bool { foundStartOfCodeBlock && !foundEndOfCodeBlock }
+
+    for piece in pieces {
+      switch piece {
+      case .blockComment(let text), .docBlockComment(let text):
+        let text = text.trimmingCharacters(in: "\n")
+
+        foundStartOfCodeBlock = text.hasPrefix("/*")
+        foundEndOfCodeBlock = text.hasSuffix("*/")
+
+        let sanitized =
+          text
+          .split(separator: "\n")
+          .map { $0.trimmingAnyCharacters(in: "/*").trimmingAnyCharacters(in: " ") }
+          .filter { !$0.isEmpty }
+          .joined(separator: " ")
+
+        appendPartialCommentIfPossible(sanitized)
+
+      case .lineComment(let text), .docLineComment(let text):
+        if isInCodeBlock {
+          appendPartialCommentIfPossible(text)
+        } else {
+          comments.append(String(text.trimmingPrefix("/ ")))
+        }
+
+      default:
+        break
+      }
+
+      if foundEndOfCodeBlock, !partialComments.isEmpty {
+        appendSubstringsToLines()
+        partialComments.removeAll()
+      }
+    }
+
+    if !partialComments.isEmpty {
+      appendSubstringsToLines()
+    }
+
+    func appendPartialCommentIfPossible(_ text: String) {
+      guard partialComments.isEmpty || !text.isEmpty else { return }
+
+      partialComments.append(text)
+    }
+
+    func appendSubstringsToLines() {
+      comments.append(partialComments.joined(separator: " "))
+    }
+
+    return comments
   }
 
   /// The length of all the pieces in this ``Trivia``.
@@ -225,54 +277,3 @@ extension RawTriviaPiece: CustomDebugStringConvertible {
     TriviaPiece(raw: self).debugDescription
   }
 }
-
-private extension Trivia {
-  var sanitizedLineCommentValues: [String] {
-    compactMap {
-      switch $0 {
-      case .lineComment(let text), .docLineComment(let text):
-        String(sanitizingLineComment(text))
-
-      default:
-        nil
-      }
-    }
-  }
-
-  func sanitizingLineComment(_ text: String) -> Substring {
-    text.trimmingPrefix("/ ")
-  }
-
-  var sanitizedBlockCommentValues: [String] {
-    var lines = [String]()
-    var substrings = [Substring]()
-    var foundTerminator = false
-
-    for piece in self {
-      switch piece {
-      case .blockComment(let text), .docBlockComment(let text):
-        let sanitized = text.trimmingCharacters(in: "/* ")
-
-        if substrings.isEmpty || sanitized.isEmpty == false {
-          substrings.append(sanitized)
-        }
-
-        foundTerminator = text.hasSuffix("*/")
-
-      default:
-        break
-      }
-
-      if foundTerminator, substrings.isEmpty == false {
-        lines.append(substrings.joined(separator: " "))
-        substrings.removeAll()
-      }
-    }
-
-    if substrings.isEmpty == false {
-      lines.append(substrings.joined(separator: " "))
-    }
-
-    return lines
-  }
-}

Diff for: Sources/SwiftSyntax/Utils.swift

@@ -124,24 +124,28 @@ extension RawUnexpectedNodesSyntax {
 extension String {
   func trimmingCharacters(in charactersToTrim: any BidirectionalCollection<Character>) -> Substring {
     // TODO: adammcarter - this feels a bit dirty
-    self[startIndex...].trimmingPrefix(charactersToTrim).trimmingSuffix(charactersToTrim)
+    self[startIndex...].trimmingAnyCharacters(in: charactersToTrim)
   }
 
   func trimmingPrefix(_ charactersToTrim: any BidirectionalCollection<Character>) -> Substring {
-    self[startIndex...].trimmingPrefix(charactersToTrim)
+    self[startIndex...].trimmingAnyCharactersFromPrefix(in: charactersToTrim)
   }
 
   func trimmingSuffix(_ charactersToTrim: any BidirectionalCollection<Character>) -> Substring {
-    self[startIndex...].trimmingSuffix(charactersToTrim)
+    self[startIndex...].trimmingAnyCharactersFromSuffix(in: charactersToTrim)
   }
 }
 
 extension Substring {
-  func trimmingPrefix(_ charactersToTrim: any BidirectionalCollection<Character>) -> Self {
+  func trimmingAnyCharacters(in charactersToTrim: any BidirectionalCollection<Character>) -> Substring {
+    trimmingAnyCharactersFromPrefix(in: charactersToTrim).trimmingAnyCharactersFromSuffix(in: charactersToTrim)
+  }
+
+  func trimmingAnyCharactersFromPrefix(in charactersToTrim: any BidirectionalCollection<Character>) -> Self {
     dropFirst(countOfSequentialCharacters(charactersToTrim, in: self))
   }
 
-  func trimmingSuffix(_ charactersToTrim: any BidirectionalCollection<Character>) -> Self {
+  func trimmingAnyCharactersFromSuffix(in charactersToTrim: any BidirectionalCollection<Character>) -> Self {
     dropLast(countOfSequentialCharacters(charactersToTrim, in: reversed()))
   }
 }

Diff for: Tests/SwiftSyntaxTest/TriviaTests.swift

@@ -214,6 +214,34 @@ class TriviaTests: XCTestCase {
       ]
     )
 
+    XCTAssertEqual(
+      Trivia(pieces: [
+        .blockComment(
+          """
+          /*
+          Some block comment
+          spread on many lines
+          */
+          """
+        )
+      ]).commentValues,
+      ["Some block comment spread on many lines"]
+    )
+
+    XCTAssertEqual(
+      Trivia(pieces: [
+        .blockComment(
+          """
+          /*
+          *  Some block comment
+          *  spread on many lines
+          */
+          """
+        )
+      ]).commentValues,
+      ["Some block comment spread on many lines"]
+    )
+
     // MARK: doc block comment
 
     XCTAssertEqual(
@@ -277,7 +305,89 @@ class TriviaTests: XCTestCase {
       ]
     )
 
-    // TODO: adammcarter - mixing trivia of lines and blocks
-    // TODO: adammcarter - newline chars in the prefix/suffix of code block too
+    XCTAssertEqual(
+      Trivia(pieces: [
+        .docBlockComment(
+          """
+          /**
+          Some doc block comment
+          spread on many lines
+          */
+          """
+        )
+      ]).commentValues,
+      ["Some doc block comment spread on many lines"]
+    )
+
+    XCTAssertEqual(
+      Trivia(pieces: [
+        .docBlockComment(
+          """
+          /**
+          *  Some doc block comment
+          *  spread on many lines
+          */
+          """
+        )
+      ]).commentValues,
+      ["Some doc block comment spread on many lines"]
+    )
+
+    // MARK: Mixing comment styles
+
+    XCTAssertEqual(
+      Trivia(pieces: [
+        .docBlockComment(
+          """
+          /**
+          *  Some doc block comment
+          *  // spread on many lines
+          *  with a line comment
+          */
+          """
+        )
+      ]).commentValues,
+      ["Some doc block comment // spread on many lines with a line comment"]
+    )
+
+    XCTAssertEqual(
+      Trivia(pieces: [
+        .docBlockComment("/** Some doc block comment"),
+        .docBlockComment("* spread on many lines */"),
+        .newlines(2),
+        .docLineComment("/// Some doc line comment"),
+        .docLineComment("// Some line comment"),
+        .newlines(2),
+        .spaces(4),
+        .blockComment("/* Some block comment"),
+        .blockComment("* spread on many lines */"),
+        .newlines(2),
+        .docBlockComment("/** Another doc block comment */"),
+      ]).commentValues,
+      [
+        "Some doc block comment spread on many lines",
+        "Some doc line comment",
+        "Some line comment",
+        "Some block comment spread on many lines",
+        "Another doc block comment",
+      ]
+    )
+
+    XCTAssertEqual(
+      Trivia(pieces: [
+        .docBlockComment("/* Some block comment"),
+        .docLineComment("// A line comment in a block"),
+        .docBlockComment("* spread on many lines */"),
+        .newlines(2),
+        .blockComment("/** Some doc block comment"),
+        .docLineComment("/// A doc line comment in a block"),
+        .blockComment("* spread on"),
+        .blockComment("* many lines */"),
+      ]).commentValues,
+      [
+        "Some block comment // A line comment in a block spread on many lines",
+        "Some doc block comment /// A doc line comment in a block spread on many lines",
+      ]
+    )
   }
 }