Fix wrong foratting of multiline string literal

Author: kimdv

Sources/SwiftBasicFormat/BasicFormat.swift

@@ -146,7 +146,7 @@ open class BasicFormat: SyntaxRewriter {
   /// Whether a leading newline on `token` should be added.
   open func requiresLeadingNewline(_ token: TokenSyntax) -> Bool {
     // We don't want to add newlines inside string interpolation
-    if isInsideStringInterpolation(token) {
+    if isInsideStringInterpolation(token) && token.tokenKind != .multilineStringQuote {
       return false
     }
 
@@ -171,7 +171,29 @@ open class BasicFormat: SyntaxRewriter {
       }
     }
 
-    return false
+    let syntaxToken: Syntax = Syntax(token)
+    switch syntaxToken.keyPathInParent {
+    case \StringLiteralExprSyntax.closeQuote:
+      return token.tokenKind == .multilineStringQuote
+    default:
+      return false
+    }
+  }
+
+  /// Whether a trailing newline on `token` should be added.
+  open func requiresTrailingNewline(_ token: TokenSyntax) -> Bool {
+    // We don't want to add newlines inside string interpolation
+    if isInsideStringInterpolation(token) && token.tokenKind != .multilineStringQuote {
+      return false
+    }
+
+    let syntaxToken: Syntax = Syntax(token)
+    switch syntaxToken.keyPathInParent {
+    case \StringLiteralExprSyntax.openQuote:
+      return token.tokenKind == .multilineStringQuote
+    default:
+      return false
+    }
   }
 
   open func requiresWhitespace(between first: TokenSyntax?, and second: TokenSyntax?) -> Bool {
@@ -259,6 +281,15 @@ open class BasicFormat: SyntaxRewriter {
     return true
   }
 
+  open func requiresNewline(between first: TokenSyntax?, and second: TokenSyntax?) -> Bool {
+    switch (first?.tokenKind, second?.tokenKind) {
+    case (.multilineStringQuote, .stringSegment):
+      return true
+    default:
+      return false
+    }
+  }
+
   /// Whether the formatter should consider this token as being mutable.
   /// This allows the diagnostic generator to only assume that missing nodes
   /// will be mutated. Thus, if two tokens need to be separated by a space, it

Sources/SwiftParserDiagnostics/DiagnosticExtensions.swift

@@ -167,11 +167,12 @@ extension FixIt.MultiNodeChange {
       }
     }
 
-    if let previousToken = node.previousToken(viewMode: .all),
+    if let previousToken = node.previousToken(viewMode: .fixedUp),
       previousToken.presence == .present,
       let firstToken = node.firstToken(viewMode: .all),
       previousToken.trailingTrivia.allSatisfy({ $0.isWhitespace }),
-      !BasicFormat().requiresWhitespace(between: previousToken, and: firstToken)
+      !BasicFormat().requiresWhitespace(between: previousToken, and: firstToken),
+      !BasicFormat().requiresNewline(between: previousToken, and: firstToken)
     {
       // If the previous token and this node don't need to be separated, remove
       // the separation.

Sources/SwiftParserDiagnostics/ParseDiagnosticsGenerator.swift

@@ -1252,12 +1252,10 @@ public class ParseDiagnosticsGenerator: SyntaxAnyVisitor {
     }
     if case .stringSegment(let segment) = node.segments.last {
       if let invalidContent = segment.unexpectedBeforeContent?.onlyToken(where: { $0.trailingTrivia.contains(where: { $0.isBackslash }) }) {
-        let leadingTrivia = segment.content.leadingTrivia
-        let trailingTrivia = segment.content.trailingTrivia
         let fixIt = FixIt(
           message: .removeBackslash,
           changes: [
-            .makePresent(segment.content, leadingTrivia: leadingTrivia, trailingTrivia: trailingTrivia),
+            .makePresent(segment.content),
             .makeMissing(invalidContent, transferTrivia: false),
           ]
         )

Tests/SwiftParserTest/ExpressionTests.swift

@@ -603,7 +603,8 @@ final class ExpressionTests: XCTestCase {
         )
       ],
       fixedSource: ##"""
-        """""""
+        """"
+        """
         """##
     )
 
@@ -619,7 +620,8 @@ final class ExpressionTests: XCTestCase {
         )
       ],
       fixedSource: ##"""
-        """"""""
+        """""
+        """
         """##
     )
 
@@ -656,7 +658,8 @@ final class ExpressionTests: XCTestCase {
         DiagnosticSpec(message: ##"expected '"""#' to end string literal"##, fixIts: [##"insert '"""#'"##])
       ],
       fixedSource: ##"""
-        #""""""#
+        #"""
+        """#
         """##
     )
 
@@ -668,7 +671,8 @@ final class ExpressionTests: XCTestCase {
         DiagnosticSpec(message: ##"expected '"""#' to end string literal"##, fixIts: [##"insert '"""#'"##])
       ],
       fixedSource: ##"""
-        #"""a"""#
+        #"""a
+        """#
         """##
     )
 

Tests/SwiftParserTest/translated/AvailabilityQueryTests.swift

@@ -100,7 +100,7 @@ final class AvailabilityQueryTests: XCTestCase {
         DiagnosticSpec(message: "expected ',' joining parts of a multi-clause condition", fixIts: ["replace '&&' with ','"])
       ],
       fixedSource: """
-        if #available(OSX 10.51, *) , #available(OSX 10.52, *) {
+        if #available(OSX 10.51, *), #available(OSX 10.52, *) {
         }
         """
     )
@@ -440,7 +440,7 @@ final class AvailabilityQueryTests: XCTestCase {
         DiagnosticSpec(message: "expected ',' joining platforms in availability condition", fixIts: ["replace '||' with ','"])
       ],
       fixedSource: """
-        if #available(OSX 10.51 , iOS 8.0) {
+        if #available(OSX 10.51, iOS 8.0) {
         }
         """
     )

Tests/SwiftParserTest/translated/AvailabilityQueryUnavailabilityTests.swift

@@ -103,7 +103,7 @@ final class AvailabilityQueryUnavailabilityTests: XCTestCase {
         )
       ],
       fixedSource: """
-        if #unavailable(OSX 10.51) , #unavailable(OSX 10.52) {
+        if #unavailable(OSX 10.51), #unavailable(OSX 10.52) {
         }
         """
     )
@@ -447,7 +447,7 @@ final class AvailabilityQueryUnavailabilityTests: XCTestCase {
         )
       ],
       fixedSource: """
-        if #unavailable(OSX 10.51 , iOS 8.0) {
+        if #unavailable(OSX 10.51, iOS 8.0) {
         }
         """
     )

Tests/SwiftParserTest/translated/MultilineErrorsTests.swift

@@ -705,7 +705,8 @@ final class MultilineErrorsTests: XCTestCase {
       ],
       fixedSource: ##"""
         _ = """
-          foo\"""
+          foo\
+        """
         """##
     )
   }

Tests/SwiftParserTest/translated/MultilinePoundDiagnosticArgRdar41154797Tests.swift

@@ -35,7 +35,8 @@ final class MultilinePoundDiagnosticArgRdar41154797Tests: XCTestCase {
         ),
       ],
       fixedSource: ##"""
-        #error("""""")
+        #error("""
+        """)
         """##
     )
   }

Tests/SwiftParserTest/translated/MultilineStringTests.swift

@@ -411,6 +411,82 @@ final class MultilineStringTests: XCTestCase {
     )
   }
 
+  func testMultilineString47() {
+    assertParse(
+      #"""
+      _ = """1️⃣"""
+      """#,
+      diagnostics: [
+        DiagnosticSpec(
+          message: "multi-line string literal closing delimiter must begin on a new line",
+          fixIts: ["insert newline"]
+        )
+      ],
+      fixedSource: #"""
+        _ = """
+        """
+        """#
+    )
+  }
+
+  func testMultilineString48() {
+    assertParse(
+      #"""
+      _ = """A1️⃣"""
+      """#,
+      diagnostics: [
+        DiagnosticSpec(
+          message: "multi-line string literal closing delimiter must begin on a new line",
+          fixIts: ["insert newline"]
+        )
+      ],
+      fixedSource: #"""
+        _ = """A
+        """
+        """#
+    )
+  }
+
+  func testMultilineString49() {
+    assertParse(
+      #"""
+      _ = ℹ️"""1️⃣
+      """#,
+      diagnostics: [
+        DiagnosticSpec(
+          message: #"expected '"""' to end string literal"#,
+          notes: [NoteSpec(message: #"to match this opening '"""'"#)],
+          fixIts: [#"insert '"""'"#]
+        )
+      ],
+      fixedSource: #"""
+        _ = """
+        """
+        """#
+    )
+  }
+
+  func testMultilineString50() {
+    assertParse(
+      #"""
+      _ = ℹ️"""
+      A1️⃣
+      """#,
+      diagnostics: [
+        DiagnosticSpec(
+          message: #"expected '"""' to end string literal"#,
+          notes: [NoteSpec(message: #"to match this opening '"""'"#)],
+          fixIts: [#"insert '"""'"#]
+        )
+      ],
+      fixedSource: #"""
+        _ = """
+        A
+        """
+        """#
+    )
+  }
+
   func testEscapeNewlineInRawString() {
     assertParse(
       ##"""

Tests/SwiftParserTest/translated/StringLiteralEofTests.swift

@@ -133,7 +133,8 @@ final class StringLiteralEofTests: XCTestCase {
       fixedSource: #"""
         // NOTE: DO NOT add a newline at EOF.
         _ = """
-            foo"""
+            foo
+        """
         """#
     )
   }
@@ -160,7 +161,8 @@ final class StringLiteralEofTests: XCTestCase {
       fixedSource: ##"""
         _ = """
             foo
-            \(<#expression#>)"""
+            \(<#expression#>)
+        """
         """##
       // FIXME: The closing delimiter should be put on the new line
     )
@@ -197,7 +199,8 @@ final class StringLiteralEofTests: XCTestCase {
       fixedSource: ##"""
         _ = """
             foo
-            \("bar")"""
+            \("bar")
+        """
         """##
     )
   }
@@ -236,7 +239,8 @@ final class StringLiteralEofTests: XCTestCase {
       fixedSource: ##"""
         _ = """
             \("bar"
-            baz)"""
+            baz)
+        """
         """##
     )
   }

Tests/SwiftParserTest/translated/UnclosedStringInterpolationTests.swift

@@ -187,7 +187,9 @@ final class UnclosedStringInterpolationTests: XCTestCase {
       fixedSource: ##"""
         _ = """
         \(
-        """""")"""
+        """
+        """)
+        """
         """##
     )
   }