Merge pull request swiftlang#148 from google/fix-protocol-functions

Fix crash for functions inside protocols.

Author: dabelknap

Sources/SwiftFormatPrettyPrint/TokenStreamCreator.swift

@@ -808,6 +808,10 @@ private final class TokenStreamCreator: SyntaxVisitor {
       }
       after(body.leftBrace, tokens: .close, .close, .break(offset: 2), .open(.consistent, 0))
       before(body.rightBrace, tokens: .break(offset: -2), .close)
+    } else {
+      // FunctionDecls in protocols won't have bodies, so make sure we close the correct number of
+      // groups in that case as well.
+      after(node.lastToken, tokens: .close, .close)
     }
 
     after(node.lastToken, tokens: .close)
@@ -838,6 +842,10 @@ private final class TokenStreamCreator: SyntaxVisitor {
       }
       after(body.leftBrace, tokens: .close, .close, .break(offset: 2), .open(.consistent, 0))
       before(body.rightBrace, tokens: .break(offset: -2), .close)
+    } else {
+      // FunctionDecls in protocols won't have bodies, so make sure we close the correct number of
+      // groups in that case as well.
+      after(node.lastToken, tokens: .close, .close)
     }
 
     after(node.lastToken, tokens: .close)

Tests/SwiftFormatPrettyPrintTests/ProtocolDeclTests.swift

@@ -141,4 +141,52 @@ public class ProtocolDeclTests: PrettyPrintTestCase {
 
     assertPrettyPrintEqual(input: input, expected: expected, linelength: 60)
   }
+
+  public func testProtocolWithFunctions() {
+    let input =
+      """
+      protocol MyProtocol {
+        func foo(bar: Int) -> Int
+        func reallyLongName(reallyLongLabel: Int, anotherLongLabel: Bool) -> Float
+      }
+      """
+    
+    let expected =
+      """
+      protocol MyProtocol {
+        func foo(bar: Int) -> Int
+        func reallyLongName(
+          reallyLongLabel: Int,
+          anotherLongLabel: Bool
+        ) -> Float
+      }
+
+      """
+    
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 30)
+  }
+
+  public func testProtocolWithInitializers() {
+    let input =
+      """
+      protocol MyProtocol {
+        init(bar: Int)
+        init(reallyLongLabel: Int, anotherLongLabel: Bool)
+      }
+      """
+    
+    let expected =
+      """
+      protocol MyProtocol {
+        init(bar: Int)
+        init(
+          reallyLongLabel: Int,
+          anotherLongLabel: Bool
+        )
+      }
+
+      """
+    
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 30)
+  }
 }