Merge pull request swiftlang#181 from dylansturg/class_is_too_long

Rearrange breaks so class decls won't overflow line length.

Author: allevato

Sources/SwiftFormatPrettyPrint/TokenStreamCreator.swift

@@ -1991,10 +1991,11 @@ fileprivate final class TokenStreamCreator: SyntaxVisitor {
   }
 
   override func visit(_ node: TypeInheritanceClauseSyntax) -> SyntaxVisitorContinueKind {
-    after(node.colon, tokens: .break(.open, size: 1))
-    before(node.inheritedTypeCollection.firstToken, tokens: .open)
-    after(node.inheritedTypeCollection.lastToken, tokens: .close)
-    after(node.lastToken, tokens: .break(.close, size: 0))
+    // Normally, the open-break is placed before the open token. In this case, it's intentionally
+    // ordered differently so that the inheritance list can start on the current line and only
+    // breaks if the first item in the list would overflow the column limit.
+    before(node.inheritedTypeCollection.firstToken, tokens: .open, .break(.open, size: 1))
+    after(node.inheritedTypeCollection.lastToken, tokens: .break(.close, size: 0), .close)
     return .visitChildren
   }
 

Tests/SwiftFormatPrettyPrintTests/ClassDeclTests.swift

@@ -140,6 +140,15 @@ final class ClassDeclTests: PrettyPrintTestCase {
         let A: Int
         let B: Bool
       }
+      class MyClass:
+        SuperOne, SuperTwo, SuperThree {
+        let A: Int
+        let B: Bool
+      }
+      class MyClassWhoseNameIsVeryLong: SuperOne, SuperTwo, SuperThree {
+        let A: Int
+        let B: Bool
+      }
       """
 
     let expected =
@@ -158,6 +167,18 @@ final class ClassDeclTests: PrettyPrintTestCase {
         let A: Int
         let B: Bool
       }
+      class MyClass:
+        SuperOne, SuperTwo, SuperThree
+      {
+        let A: Int
+        let B: Bool
+      }
+      class MyClassWhoseNameIsVeryLong:
+        SuperOne, SuperTwo, SuperThree
+      {
+        let A: Int
+        let B: Bool
+      }
 
       """
 

Tests/SwiftFormatPrettyPrintTests/ExtensionDeclTests.swift

@@ -316,8 +316,8 @@ final class ExtensionDeclTests: PrettyPrintTestCase {
     let expected =
 
       """
-      public extension MyContainer: MyContainerProtocolOne,
-        MyContainerProtocolTwo,
+      public extension MyContainer:
+        MyContainerProtocolOne, MyContainerProtocolTwo,
         SomeoneElsesContainerProtocol,
         SomeFrameworkContainerProtocol
       where
@@ -346,8 +346,8 @@ final class ExtensionDeclTests: PrettyPrintTestCase {
     let expected =
 
     """
-      public extension MyContainer: MyContainerProtocolOne,
-        MyContainerProtocolTwo,
+      public extension MyContainer:
+        MyContainerProtocolOne, MyContainerProtocolTwo,
         SomeoneElsesContainerProtocol,
         SomeFrameworkContainerProtocol
       where