Merge pull request swiftlang#185 from dylansturg/better_if_stmts

Add a consistent group around if-stmts.

Author: allevato

Sources/SwiftFormatPrettyPrint/TokenStreamCreator.swift

@@ -444,6 +444,12 @@ fileprivate final class TokenStreamCreator: SyntaxVisitor {
   // MARK: - Control flow statement nodes
 
   override func visit(_ node: IfStmtSyntax) -> SyntaxVisitorContinueKind {
+    // There may be a consistent breaking group around this node, see `CodeBlockItemSyntax`. This
+    // group is necessary so that breaks around and inside of the conditions aren't forced to break
+    // when the if-stmt spans multiple lines.
+    before(node.conditions.firstToken, tokens: .open)
+    after(node.conditions.lastToken, tokens: .close)
+
     after(node.labelColon, tokens: .space)
     after(node.ifKeyword, tokens: .space)
 
@@ -1287,6 +1293,13 @@ fileprivate final class TokenStreamCreator: SyntaxVisitor {
       appendFormatterIgnored(node: Syntax(node))
       return .skipChildren
     }
+
+    // This group applies to a top-level if-stmt so that all of the bodies will have the same
+    // breaking behavior.
+    if let ifStmt = node.item.as(IfStmtSyntax.self) {
+      before(ifStmt.firstToken, tokens: .open(.consistent))
+      after(ifStmt.lastToken, tokens: .close)
+    }
     return .visitChildren
   }
 

Tests/SwiftFormatPrettyPrintTests/IfStmtTests.swift

@@ -381,7 +381,9 @@ final class IfStmtTests: PrettyPrintTestCase {
             SomeVeryLongTypeNameThatDefinitelyBreaks,
           baz: Baz
         ) = foo(a, b, c, d)
-      { return nil }
+      {
+        return nil
+      }
 
       """
 
@@ -515,4 +517,51 @@ final class IfStmtTests: PrettyPrintTestCase {
 
     assertPrettyPrintEqual(input: input, expected: expected, linelength: 50)
   }
+
+  func testMultipleIfStmts() {
+    let input =
+      """
+      if foo && bar { baz() } else if bar { baz() } else if foo { baz() } else { blargh() }
+      if foo && bar && quxxe { baz() } else if bar { baz() } else if foo { baz() } else if quxxe { baz() } else { blargh() }
+      if let foo = getmyfoo(), let bar = getmybar(), foo.baz && bar.baz { foo() } else { bar() }
+      if let foo = getmyfoo(), let bar = getmybar(), foo.baz && bar.baz && someOtherCondition { foo() } else { bar() }
+      if let foo = getmyfoo(), let bar = getmybar(), foo.baz && bar.baz && someOtherCondition { foo() }
+      """
+
+    let expected =
+      """
+      if foo && bar { baz() } else if bar { baz() } else if foo { baz() } else { blargh() }
+      if foo && bar && quxxe {
+        baz()
+      } else if bar {
+        baz()
+      } else if foo {
+        baz()
+      } else if quxxe {
+        baz()
+      } else {
+        blargh()
+      }
+      if let foo = getmyfoo(), let bar = getmybar(), foo.baz && bar.baz {
+        foo()
+      } else {
+        bar()
+      }
+      if let foo = getmyfoo(), let bar = getmybar(),
+        foo.baz && bar.baz && someOtherCondition
+      {
+        foo()
+      } else {
+        bar()
+      }
+      if let foo = getmyfoo(), let bar = getmybar(),
+        foo.baz && bar.baz && someOtherCondition
+      {
+        foo()
+      }
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 85)
+  }
 }

Tests/SwiftFormatPrettyPrintTests/XCTestManifests.swift

@@ -410,6 +410,7 @@ extension IfStmtTests {
         ("testIfStatement", testIfStatement),
         ("testLabeledIfStmt", testLabeledIfStmt),
         ("testMatchingPatternConditions", testMatchingPatternConditions),
+        ("testMultipleIfStmts", testMultipleIfStmts),
         ("testOptionalBindingConditions", testOptionalBindingConditions),
         ("testParenthesizedClauses", testParenthesizedClauses),
     ]