Merge pull request swiftlang#135 from allevato/plain-old-unknowns

Flesh out unknown node handling.

Author: allevato

Sources/SwiftFormatPrettyPrint/TokenStreamCreator.swift

@@ -1658,10 +1658,6 @@ private final class TokenStreamCreator: SyntaxVisitor {
     return .visitChildren
   }
 
-  override func visit(_ node: UnknownPatternSyntax) -> SyntaxVisitorContinueKind {
-    return .visitChildren
-  }
-
   override func visit(_ node: SomeTypeSyntax) -> SyntaxVisitorContinueKind {
     after(node.someSpecifier, tokens: .space)
     return .visitChildren
@@ -1937,18 +1933,45 @@ private final class TokenStreamCreator: SyntaxVisitor {
     return .visitChildren
   }
 
+  // MARK: - Nodes representing unknown or malformed syntax
+
   override func visit(_ node: UnknownDeclSyntax) -> SyntaxVisitorContinueKind {
     verbatimToken(Syntax(node))
-    // Visiting children is not needed here.
+    return .skipChildren
+  }
+
+  override func visit(_ node: UnknownExprSyntax) -> SyntaxVisitorContinueKind {
+    verbatimToken(Syntax(node))
+    return .skipChildren
+  }
+
+  override func visit(_ node: UnknownPatternSyntax) -> SyntaxVisitorContinueKind {
+    verbatimToken(Syntax(node))
     return .skipChildren
   }
 
   override func visit(_ node: UnknownStmtSyntax) -> SyntaxVisitorContinueKind {
     verbatimToken(Syntax(node))
-    // Visiting children is not needed here.
     return .skipChildren
   }
 
+  override func visit(_ node: UnknownSyntax) -> SyntaxVisitorContinueKind {
+    verbatimToken(Syntax(node))
+    return .skipChildren
+  }
+
+  override func visit(_ node: UnknownTypeSyntax) -> SyntaxVisitorContinueKind {
+    verbatimToken(Syntax(node))
+    return .skipChildren
+  }
+
+  override func visit(_ node: NonEmptyTokenListSyntax) -> SyntaxVisitorContinueKind {
+    verbatimToken(Syntax(node))
+    return .skipChildren
+  }
+
+  // MARK: - Token handling
+
   override func visit(_ token: TokenSyntax) -> SyntaxVisitorContinueKind {
     // Arrange the tokens and trivia such that before tokens that start a new "scope" (which may
     // increase indentation) are inserted in the stream *before* the leading trivia, but tokens

Tests/SwiftFormatPrettyPrintTests/UnknownDeclTests.swift

@@ -0,0 +1,81 @@
+/// Tests for unknown/malformed nodes that ensure that they are handled as verbatim text so that
+/// their internal tokens do not get squashed together.
+final class UnknownNodeTests: PrettyPrintTestCase {
+  func testUnknownDecl() {
+    let input =
+      """
+      struct MyStruct where {
+        let a = 123
+      }
+      """
+
+    assertPrettyPrintEqual(input: input, expected: input + "\n", linelength: 45)
+  }
+
+  func testUnknownExpr() {
+    let input =
+      """
+      (foo where bar)
+      """
+
+    assertPrettyPrintEqual(input: input, expected: input + "\n", linelength: 45)
+  }
+
+  func testUnknownPattern() {
+    // This one loses the space after the word `case` because the break would normally be
+    // inserted before the first token in the pattern.
+    let input =
+      """
+      if case * ! = x {
+        bar()
+      }
+      """
+
+    let expected =
+      """
+      if case* ! = x {
+        bar()
+      }
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 45)
+  }
+
+  func testUnknownStmt() {
+    let input =
+      """
+      if foo where {
+        bar()
+      }
+      """
+
+    assertPrettyPrintEqual(input: input, expected: input + "\n", linelength: 45)
+  }
+
+  func testUnknownType() {
+    // This one loses the space after the colon because the break would normally be inserted before
+    // the first token in the type name.
+    let input =
+      """
+      let x: where
+      """
+
+    let expected =
+      """
+      let x:where
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 45)
+  }
+
+  func testNonEmptyTokenList() {
+    let input =
+      """
+      @(foo ! @ # bar)
+      """
+
+    assertPrettyPrintEqual(input: input, expected: input + "\n", linelength: 45)
+  }
+}

Tests/SwiftFormatPrettyPrintTests/UnknownNodeTests.swift

@@ -705,12 +705,17 @@ extension TypeAliasTests {
     ]
 }
 
-extension UnknownDeclTests {
+extension UnknownNodeTests {
     // DO NOT MODIFY: This is autogenerated, use:
     //   `swift test --generate-linuxmain`
     // to regenerate.
-    static let __allTests__UnknownDeclTests = [
+    static let __allTests__UnknownNodeTests = [
+        ("testNonEmptyTokenList", testNonEmptyTokenList),
         ("testUnknownDecl", testUnknownDecl),
+        ("testUnknownExpr", testUnknownExpr),
+        ("testUnknownPattern", testUnknownPattern),
+        ("testUnknownStmt", testUnknownStmt),
+        ("testUnknownType", testUnknownType),
     ]
 }
 
@@ -795,7 +800,7 @@ public func __allTests() -> [XCTestCaseEntry] {
         testCase(TryCatchTests.__allTests__TryCatchTests),
         testCase(TupleDeclTests.__allTests__TupleDeclTests),
         testCase(TypeAliasTests.__allTests__TypeAliasTests),
-        testCase(UnknownDeclTests.__allTests__UnknownDeclTests),
+        testCase(UnknownNodeTests.__allTests__UnknownNodeTests),
         testCase(VariableDeclarationTests.__allTests__VariableDeclarationTests),
         testCase(WhileStmtTests.__allTests__WhileStmtTests),
         testCase(YieldStmtTests.__allTests__YieldStmtTests),