Updates for recent syntax/toolchain changes.

- Remove differentiation nodes that no longer exist.
- Add support for multiple `catch` clauses (SE-0276).
- Remove a never-used configuration helper type that
  incorrectly used a `let`-with-initial-value, which
  recent toolchain snapshots now issue a warning for
  in `Decodable` types.

This PR moves the `master` branch up to require the
`swift-DEVELOPMENT-SNAPSHOT-2020-04-19-a` development
snapshot toolchain.

Author: allevato

Package.resolved

@@ -21,8 +21,14 @@ let package = Package(
     .library(name: "SwiftFormatConfiguration", targets: ["SwiftFormatConfiguration"]),
   ],
   dependencies: [
-    .package(url: "https://github.com/apple/swift-syntax", from: "0.50200.0"),
-    .package(url: "https://github.com/apple/swift-argument-parser.git", .upToNextMinor(from: "0.0.4")),
+    .package(
+      url: "https://github.com/apple/swift-syntax",
+      .revision("swift-DEVELOPMENT-SNAPSHOT-2020-04-19-a")
+    ),
+    .package(
+      url: "https://github.com/apple/swift-argument-parser.git",
+      .upToNextMinor(from: "0.0.4")
+    ),
   ],
   targets: [
     .target(

Package.swift

@@ -25,7 +25,7 @@ is also expressed in the `SwiftSyntax` dependency in
 
 | Xcode Release | Swift Version                           | `swift-format` Branch |
 |:-------------:|:---------------------------------------:|:----------------------|
-| –             | swift-5.2-RELEASE                       | `master`              |
+| –             | swift-DEVELOPMENT-SNAPSHOT-2020-04-19-a | `master`              |
 | Xcode 11.4    | Swift 5.2                               | `swift-5.2-branch`    |
 | Xcode 11.0    | Swift 5.1                               | `swift-5.1-branch`    |
 
@@ -46,12 +46,14 @@ version of Swift or on a developer snapshot. Changes committed to `master`
 that are compatible with the latest release branch will be cherry-picked into
 that branch.
 
-To test that the formatter was built succesfully and is compatible with your swift toolchain, you can run the following command:
+To test that the formatter was built succesfully and is compatible with your
+Swift toolchain, you can run the following command:
 
 ```
 swift test --parallel
 ```
-We recommend using the `--parallel` flag to speed up the test run since there are a large number of tests.
+We recommend using the `--parallel` flag to speed up the test run since there
+are a large number of tests.
 
 ## Command Line Usage
 

README.md

@@ -228,23 +228,6 @@ public struct Configuration: Codable, Equatable {
   }
 }
 
-/// Configuration for the NoPlaygroundLiterals rule.
-public struct NoPlaygroundLiteralsConfiguration: Codable, Equatable {
-  public enum ResolveBehavior: String, Codable {
-    /// If not sure, use `UIColor` to replace `#colorLiteral`.
-    case useUIColor
-
-    /// If not sure, use `NSColor` to replace `#colorLiteral`.
-    case useNSColor
-
-    /// If not sure, raise an error.
-    case error
-  }
-
-  /// Resolution behavior to use when encountering an ambiguous `#colorLiteral`.
-  public let resolveAmbiguousColor: ResolveBehavior = .useUIColor
-}
-
 /// Configuration for the `FileScopedDeclarationPrivacy` rule.
 public struct FileScopedDeclarationPrivacyConfiguration: Codable, Equatable {
   public enum AccessLevel: String, Codable {

Sources/SwiftFormatConfiguration/Configuration.swift

@@ -580,7 +580,20 @@ fileprivate final class TokenStreamCreator: SyntaxVisitor {
     let catchPrecedingBreak = config.lineBreakBeforeControlFlowKeywords
       ? Token.break(.same, newlines: .soft) : Token.space
     before(node.catchKeyword, tokens: catchPrecedingBreak)
-    before(node.pattern?.firstToken, tokens: .space)
+
+    if let catchItems = node.catchItems {
+      // If there are multiple items in the `catch` clause, wrap each in open/close breaks so that
+      // their internal breaks stack correctly. Otherwise, if there is only a single clause, use the
+      // old (pre-SE-0276) behavior (a fixed space after the `catch` keyword).
+      if catchItems.count > 1 {
+        for catchItem in catchItems {
+          before(catchItem.firstToken, tokens: .break(.open(kind: .continuation)))
+          after(catchItem.lastToken, tokens: .break(.close(mustBreak: false), size: 0))
+        }
+      } else {
+        before(node.catchItems?.firstToken, tokens: .space)
+      }
+    }
 
     arrangeBracesAndContents(of: node.body, contentsKeyPath: \.statements)
 
@@ -1499,7 +1512,9 @@ fileprivate final class TokenStreamCreator: SyntaxVisitor {
     //     }
     //
     let wherePrecedingBreak: Token
-    if !config.lineBreakBeforeControlFlowKeywords, let parent = node.parent, parent.is(CatchClauseSyntax.self) {
+    if !config.lineBreakBeforeControlFlowKeywords,
+      let parent = node.parent, parent.is(CatchItemSyntax.self)
+    {
       wherePrecedingBreak = .break(.continue)
     } else {
       wherePrecedingBreak = .break(.same)
@@ -2100,21 +2115,6 @@ fileprivate final class TokenStreamCreator: SyntaxVisitor {
       needsBreakBeforeWhereClause = true
     }
 
-    // TODO: These properties will likely go away in a future version since the parser no longer
-    // reads the `vjp:` and `jvp:` arguments to `@differentiable`.
-    if let vjp = node.maybeVJP {
-      before(vjp.firstToken, tokens: .open)
-      after(vjp.lastToken, tokens: .close)
-      after(vjp.trailingComma, tokens: .break(.same))
-      needsBreakBeforeWhereClause = true
-    }
-    if let jvp = node.maybeJVP {
-      before(jvp.firstToken, tokens: .open)
-      after(jvp.lastToken, tokens: .close)
-      after(jvp.trailingComma, tokens: .break(.same))
-      needsBreakBeforeWhereClause = true
-    }
-
     if let whereClause = node.whereClause {
       if needsBreakBeforeWhereClause {
         before(whereClause.firstToken, tokens: .break(.same))
@@ -2125,24 +2125,13 @@ fileprivate final class TokenStreamCreator: SyntaxVisitor {
     return .visitChildren
   }
 
-  override func visit(_ node: DifferentiableAttributeFuncSpecifierSyntax)
-    -> SyntaxVisitorContinueKind
-  {
-    // This node encapsulates the `vjp:` or `jvp:` label and decl name in a `@differentiable`
-    // attribute.
-    // TODO: This node will likely go away in a future version since the parser no longer reads the
-    // `vjp:` and `jvp:` arguments to `@differentiable`.
-    after(node.colon, tokens: .break(.continue, newlines: .elective(ignoresDiscretionary: true)))
-    return .visitChildren
-  }
-
-  override func visit(_ node: DifferentiationParamsSyntax) -> SyntaxVisitorContinueKind {
+  override func visit(_ node: DifferentiabilityParamsSyntax) -> SyntaxVisitorContinueKind {
     after(node.leftParen, tokens: .break(.open, size: 0), .open)
     before(node.rightParen, tokens: .break(.close, size: 0), .close)
     return .visitChildren
   }
 
-  override func visit(_ node: DifferentiationParamSyntax) -> SyntaxVisitorContinueKind {
+  override func visit(_ node: DifferentiabilityParamSyntax) -> SyntaxVisitorContinueKind {
     after(node.trailingComma, tokens: .break(.same))
     return .visitChildren
   }
@@ -2168,7 +2157,7 @@ fileprivate final class TokenStreamCreator: SyntaxVisitor {
     }
   #endif
 
-  override func visit(_ node: DifferentiationParamsClauseSyntax) -> SyntaxVisitorContinueKind {
+  override func visit(_ node: DifferentiabilityParamsClauseSyntax) -> SyntaxVisitorContinueKind {
     // This node encapsulates the `wrt:` label and value/variable in a `@differentiable`,
     // `@derivative`, or `@transpose` attribute.
     after(node.colon, tokens: .break(.continue, newlines: .elective(ignoresDiscretionary: true)))

Sources/SwiftFormatPrettyPrint/TokenStreamCreator.swift

@@ -173,4 +173,62 @@ final class TryCatchTests: PrettyPrintTestCase {
       """
     assertPrettyPrintEqual(input: input, expected: input + "\n", linelength: 45)
   }
+
+  func testMultipleCatchItems() {
+    let input =
+      """
+      do { try thisMightFail() } catch error1, error2 { print("Nope") }
+      do { try thisMightFail() } catch longErrorType, error2 { print("Nope") }
+      do { try thisMightFail() } catch longErrorTypeName, longErrorType2(let someLongVariable) { print("Nope") }
+      do { try thisMightFail() } catch longErrorTypeName, longErrorType2 as SomeLongErrorType { print("Nope") }
+      do { try thisMightFail() } catch longErrorName where someCondition, longErrorType2 { print("Nope") }
+      do { try thisMightFail() } catch longErrorTypeName, longErrorType2 as SomeLongErrorType where someCondition, longErrorType3 { print("Nope") }
+      """
+
+    let expected =
+      """
+      do {
+        try thisMightFail()
+      } catch error1, error2 {
+        print("Nope")
+      }
+      do {
+        try thisMightFail()
+      } catch longErrorType,
+        error2
+      { print("Nope") }
+      do {
+        try thisMightFail()
+      } catch
+        longErrorTypeName,
+        longErrorType2(
+          let someLongVariable)
+      { print("Nope") }
+      do {
+        try thisMightFail()
+      } catch
+        longErrorTypeName,
+        longErrorType2
+          as SomeLongErrorType
+      { print("Nope") }
+      do {
+        try thisMightFail()
+      } catch longErrorName
+        where someCondition,
+        longErrorType2
+      { print("Nope") }
+      do {
+        try thisMightFail()
+      } catch
+        longErrorTypeName,
+        longErrorType2
+          as SomeLongErrorType
+          where someCondition,
+        longErrorType3
+      { print("Nope") }
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 25)
+  }
 }

Tests/SwiftFormatPrettyPrintTests/TryCatchTests.swift

@@ -747,6 +747,7 @@ extension TryCatchTests {
         ("testCatchWhere_noBreakBeforeCatch", testCatchWhere_noBreakBeforeCatch),
         ("testDoTryCatch_breakBeforeCatch", testDoTryCatch_breakBeforeCatch),
         ("testDoTryCatch_noBreakBeforeCatch", testDoTryCatch_noBreakBeforeCatch),
+        ("testMultipleCatchItems", testMultipleCatchItems),
         ("testNestedDo", testNestedDo),
     ]
 }