Merge pull request swiftlang#222 from dabelknap/collection-literal-whitespace

Demote CollectionLiteralWhitespace to a lint rule

Author: allevato

Diff for: Sources/SwiftFormat/PopulatePipeline.swift

@@ -31,12 +31,6 @@ func populate(_ pipeline: Pipeline) {
       MemberDeclBlockSyntax.self
   )
 
-  pipeline.addFormatter(
-    CollectionLiteralWhitespace.self,
-    for:
-      TokenSyntax.self
-  )
-
   pipeline.addFormatter(
     DoNotUseSemicolons.self,
     for:
@@ -268,6 +262,12 @@ func populate(_ pipeline: Pipeline) {
       TokenSyntax.self
   )
 
+  pipeline.addLinter(
+    CollectionLiteralWhitespace.self,
+    for:
+      TokenSyntax.self
+  )
+
   pipeline.addLinter(
     ColonWhitespace.self,
     for:

Diff for: Sources/SwiftFormatRules/CollectionLiteralWhitespace.swift

@@ -20,27 +20,24 @@ import SwiftSyntax
 ///       after the opening delimiter, or any spaces before the closing delimiter, a lint
 ///       error is raised.
 ///
-/// Format: Extraneous spaces at the beginning and end of collection literals will be removed.
-///
 /// - SeeAlso: https://google.github.io/swift#horizontal-whitespace
-public final class CollectionLiteralWhitespace: SyntaxFormatRule {
-  public override func visit(_ token: TokenSyntax) -> Syntax {
+public final class CollectionLiteralWhitespace: SyntaxLintRule {
+  public override func visit(_ token: TokenSyntax) {
     // Ensure we have an adjacent token on the same line
-    guard let next = token.nextToken else { return token }
-    if next.leadingTrivia.containsNewlines { return token }
+    guard let next = token.nextToken else { return }
+    if next.leadingTrivia.containsNewlines { return }
 
     // If either this current token is a left delimiter, or the next token
     // is a right delimiter, then remove spaces from our trailing trivia.
     if token.tokenKind.isLeftBalancedDelimiter && token.trailingTrivia.containsSpaces {
       diagnose(.noSpacesAfter(token), on: token)
-      return token.withTrailingTrivia(token.trailingTrivia.withoutSpaces())
+      return
     }
 
     if next.tokenKind.isRightBalancedDelimiter && token.trailingTrivia.containsSpaces {
       diagnose(.noSpacesBefore(next), on: next)
-      return token.withTrailingTrivia(token.trailingTrivia.withoutSpaces())
+      return
     }
-    return token
   }
 }
 

Diff for: Tests/SwiftFormatRulesTests/CollectionLiteralWhitespaceTests.swift

@@ -6,34 +6,53 @@ import SwiftSyntax
 
 public class CollectionLiteralWhitespaceTests: DiagnosingTestCase {
   public func testInvalidCollectionLiteralWhitespace() {
-    XCTAssertFormatting(
-      CollectionLiteralWhitespace.self,
-      input: """
-             func a( x: Int ) {
-               print( [ x ] )
-               if ( x == 0 ) {
-                 var arr = [ Int ]()
-                 arr.append(x )
-                 print( arr)
-               }
-             }
-             """,
-      expected: """
-                func a(x: Int) {
-                  print([x])
-                  if (x == 0) {
-                    var arr = [Int]()
-                    arr.append(x)
-                    print(arr)
-                  }
-                }
-                """)
+    let input =
+      """
+      func a( x: Int ) {
+        print( [ x ] )
+        if ( x == 0 ) {
+          var arr = [ Int ]()
+          arr.append(x )
+          print( arr)
+        }
+      }
+      """
+
+    performLint(CollectionLiteralWhitespace.self, input: input)
+
+    let leftParen = SyntaxFactory.makeLeftParenToken()
+    let rightParen = SyntaxFactory.makeRightParenToken()
+    let leftSquare = SyntaxFactory.makeLeftSquareBracketToken()
+    let rightSquare = SyntaxFactory.makeRightSquareBracketToken()
+
+    // func a( x: Int ) {
+    XCTAssertDiagnosed(.noSpacesAfter(leftParen))
+    XCTAssertDiagnosed(.noSpacesBefore(rightParen))
+
+    // print( [ x ] )
+    XCTAssertDiagnosed(.noSpacesAfter(leftParen))
+    XCTAssertDiagnosed(.noSpacesAfter(leftSquare))
+    XCTAssertDiagnosed(.noSpacesBefore(rightSquare))
+    XCTAssertDiagnosed(.noSpacesBefore(rightParen))
+
+    // if ( x == 0 ) {
+    XCTAssertDiagnosed(.noSpacesAfter(leftParen))
+    XCTAssertDiagnosed(.noSpacesBefore(rightParen))
+
+    // var arr = [ Int ]()
+    XCTAssertDiagnosed(.noSpacesAfter(leftSquare))
+    XCTAssertDiagnosed(.noSpacesBefore(rightSquare))
+
+    // arr.append(x )
+    XCTAssertDiagnosed(.noSpacesBefore(rightParen))
+
+    // print( arr)
+    XCTAssertDiagnosed(.noSpacesAfter(leftParen))
   }
 
 #if !os(macOS)
   static let allTests = [
     CollectionLiteralWhitespaceTests.testInvalidCollectionLiteralWhitespace,
   ]
 #endif
-
 }