Issue realm#3167: Fixes false positives for multiline_parameters_brac…

…kets and multiline_arguments_brackets

Source/SwiftLintFramework/Extensions/SourceKittenDictionary+Swiftlint.swift

@@ -41,4 +41,19 @@ extension SourceKittenDictionary {
         parse(self)
         return results
     }
+
+    /// Return the string content of this structure in the given file.
+    /// - Parameter file: File this structure occurs in
+    /// - Returns: The content of the file which this `SourceKittenDictionary` structure represents
+    func content(in file: SwiftLintFile) -> String? {
+        guard
+            let byteRange = self.byteRange,
+            let range = file.stringView.byteRangeToNSRange(byteRange)
+        else {
+            return nil
+        }
+
+        let body = file.stringView.nsString.substring(with: range)
+        return String(body)
+    }
 }

Source/SwiftLintFramework/Extensions/String+SwiftLint.swift

@@ -91,4 +91,13 @@ extension String {
         }
         return false
     }
+
+    /// Count the number of occurrences of the given character in `self`
+    /// - Parameter character: Character to count
+    /// - Returns: Number of times `character` occurs in `self`
+    public func countOccurrences(of character: Character) -> Int {
+        return self.reduce(0, {
+            $1 == character ? $0 + 1 : $0
+        })
+    }
 }

Source/SwiftLintFramework/Rules/Style/MultilineArgumentsBracketsRule.swift

@@ -44,7 +44,30 @@ public struct MultilineArgumentsBracketsRule: ASTRule, OptInRule, ConfigurationP
             AlertViewModel.AlertAction(title: "some title", style: .default) {
                 AlertManager.shared.presentNextDebugAlert()
             }
-            """)
+            """),
+            Example("""
+            public final class Logger {
+                public static let shared = Logger(outputs: [
+                    OSLoggerOutput(),
+                    ErrorLoggerOutput()
+                ])
+            }
+            """),
+            Example("""
+            let errors = try self.download([
+                (description: description, priority: priority),
+            ])
+            """),
+            Example("""
+            return SignalProducer({ observer, _ in
+                observer.sendCompleted()
+            }).onMainQueue()
+            """),
+            Example("""
+            SomeType(a: [
+                1, 2, 3
+            ], b: [1, 2])
+            """),
         ],
         triggeringExamples: [
             Example("""
@@ -71,6 +94,12 @@ public struct MultilineArgumentsBracketsRule: ASTRule, OptInRule, ConfigurationP
                     x: 5,
                     y: 7
             )↓)
+            """),
+            Example("""
+            SomeOtherType(↓a: [
+                    1, 2, 3
+                ],
+                b: "two"↓)
             """)
         ]
     )
@@ -86,8 +115,19 @@ public struct MultilineArgumentsBracketsRule: ASTRule, OptInRule, ConfigurationP
             return []
         }
 
-        let body = file.contents.substring(from: range.location, length: range.length)
-        let isMultiline = body.contains("\n")
+        let callBody = file.contents.substring(from: range.location, length: range.length)
+
+        let parameters = dictionary.substructure.filter {
+            // Argument expression types that can contain newlines
+            [.argument, .array, .dictionary, .closure].contains($0.expressionKind)
+        }
+        let parameterBodies = parameters.compactMap { $0.content(in: file) }
+        let parametersNewlineCount = parameterBodies.map { body in
+            return body.countOccurrences(of: "\n")
+        }.reduce(0, +)
+        let callNewlineCount = callBody.countOccurrences(of: "\n")
+        let isMultiline = callNewlineCount > parametersNewlineCount
+
         guard isMultiline else {
             return []
         }
@@ -96,11 +136,11 @@ public struct MultilineArgumentsBracketsRule: ASTRule, OptInRule, ConfigurationP
         let expectedBodyEndRegex = regex("\\n[ \\t]*\\z")
 
         var violatingByteOffsets = [ByteCount]()
-        if expectedBodyBeginRegex.firstMatch(in: body, options: [], range: body.fullNSRange) == nil {
+        if expectedBodyBeginRegex.firstMatch(in: callBody, options: [], range: callBody.fullNSRange) == nil {
             violatingByteOffsets.append(bodyRange.location)
         }
 
-        if expectedBodyEndRegex.firstMatch(in: body, options: [], range: body.fullNSRange) == nil {
+        if expectedBodyEndRegex.firstMatch(in: callBody, options: [], range: callBody.fullNSRange) == nil {
             violatingByteOffsets.append(bodyRange.upperBound)
         }
 

Source/SwiftLintFramework/Rules/Style/MultilineParametersBracketsRule.swift

@@ -50,6 +50,11 @@ public struct MultilineParametersBracketsRule: OptInRule, ConfigurationProviderR
             """),
             Example("""
             func foo<T>(param1: T, param2: String, param3: String) -> T { /* some code */ }
+            """),
+            Example("""
+                func foo(a: [Int] = [
+                    1
+                ])
             """)
         ],
         triggeringExamples: [
@@ -106,9 +111,14 @@ public struct MultilineParametersBracketsRule: OptInRule, ConfigurationProviderR
                 return []
             }
 
-            let isMultiline = functionName.contains("\n")
-
             let parameters = substructure.substructure.filter { $0.declarationKind == .varParameter }
+            let parameterBodies = parameters.compactMap { $0.content(in: file) }
+            let parametersNewlineCount = parameterBodies.map { body in
+                return body.countOccurrences(of: "\n")
+            }.reduce(0, +)
+            let declarationNewlineCount = functionName.countOccurrences(of: "\n")
+            let isMultiline = declarationNewlineCount > parametersNewlineCount
+
             if isMultiline && !parameters.isEmpty {
                 if let openingBracketViolation = openingBracketViolation(parameters: parameters, file: file) {
                     violations.append(openingBracketViolation)

Tests/SwiftLintFrameworkTests/ExtendedStringTests.swift

@@ -0,0 +1,16 @@
+//
+//  ExtendedStringTests.swift
+//  SwiftLintFrameworkTests
+//
+//  Created by Noah Gilmore on 4/5/20.
+//
+
+import XCTest
+
+class ExtendedStringTests: XCTestCase {
+    func testCountOccurrences() {
+        XCTAssertEqual("aabbabaaba".countOccurrences(of: "a"), 6)
+        XCTAssertEqual("".countOccurrences(of: "a"), 0)
+        XCTAssertEqual("\n\n".countOccurrences(of: "\n"), 2)
+    }
+}