From 485518faef04df4e80bfdedfeec01c586a4419f7 Mon Sep 17 00:00:00 2001
From: Marcelo Fabri <marcelofabrimf@gmail.com>
Date: Wed, 30 Nov 2016 19:02:12 -0200
Subject: [PATCH] TrailingCommaRule only triggers when multi-line

Fixes #910 and #911
---
 CHANGELOG.md                                  |  6 +++++-
 .../Rules/TrailingCommaRule.swift             | 10 +++++++++-
 Tests/SwiftLintFramework/RulesTests.swift     | 19 +++++++++++++------
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4ae3881f39..3abb09208b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,11 @@
 
 ##### Enhancements
 
-* None.
+* `TrailingCommaRule` now only triggers when a declaration is multi-line
+  when using `mandatory_comma: true`.  
+  [Marcelo Fabri](https://github.com/marcelofabri)
+  [#910](https://github.com/realm/SwiftLint/issues/910)
+  [#911](https://github.com/realm/SwiftLint/issues/911)
 
 ##### Bug Fixes
 
diff --git a/Source/SwiftLintFramework/Rules/TrailingCommaRule.swift b/Source/SwiftLintFramework/Rules/TrailingCommaRule.swift
index 85770d3e03..2dacfea02d 100644
--- a/Source/SwiftLintFramework/Rules/TrailingCommaRule.swift
+++ b/Source/SwiftLintFramework/Rules/TrailingCommaRule.swift
@@ -22,7 +22,8 @@ public struct TrailingCommaRule: ASTRule, ConfigurationProviderRule {
             "let foo = [1, 2, 3]\n",
             "let foo = []\n",
             "let foo = [:]\n",
-            "let foo = [1: 2, 2: 3]\n"
+            "let foo = [1: 2, 2: 3]\n",
+            "let foo = [Void]()\n"
         ],
         triggeringExamples: [
             "let foo = [1, 2, 3↓,]\n",
@@ -61,6 +62,13 @@ public struct TrailingCommaRule: ASTRule, ConfigurationProviderRule {
             return []
         }
 
+        if let (startLine, _) =  file.contents.lineAndCharacterForByteOffset(bodyOffset),
+            (endLine, _) =  file.contents.lineAndCharacterForByteOffset(lastPosition)
+            where configuration.mandatoryComma && startLine == endLine {
+            // shouldn't trigger if mandatory comma style and is a single-line declaration 
+            return []
+        }
+
         let length = bodyLength + bodyOffset - lastPosition
         let contentsAfterLastElement = file.contents
             .substringWithByteRange(start: lastPosition, length: length) ?? ""
diff --git a/Tests/SwiftLintFramework/RulesTests.swift b/Tests/SwiftLintFramework/RulesTests.swift
index a98c5a3128..56be491032 100644
--- a/Tests/SwiftLintFramework/RulesTests.swift
+++ b/Tests/SwiftLintFramework/RulesTests.swift
@@ -265,14 +265,21 @@ class RulesTests: XCTestCase {
                 "let foo = [1, 2, 3, ]\n",
                 "let foo = [1, 2, 3   ,]\n",
                 "let foo = [1: 2, 2: 3, ]\n",
-                "struct Bar {\n let foo = [1: 2, 2: 3,]\n}\n"
+                "struct Bar {\n let foo = [1: 2, 2: 3,]\n}\n",
+                "let foo = [Void]()\n",
+                "let foo = [(Void, Void)]()\n",
+                "let foo = [1, 2, 3]\n",
+                "let foo = [1: 2, 2: 3]\n",
+                "let foo = [1: 2, 2: 3   ]\n",
+                "struct Bar {\n let foo = [1: 2, 2: 3]\n}\n",
+                "let foo = [1, 2, 3] + [4, 5, 6]\n"
             ],
             triggeringExamples: [
-                "let foo = [1, 2, 3↓]\n",
-                "let foo = [1: 2, 2: 3↓]\n",
-                "let foo = [1: 2, 2: 3↓   ]\n",
-                "struct Bar {\n let foo = [1: 2, 2: 3↓]\n}\n",
-                "let foo = [1, 2, 3↓] + [4, 5, 6↓]\n"
+                "let foo = [1, 2,\n 3↓]\n",
+                "let foo = [1: 2,\n 2: 3↓]\n",
+                "let foo = [1: 2,\n 2: 3↓   ]\n",
+                "struct Bar {\n let foo = [1: 2,\n 2: 3↓]\n}\n",
+                "let foo = [1, 2,\n 3↓] + [4,\n 5, 6↓]\n"
             ]
         )