Fix false positive in empty_string rule with multiline literals

Fixes #3100
realm · Feb 10, 2020 · 38eb3ed · 38eb3ed
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -95,6 +95,11 @@
   [Marcelo Fabri](https://github.com/marcelofabri)
   [#3079](https://github.com/realm/SwiftLint/issues/3079)
 
+* Fix false positive in `empty_string` rule when using multiline string
+  literals.  
+  [Marcelo Fabri](https://github.com/marcelofabri)
+  [#3100](https://github.com/realm/SwiftLint/issues/3100)
+
 ## 0.38.2: Machine Repair Manual
 
 #### Breaking

diff --git a/Source/SwiftLintFramework/Rules/Performance/EmptyStringRule.swift b/Source/SwiftLintFramework/Rules/Performance/EmptyStringRule.swift
@@ -12,7 +12,8 @@ public struct EmptyStringRule: ConfigurationProviderRule, OptInRule, AutomaticTe
         kind: .performance,
         nonTriggeringExamples: [
             Example("myString.isEmpty"),
-            Example("!myString.isEmpty")
+            Example("!myString.isEmpty"),
+            Example("\"\"\"\nfoo==\n\"\"\"")
         ],
         triggeringExamples: [
             Example("myString↓ == \"\""),
@@ -22,10 +23,16 @@ public struct EmptyStringRule: ConfigurationProviderRule, OptInRule, AutomaticTe
 
     public func validate(file: SwiftLintFile) -> [StyleViolation] {
         let pattern = "\\b\\s*(==|!=)\\s*\"\""
-        return file.match(pattern: pattern, with: [.string]).map {
-            StyleViolation(ruleDescription: type(of: self).description,
-                           severity: configuration.severity,
-                           location: Location(file: file, characterOffset: $0.location))
+        return file.match(pattern: pattern, with: [.string]).compactMap { range in
+            guard let byteRange = file.stringView.NSRangeToByteRange(NSRange(location: range.location, length: 1)),
+                case let kinds = file.syntaxMap.kinds(inByteRange: byteRange),
+                kinds.isEmpty else {
+                    return nil
+            }
+
+            return StyleViolation(ruleDescription: type(of: self).description,
+                                  severity: configuration.severity,
+                                  location: Location(file: file, characterOffset: range.location))
         }
     }
 }