Add new file_content_type for PreviewProvider subclasses for SwiftUI …

…support Fixes #2860.
realm · Feb 1, 2020 · 432b418 · 432b418
1 parent ed54fd6
commit 432b418
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -19,6 +19,11 @@
   grouping it with initializers.  
   [Steven Magdy](https://github.com/StevenMagdy)
 
+* Add case `preview_provider` to the order list of `file_types_order` to fix
+  an issue with false positives for `PreviewProvider` subclasses in SwiftUI.  
+  [Cihat Gündüz](https://github.com/Jeehut)
+  [#2860](https://github.com/realm/SwiftLint/issues/2860)
+
 #### Bug Fixes
 
 * Fix `discarded_notification_center_observer` false positives when

diff --git a/Source/SwiftLintFramework/Rules/RuleConfigurations/FileTypesOrderConfiguration.swift b/Source/SwiftLintFramework/Rules/RuleConfigurations/FileTypesOrderConfiguration.swift
@@ -2,14 +2,16 @@ enum FileType: String {
     case supportingType = "supporting_type"
     case mainType = "main_type"
     case `extension` = "extension"
+    case previewProvider = "preview_provider"
 }
 
 public struct FileTypesOrderConfiguration: RuleConfiguration, Equatable {
     private(set) var severityConfiguration = SeverityConfiguration(.warning)
     private(set) var order: [[FileType]] = [
         [.supportingType],
         [.mainType],
-        [.extension]
+        [.extension],
+        [.previewProvider]
     ]
 
     public var consoleDescription: String {

diff --git a/Source/SwiftLintFramework/Rules/Style/FileTypesOrderRule.swift b/Source/SwiftLintFramework/Rules/Style/FileTypesOrderRule.swift
@@ -32,6 +32,8 @@ public struct FileTypesOrderRule: ConfigurationProviderRule, OptInRule {
             mainTypeSubstructure: mainTypeSubstructure
         )
 
+        let previewProviderSubstructures = self.previewProviderSubstructures(in: file)
+
         let mainTypeOffset: [FileTypeOffset] = [(.mainType, mainTypeSubstuctureOffset)]
         let extensionOffsets: [FileTypeOffset] = extensionsSubstructures.compactMap { substructure in
             guard let offset = substructure.offset else { return nil }
@@ -43,10 +45,14 @@ public struct FileTypesOrderRule: ConfigurationProviderRule, OptInRule {
             return (.supportingType, offset)
         }
 
-        let orderedFileTypeOffsets = (mainTypeOffset + extensionOffsets + supportingTypeOffsets).sorted { lhs, rhs in
-            return lhs.offset < rhs.offset
+        let previewProviderOffsets: [FileTypeOffset] = previewProviderSubstructures.compactMap { substructure in
+            guard let offset = substructure.offset else { return nil }
+            return (.previewProvider, offset)
         }
 
+        let allOffsets: [FileTypeOffset] = mainTypeOffset + extensionOffsets + supportingTypeOffsets + previewProviderOffsets
+        let orderedFileTypeOffsets = allOffsets.sorted { lhs, rhs in lhs.offset < rhs.offset }
+
         var violations =  [StyleViolation]()
 
         var lastMatchingIndex = -1
@@ -106,12 +112,19 @@ public struct FileTypesOrderRule: ConfigurationProviderRule, OptInRule {
         let dict = file.structureDictionary
         return dict.substructure.filter { substructure in
             guard let declarationKind = substructure.declarationKind else { return false }
+            guard !substructure.inheritedTypes.contains("PreviewProvider") else { return false }
 
             return substructure.offset != mainTypeSubstructure.offset &&
                 supportingTypeKinds.contains(declarationKind)
         }
     }
 
+    private func previewProviderSubstructures(in file: SwiftLintFile) -> [SourceKittenDictionary] {
+        return file.structureDictionary.substructure.filter { substructure in
+            return substructure.inheritedTypes.contains("PreviewProvider")
+        }
+    }
+
     private func mainTypeSubstructure(in file: SwiftLintFile) -> SourceKittenDictionary? {
         let dict = file.structureDictionary
 
@@ -133,6 +146,8 @@ public struct FileTypesOrderRule: ConfigurationProviderRule, OptInRule {
 
         let priorityKindSubstructures = dict.substructure.filter { substructure in
             guard let kind = substructure.declarationKind else { return false }
+            guard !substructure.inheritedTypes.contains("PreviewProvider") else { return false }
+
             return priorityKinds.contains(kind)
         }
 

diff --git a/Source/SwiftLintFramework/Rules/Style/FileTypesOrderRuleExamples.swift b/Source/SwiftLintFramework/Rules/Style/FileTypesOrderRuleExamples.swift
@@ -130,6 +130,17 @@ internal struct FileTypesOrderRuleExamples {
         extension Foo {}
         extension Bar {
         }
+        """,
+        """
+        struct ContentView: View {
+            var body: some View {
+                Text("Hello, World!")
+            }
+        }
+
+        struct ContentView_Previews: PreviewProvider {
+            static var previews: some View { ContentView() }
+        }
         """
     ]
 
@@ -198,6 +209,19 @@ internal struct FileTypesOrderRuleExamples {
                 return UITableViewCell()
             }
         }
+        """,
+        """
+        // Preview Provider
+        ↓struct ContentView_Previews: PreviewProvider {
+            static var previews: some View { ContentView() }
+        }
+
+        // Main Type
+        struct ContentView: View {
+            var body: some View {
+                Text("Hello, World!")
+            }
+        }
         """
     ]
 }
diff --git a/Tests/SwiftLintFrameworkTests/FileTypesOrderRuleTests.swift b/Tests/SwiftLintFrameworkTests/FileTypesOrderRuleTests.swift
@@ -9,7 +9,7 @@ class FileTypesOrderRuleTests: XCTestCase {
         verifyRule(FileTypesOrderRule.description)
     }
 
-    func testFileTypesOrderReversedOrder() {
+func testFileTypesOrderReversedOrder() {
         // Test with reversed `order` entries
         let nonTriggeringExamples = [
             FileTypesOrderRuleExamples.defaultOrderParts.reversed().joined(separator: "\n\n")
@@ -49,6 +49,17 @@ class FileTypesOrderRuleTests: XCTestCase {
             protocol TestViewControllerDelegate {
                 func didPressTrackedButton()
             }
+            """,
+            """
+            ↓struct ContentView: View {
+               var body: some View {
+                   Text("Hello, World!")
+               }
+            }
+
+            struct ContentView_Previews: PreviewProvider {
+               static var previews: some View { ContentView() }
+            }
             """
         ]
 
@@ -59,7 +70,7 @@ class FileTypesOrderRuleTests: XCTestCase {
         verifyRule(
             reversedOrderDescription,
             ruleConfiguration: [
-                "order": ["extension", "main_type", "supporting_type"]
+                "order": ["preview_provider", "extension", "main_type", "supporting_type"]
             ]
         )
     }
@@ -125,7 +136,7 @@ class FileTypesOrderRuleTests: XCTestCase {
         verifyRule(
             groupedOrderDescription,
             ruleConfiguration: [
-                "order": ["main_type", ["extension", "supporting_type"]]
+                "order": ["main_type", ["extension", "supporting_type"], "preview_provider"]
             ]
         )
     }