Fixes an issue with string comparison in ChartData for finding a dataset by its label (Fixes #4274)

ChartData::getDataSetByLabel has a bug where the string comparison is checking the same string against itself due to the functions parameter having the same name as a variable within the closures scope. This change renames the variable to fix the issue.

ChartDataTests.swift

@@ -0,0 +1,69 @@
+//
+//  ChartDataTests.swift
+//  ChartsTests
+//
+//  Created by Peter Kaminski on 1/23/20.
+//
+
+import XCTest
+@testable import Charts
+
+class ChartDataTests: XCTestCase {
+    
+    var data: ScatterChartData!
+
+    private enum SetLabels {
+        static let one = "label1"
+        static let two = "label2"
+        static let three = "label3"
+        static let badLabel = "Bad label"
+    }
+    
+    override func setUp() {
+        super.setUp()
+        
+        let setCount = 5
+        let range: UInt32 = 32
+        let values1 = (0..<setCount).map { (i) -> ChartDataEntry in
+            let val = Double(arc4random_uniform(range) + 3)
+            return ChartDataEntry(x: Double(i), y: val)
+        }
+        let values2 = (0..<setCount).map { (i) -> ChartDataEntry in
+            let val = Double(arc4random_uniform(range) + 3)
+            return ChartDataEntry(x: Double(i), y: val)
+        }
+        let values3 = (0..<setCount).map { (i) -> ChartDataEntry in
+            let val = Double(arc4random_uniform(range) + 3)
+            return ChartDataEntry(x: Double(i), y: val)
+        }
+        
+        let set1 = ScatterChartDataSet(entries: values1, label: SetLabels.one)
+        let set2 = ScatterChartDataSet(entries: values2, label: SetLabels.two)
+        let set3 = ScatterChartDataSet(entries: values3, label: SetLabels.three)
+        
+        data = ScatterChartData(dataSets: [set1, set2, set3])
+    }
+    
+    func testGetDataSetByLabelCaseSensitive() {
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.one, ignorecase: false)?.label == SetLabels.one)
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.two, ignorecase: false)?.label == SetLabels.two)
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.three, ignorecase: false)?.label == SetLabels.three)
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.one.uppercased(), ignorecase: false) == nil)
+    }
+    
+    func testGetDataSetByLabelIgnoreCase() {
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.one, ignorecase: true)?.label == SetLabels.one)
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.two, ignorecase: true)?.label == SetLabels.two)
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.three, ignorecase: true)?.label == SetLabels.three)
+        
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.one.uppercased(), ignorecase: true)?.label == SetLabels.one)
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.two.uppercased(), ignorecase: true)?.label == SetLabels.two)
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.three.uppercased(), ignorecase: true)?.label == SetLabels.three)
+    }
+    
+    func testGetDataSetByLabelNilWithBadLabel() {
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.badLabel, ignorecase: true) == nil)
+        XCTAssertTrue(data.getDataSetByLabel(SetLabels.badLabel, ignorecase: false) == nil)
+    }
+}
+

Charts.xcodeproj/project.pbxproj

@@ -117,6 +117,7 @@
 		B6DCC229615EFE706F64A37D /* LineScatterCandleRadarRenderer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 923206233CA89FD03565FF87 /* LineScatterCandleRadarRenderer.swift */; };
 		B85DEB06B4C1AFFC8A0E3295 /* CircleShapeRenderer.swift in Sources */ = {isa = PBXBuildFile; fileRef = ECE1B1623D3AF69CECAE8562 /* CircleShapeRenderer.swift */; };
 		BEFD9518F3A74ACF8FA33308 /* Charts.h in Headers */ = {isa = PBXBuildFile; fileRef = 4F9922F0641F7955DC6CD324 /* Charts.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		C03E6D8123DAAB2600083010 /* ChartDataTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C03E6D8023DAAB2600083010 /* ChartDataTests.swift */; };
 		C04D269AD4A373FD2B621C43 /* LineChartData.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C978F31F23C7D21197DC2A1 /* LineChartData.swift */; };
 		C09E91F67A4AC43C277E7D82 /* BubbleChartDataEntry.swift in Sources */ = {isa = PBXBuildFile; fileRef = DD8ED233775EEC31243A6919 /* BubbleChartDataEntry.swift */; };
 		C20A62D8CB9120523D5FB650 /* LegendEntry.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9E7C673B9ED4340F550A9283 /* LegendEntry.swift */; };
@@ -286,6 +287,7 @@
 		BD02157CF8CEE1189BF681DA /* PieChartDataEntry.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; name = PieChartDataEntry.swift; path = Source/Charts/Data/Implementations/Standard/PieChartDataEntry.swift; sourceTree = "<group>"; };
 		BD5C6D20243EC2F19069AACD /* CandleStickChartRenderer.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; name = CandleStickChartRenderer.swift; path = Source/Charts/Renderers/CandleStickChartRenderer.swift; sourceTree = "<group>"; };
 		BFABD027DAF6851088F002AC /* LineChartDataProvider.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; name = LineChartDataProvider.swift; path = Source/Charts/Interfaces/LineChartDataProvider.swift; sourceTree = "<group>"; };
+		C03E6D8023DAAB2600083010 /* ChartDataTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ChartDataTests.swift; sourceTree = "<group>"; };
 		C31AA65EA27776F8C653C7E8 /* BarChartDataSet.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; name = BarChartDataSet.swift; path = Source/Charts/Data/Implementations/Standard/BarChartDataSet.swift; sourceTree = "<group>"; };
 		C52E8344160B5E689DA3C25C /* ChevronDownShapeRenderer.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; name = ChevronDownShapeRenderer.swift; path = Source/Charts/Renderers/Scatter/ChevronDownShapeRenderer.swift; sourceTree = "<group>"; };
 		C574E1BC7E12D937A5471EF8 /* Info.plist */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.plist.xml; name = Info.plist; path = "Tests/Supporting Files/Info.plist"; sourceTree = "<group>"; };
@@ -537,6 +539,7 @@
 				D2E1819D72CD7B6C4A4E8048 /* LineChartTests.swift */,
 				135F11CD20425AF600D655A3 /* PieChartTests.swift */,
 				064989451F5C99C7006E8BB3 /* Snapshot.swift */,
+				C03E6D8023DAAB2600083010 /* ChartDataTests.swift */,
 			);
 			name = Charts;
 			sourceTree = "<group>";
@@ -985,6 +988,7 @@
 				B66817462241E3CC00017CF1 /* HorizontalBarChartTests.swift in Sources */,
 				135F11CE20425AF600D655A3 /* PieChartTests.swift in Sources */,
 				064989461F5C99C7006E8BB3 /* Snapshot.swift in Sources */,
+				C03E6D8123DAAB2600083010 /* ChartDataTests.swift in Sources */,
 				224EFF991FBAAC4700CF9B3B /* EquatableTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

Source/Charts/Data/Implementations/Standard/ChartData.swift

@@ -349,10 +349,8 @@ open class ChartData: NSObject
         // TODO: Return nil instead of -1
         if ignorecase
         {
-            return dataSets.firstIndex {
-                guard let label = $0.label else { return false }
-                return label.caseInsensitiveCompare(label) == .orderedSame
-            } ?? -1
+            return dataSets.firstIndex { $0.label?.caseInsensitiveCompare(label) == .orderedSame }
+                ?? -1
         }
         else
         {