Added lenient command line option

README.md

@@ -718,6 +718,9 @@ allow_zero_lintable_files: false
 # If true, SwiftLint will treat all warnings as errors.
 strict: false
 
+# If true, SwiftLint will treat all errors as warnings.
+lenient: false
+
 # The path to a baseline file, which will be used to filter out detected violations.
 baseline: Baseline.json
 

Source/SwiftLintCore/Extensions/Configuration+Merging.swift

@@ -26,6 +26,7 @@ extension Configuration {
             cachePath: cachePath,
             allowZeroLintableFiles: childConfiguration.allowZeroLintableFiles,
             strict: childConfiguration.strict,
+            lenient: childConfiguration.lenient,
             baseline: childConfiguration.baseline,
             writeBaseline: childConfiguration.writeBaseline,
             checkForUpdates: childConfiguration.checkForUpdates

Source/SwiftLintCore/Extensions/Configuration+Parsing.swift

@@ -15,6 +15,7 @@ extension Configuration {
         case analyzerRules = "analyzer_rules"
         case allowZeroLintableFiles = "allow_zero_lintable_files"
         case strict = "strict"
+        case lenient = "lenient"
         case baseline = "baseline"
         case writeBaseline = "write_baseline"
         case checkForUpdates = "check_for_updates"
@@ -103,6 +104,7 @@ extension Configuration {
             pinnedVersion: dict[Key.swiftlintVersion.rawValue].map { ($0 as? String) ?? String(describing: $0) },
             allowZeroLintableFiles: dict[Key.allowZeroLintableFiles.rawValue] as? Bool ?? false,
             strict: dict[Key.strict.rawValue] as? Bool ?? false,
+            lenient: dict[Key.lenient.rawValue] as? Bool ?? false,
             baseline: dict[Key.baseline.rawValue] as? String,
             writeBaseline: dict[Key.writeBaseline.rawValue] as? String,
             checkForUpdates: dict[Key.checkForUpdates.rawValue] as? Bool ?? false

Source/SwiftLintCore/Models/Configuration.swift

@@ -38,6 +38,9 @@ public struct Configuration {
     /// Treat warnings as errors.
     public let strict: Bool
 
+    /// Treat errors as warnings.
+    public let lenient: Bool
+
     /// The path to read a baseline from.
     public let baseline: String?
 
@@ -83,6 +86,7 @@ public struct Configuration {
         cachePath: String?,
         allowZeroLintableFiles: Bool,
         strict: Bool,
+        lenient: Bool,
         baseline: String?,
         writeBaseline: String?,
         checkForUpdates: Bool
@@ -97,6 +101,7 @@ public struct Configuration {
         self.cachePath = cachePath
         self.allowZeroLintableFiles = allowZeroLintableFiles
         self.strict = strict
+        self.lenient = lenient
         self.baseline = baseline
         self.writeBaseline = writeBaseline
         self.checkForUpdates = checkForUpdates
@@ -117,6 +122,7 @@ public struct Configuration {
         cachePath = configuration.cachePath
         allowZeroLintableFiles = configuration.allowZeroLintableFiles
         strict = configuration.strict
+        lenient = configuration.lenient
         baseline = configuration.baseline
         writeBaseline = configuration.writeBaseline
         checkForUpdates = configuration.checkForUpdates
@@ -143,6 +149,7 @@ public struct Configuration {
     /// - parameter allowZeroLintableFiles: Allow SwiftLint to exit successfully when passed ignored or unlintable
     ///                                     files.
     /// - parameter strict:                 Treat warnings as errors.
+    /// - parameter lenient:                Treat errors as warnings.
     /// - parameter baseline:               The path to read a baseline from.
     /// - parameter writeBaseline:          The path to write a baseline to.
     /// - parameter checkForUpdates:        Check for updates to SwiftLint.
@@ -160,6 +167,7 @@ public struct Configuration {
         pinnedVersion: String? = nil,
         allowZeroLintableFiles: Bool = false,
         strict: Bool = false,
+        lenient: Bool = false,
         baseline: String? = nil,
         writeBaseline: String? = nil,
         checkForUpdates: Bool = false
@@ -189,6 +197,7 @@ public struct Configuration {
             cachePath: cachePath,
             allowZeroLintableFiles: allowZeroLintableFiles,
             strict: strict,
+            lenient: lenient,
             baseline: baseline,
             writeBaseline: writeBaseline,
             checkForUpdates: checkForUpdates
@@ -298,6 +307,7 @@ extension Configuration: Hashable {
         hasher.combine(reporter)
         hasher.combine(allowZeroLintableFiles)
         hasher.combine(strict)
+        hasher.combine(lenient)
         hasher.combine(baseline)
         hasher.combine(writeBaseline)
         hasher.combine(checkForUpdates)
@@ -319,6 +329,7 @@ extension Configuration: Hashable {
             lhs.fileGraph == rhs.fileGraph &&
             lhs.allowZeroLintableFiles == rhs.allowZeroLintableFiles &&
             lhs.strict == rhs.strict &&
+            lhs.lenient == rhs.lenient &&
             lhs.baseline == rhs.baseline &&
             lhs.writeBaseline == rhs.writeBaseline &&
             lhs.checkForUpdates == rhs.checkForUpdates &&

Source/swiftlint/Helpers/LintOrAnalyzeCommand.swift

@@ -71,6 +71,7 @@ struct LintOrAnalyzeCommand {
                 currentViolations = applyLeniency(
                     options: options,
                     strict: builder.configuration.strict,
+                    lenient: builder.configuration.lenient,
                     violations: violationsBeforeLeniency
                 )
                 visitorMutationQueue.sync {
@@ -81,6 +82,7 @@ struct LintOrAnalyzeCommand {
                 currentViolations = applyLeniency(
                     options: options,
                     strict: builder.configuration.strict,
+                    lenient: builder.configuration.lenient,
                     violations: linter.styleViolations(using: builder.storage)
                 )
             }
@@ -175,11 +177,14 @@ struct LintOrAnalyzeCommand {
     private static func applyLeniency(
         options: LintOrAnalyzeOptions,
         strict: Bool,
+        lenient: Bool,
         violations: [StyleViolation]
     ) -> [StyleViolation] {
+        // config file settings can be overridden by either `--strict` or `--lenient` command line options
         let strict = (strict && !options.lenient) || options.strict
+        let lenient = (lenient && !options.strict) || options.lenient
 
-        switch (options.lenient, strict) {
+        switch (lenient, strict) {
         case (false, false):
             return violations
 
@@ -200,7 +205,7 @@ struct LintOrAnalyzeCommand {
             }
 
         case (true, true):
-            queuedFatalError("Invalid command line options: 'lenient' and 'strict' are mutually exclusive.")
+            queuedFatalError("Invalid command line or config options: 'lenient' and 'strict' are mutually exclusive.")
         }
     }
 

Tests/SwiftLintFrameworkTests/ConfigurationTests.swift

@@ -56,6 +56,7 @@ final class ConfigurationTests: SwiftLintTestCase {
         XCTAssertEqual(reporterFrom(identifier: config.reporter).identifier, "xcode")
         XCTAssertFalse(config.allowZeroLintableFiles)
         XCTAssertFalse(config.strict)
+        XCTAssertFalse(config.lenient)
         XCTAssertNil(config.baseline)
         XCTAssertNil(config.writeBaseline)
         XCTAssertFalse(config.checkForUpdates)
@@ -447,6 +448,11 @@ final class ConfigurationTests: SwiftLintTestCase {
         XCTAssertTrue(configuration.strict)
     }
 
+    func testLenient() throws {
+        let configuration = try Configuration(dict: ["lenient": true])
+        XCTAssertTrue(configuration.lenient)
+    }
+
     func testBaseline() throws {
         let baselinePath = "Baseline.json"
         let configuration = try Configuration(dict: ["baseline": baselinePath])