Throw error on bad expiring todo date format (#3626)

CHANGELOG.md

@@ -48,6 +48,10 @@
   [JP Simard](https://github.com/jpsim)
   [#3920](https://github.com/realm/SwiftLint/issues/3920)
 
+* Error by default on bad expiring todo date formatting.  
+  [Christopher Hale](https://github.com/chrispomeroyhale)
+  [#3636](https://github.com/realm/SwiftLint/pull/3626)
+
 ## 0.47.0: Smart Appliance
 
 #### Breaking

Source/SwiftLintFramework/Rules/Lint/ExpiringTodoRule.swift

@@ -5,6 +5,7 @@ public struct ExpiringTodoRule: ConfigurationProviderRule, OptInRule {
     enum ExpiryViolationLevel {
         case approachingExpiry
         case expired
+        case badFormatting
 
         var reason: String {
             switch self {
@@ -12,13 +13,15 @@ public struct ExpiringTodoRule: ConfigurationProviderRule, OptInRule {
                 return "TODO/FIXME is approaching its expiry and should be resolved soon."
             case .expired:
                 return "TODO/FIXME has expired and must be resolved."
+            case .badFormatting:
+                return "Expiring TODO/FIXME is incorrectly formatted."
             }
         }
     }
 
     public static let description = RuleDescription(
         identifier: "expiring_todo",
-        name: "ExpiringTodo",
+        name: "Expiring Todo",
         description: "TODOs and FIXMEs should be resolved prior to their expiry date.",
         kind: .lint,
         nonTriggeringExamples: [
@@ -36,7 +39,8 @@ public struct ExpiringTodoRule: ConfigurationProviderRule, OptInRule {
             Example("// TODO: [10/14/2019]\n"),
             Example("// FIXME: [10/14/2019]\n"),
             Example("// FIXME: [1/14/2019]\n"),
-            Example("// FIXME: [10/4/2019]\n")
+            Example("// FIXME: [10/14/2019]\n"),
+            Example("// TODO: [9999/14/10]\n")
         ]
     )
 
@@ -48,7 +52,7 @@ public struct ExpiringTodoRule: ConfigurationProviderRule, OptInRule {
         let regex = #"""
         \b(?:TODO|FIXME)(?::|\b)(?:(?!\b(?:TODO|FIXME)(?::|\b)).)*?\#
         \\#(configuration.dateDelimiters.opening)\#
-        (\d{1,4}\\#(configuration.dateSeparator)\d{1,2}\\#(configuration.dateSeparator)\d{1,4})\#
+        (\d{1,4}\\#(configuration.dateSeparator)\d{1,4}\\#(configuration.dateSeparator)\d{1,4})\#
         \\#(configuration.dateDelimiters.closing)
         """#
 
@@ -57,8 +61,7 @@ public struct ExpiringTodoRule: ConfigurationProviderRule, OptInRule {
                 syntaxKinds.allSatisfy({ $0.isCommentLike }),
                 checkingResult.numberOfRanges > 1,
                 case let range = checkingResult.range(at: 1),
-                let date = expiryDate(file: file, range: range),
-                let violationLevel = self.violationLevel(for: date),
+                let violationLevel = self.violationLevel(for: expiryDate(file: file, range: range)),
                 let severity = self.severity(for: violationLevel) else {
                 return nil
             }
@@ -90,10 +93,15 @@ public struct ExpiringTodoRule: ConfigurationProviderRule, OptInRule {
             return configuration.approachingExpirySeverity.severity
         case .expired:
             return configuration.expiredSeverity.severity
+        case .badFormatting:
+            return configuration.badFormattingSeverity.severity
         }
     }
 
-    private func violationLevel(for expiryDate: Date) -> ExpiryViolationLevel? {
+    private func violationLevel(for expiryDate: Date?) -> ExpiryViolationLevel? {
+        guard let expiryDate = expiryDate else {
+            return .badFormatting
+        }
         guard expiryDate.isAfterToday else {
             return .expired
         }

Source/SwiftLintFramework/Rules/RuleConfigurations/ExpiringTodoConfiguration.swift

@@ -12,14 +12,24 @@ public struct ExpiringTodoConfiguration: RuleConfiguration, Equatable {
     }
 
     public var consoleDescription: String {
-        return "(approaching_expiry_severity) \(approachingExpirySeverity.consoleDescription), " +
-        "(reached_or_passed_expiry_severity) \(expiredSeverity.consoleDescription)"
+        let descriptions = [
+            "approaching_expiry_severity: \(approachingExpirySeverity.consoleDescription)",
+            "expired_severity: \(expiredSeverity.consoleDescription)",
+            "bad_formatting_severity: \(badFormattingSeverity.consoleDescription)",
+            "approaching_expiry_threshold: \(approachingExpiryThreshold)",
+            "date_format: \(dateFormat)",
+            "date_delimiters: { opening: \(dateDelimiters.opening)", "closing: \(dateDelimiters.closing) }",
+            "date_separator: \(dateSeparator)"
+        ]
+        return descriptions.joined(separator: ", ")
     }
 
     private(set) var approachingExpirySeverity: SeverityConfiguration
 
     private(set) var expiredSeverity: SeverityConfiguration
 
+    private(set) var badFormattingSeverity: SeverityConfiguration
+
     // swiftlint:disable:next todo
     /// The number of days prior to expiry before the TODO emits a violation
     private(set) var approachingExpiryThreshold: Int
@@ -33,12 +43,14 @@ public struct ExpiringTodoConfiguration: RuleConfiguration, Equatable {
     public init(
         approachingExpirySeverity: SeverityConfiguration = .init(.warning),
         expiredSeverity: SeverityConfiguration = .init(.error),
+        badFormattingSeverity: SeverityConfiguration = .init(.error),
         approachingExpiryThreshold: Int = 15,
         dateFormat: String = "MM/dd/yyyy",
         dateDelimiters: DelimiterConfiguration = .default,
         dateSeparator: String = "/") {
         self.approachingExpirySeverity = approachingExpirySeverity
         self.expiredSeverity = expiredSeverity
+        self.badFormattingSeverity = badFormattingSeverity
         self.approachingExpiryThreshold = approachingExpiryThreshold
         self.dateDelimiters = dateDelimiters
         self.dateFormat = dateFormat
@@ -56,6 +68,9 @@ public struct ExpiringTodoConfiguration: RuleConfiguration, Equatable {
         if let expiredConfiguration = configurationDict["expired_severity"] {
             try expiredSeverity.apply(configuration: expiredConfiguration)
         }
+        if let badFormattingConfiguration = configurationDict["bad_formatting_severity"] {
+            try badFormattingSeverity.apply(configuration: badFormattingConfiguration)
+        }
         if let approachingExpiryThreshold = configurationDict["approaching_expiry_threshold"] as? Int {
             self.approachingExpiryThreshold = approachingExpiryThreshold
         }

Tests/SwiftLintFrameworkTests/ExpiringTodoRuleTests.swift

@@ -134,6 +134,18 @@ class ExpiringTodoRuleTests: XCTestCase {
         XCTAssertEqual(violations[0].location.line, 2)
     }
 
+    func testBadExpiryTodoFormat() throws {
+        let ruleConfig: ExpiringTodoConfiguration = .init(
+            dateFormat: "dd/yyyy/MM"
+        )
+        config = makeConfiguration(with: ruleConfig)
+
+        let example = Example("fatalError() // TODO: [31/01/2020] Implement")
+        let violations = self.violations(example)
+        XCTAssertEqual(violations.count, 1)
+        XCTAssertEqual(violations.first?.reason, "Expiring TODO/FIXME is incorrectly formatted.")
+    }
+
     private func violations(_ example: Example) -> [StyleViolation] {
         return SwiftLintFrameworkTests.violations(example, config: config)
     }
@@ -155,7 +167,7 @@ class ExpiringTodoRuleTests: XCTestCase {
             daysToAdvance = ruleConfiguration.approachingExpiryThreshold
         case .expired?:
             daysToAdvance = 0
-        case nil:
+        case .badFormatting?, nil:
             daysToAdvance = ruleConfiguration.approachingExpiryThreshold + 1
         }
 
@@ -174,6 +186,7 @@ class ExpiringTodoRuleTests: XCTestCase {
             serializedConfig = [
                 "expired_severity": config.expiredSeverity.severity.rawValue,
                 "approaching_expiry_severity": config.approachingExpirySeverity.severity.rawValue,
+                "bad_formatting_severity": config.badFormattingSeverity.severity.rawValue,
                 "approaching_expiry_threshold": config.approachingExpiryThreshold,
                 "date_format": config.dateFormat,
                 "date_delimiters": [