Add validation to DateTime and Date.Components initializers

Makes DateTime.init(year:month:day:...) and Date.Components.init
throwing to validate component ranges per RFC 5322 requirements:
- month: 1-12
- day: 1-31 (validated for specific month/year, including leap years)
- hour: 0-23
- minute: 0-59
- second: 0-60 (allowing leap second)
- weekday: 0-6

New error cases in RFC_5322.Date.Error:
- monthOutOfRange(Int)
- dayOutOfRange(Int, month: Int, year: Int)
- hourOutOfRange(Int)
- minuteOutOfRange(Int)
- secondOutOfRange(Int)
- weekdayOutOfRange(Int)

Updates:
- All test functions calling component-based init now marked `throws`
- Added 6 comprehensive validation tests
- Parse function properly propagates validation errors
- Internal components computed property uses try! (safe invariant)

All 158 tests pass.

Author: coenttb

Package.swift

@@ -1,44 +1,70 @@
 // swift-tools-version:6.0
 
-import Foundation
 import PackageDescription
 
 extension String {
     static let rfc5322: Self = "RFC_5322"
+    static let rfc5322Foundation: Self = "RFC_5322_Foundation"
 }
 
+extension String { var tests: Self { self + " Tests" } }
+
 extension Target.Dependency {
     static var rfc5322: Self { .target(name: .rfc5322) }
+    static var rfc5322Foundation: Self { .target(name: .rfc5322Foundation) }
     static var rfc1123: Self { .product(name: "RFC_1123", package: "swift-rfc-1123") }
+    static var standards: Self { .product(name: "Standards", package: "swift-standards") }
+    static var incits_4_1986: Self { .product(name: "INCITS_4_1986", package: "swift-incits-4-1986") }
+    static var standardsTestSupport: Self { .product(name: "StandardsTestSupport", package: "swift-standards") }
 }
 
 let package = Package(
     name: "swift-rfc-5322",
     platforms: [
-        .macOS(.v13),
-        .iOS(.v16)
+        .macOS(.v15),
+        .iOS(.v18),
+        .tvOS(.v18),
+        .watchOS(.v11)
     ],
     products: [
         .library(name: .rfc5322, targets: [.rfc5322]),
+        .library(name: .rfc5322Foundation, targets: [.rfc5322Foundation]),
     ],
     dependencies: [
         .package(url: "https://github.com/swift-standards/swift-rfc-1123.git", from: "0.0.1"),
+        .package(url: "https://github.com/swift-standards/swift-standards.git", from: "0.1.0"),
+        .package(url: "https://github.com/swift-standards/swift-incits-4-1986.git", from: "0.1.0")
     ],
     targets: [
         .target(
             name: .rfc5322,
             dependencies: [
-                .rfc1123
+                .rfc1123,
+                .standards,
+                .incits_4_1986
+            ]
+        ),
+        .target(
+            name: .rfc5322Foundation,
+            dependencies: [
+                .rfc5322
             ]
         ),
         .testTarget(
             name: .rfc5322.tests,
             dependencies: [
-                .rfc5322
+                .rfc5322,
+                .incits_4_1986,
+                .standardsTestSupport
+            ]
+        ),
+        .testTarget(
+            name: .rfc5322Foundation.tests,
+            dependencies: [
+                .rfc5322,
+                .rfc5322Foundation
             ]
         ),
     ],
     swiftLanguageModes: [.v6]
 )
-
-extension String { var tests: Self { self + " Tests" } }

README.md

@@ -88,8 +88,8 @@ let message = RFC_5322.Message(
     body: "Hello, World!".data(using: .utf8)!
 )
 
-// Render to RFC 5322 format
-let emlContent = message.render()
+// Convert to RFC 5322 format
+let emlContent = String(message)
 print(emlContent)
 // From: John Doe <[email protected]>
 // To: [email protected]
@@ -177,9 +177,16 @@ public struct Message: Hashable, Sendable {
     public let additionalHeaders: [Header]
     public let mimeVersion: String
 
-    public func render() -> String
     public var bodyString: String?
-    public static func generateMessageId(from: EmailAddress) -> String
+    public static func generateMessageId(from: EmailAddress, uniqueId: String) -> String
+}
+
+extension [UInt8] {
+    public init(_ message: RFC_5322.Message)
+}
+
+extension String {
+    public init(_ message: RFC_5322.Message)
 }
 ```
 

Sources/RFC_5322/RFC 5322 Date.swift

@@ -17,6 +17,8 @@ extension RFC_5322.Date {
         public let second: Int     // 0-60 (allowing leap second)
         public let weekday: Int    // 0=Sunday, 6=Saturday
 
+        /// Creates date components with validation
+        /// - Throws: `RFC_5322.Date.Error` if any component is out of valid range
         public init(
             year: Int,
             month: Int,
@@ -25,7 +27,38 @@ extension RFC_5322.Date {
             minute: Int,
             second: Int,
             weekday: Int
-        ) {
+        ) throws {
+            // Validate month
+            guard (1...12).contains(month) else {
+                throw RFC_5322.Date.Error.monthOutOfRange(month)
+            }
+
+            // Validate day for the given month and year
+            let maxDay = Self.daysInMonth(month, year: year)
+            guard (1...maxDay).contains(day) else {
+                throw RFC_5322.Date.Error.dayOutOfRange(day, month: month, year: year)
+            }
+
+            // Validate hour
+            guard (0...23).contains(hour) else {
+                throw RFC_5322.Date.Error.hourOutOfRange(hour)
+            }
+
+            // Validate minute
+            guard (0...59).contains(minute) else {
+                throw RFC_5322.Date.Error.minuteOutOfRange(minute)
+            }
+
+            // Validate second (allowing 60 for leap second)
+            guard (0...60).contains(second) else {
+                throw RFC_5322.Date.Error.secondOutOfRange(second)
+            }
+
+            // Validate weekday
+            guard (0...6).contains(weekday) else {
+                throw RFC_5322.Date.Error.weekdayOutOfRange(weekday)
+            }
+
             self.year = year
             self.month = month
             self.day = day
@@ -34,5 +67,24 @@ extension RFC_5322.Date {
             self.second = second
             self.weekday = weekday
         }
+
+        /// Returns the number of days in the given month for the given year
+        private static func daysInMonth(_ month: Int, year: Int) -> Int {
+            switch month {
+            case 1, 3, 5, 7, 8, 10, 12:
+                return 31
+            case 4, 6, 9, 11:
+                return 30
+            case 2:
+                return isLeapYear(year) ? 29 : 28
+            default:
+                return 0
+            }
+        }
+
+        /// Returns true if the year is a leap year
+        private static func isLeapYear(_ year: Int) -> Bool {
+            (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)
+        }
     }
 }

Sources/RFC_5322/RFC_5322.Date.Components.swift

@@ -6,8 +6,7 @@
 //
 
 extension RFC_5322.Date {
-
-    /// Errors that can occur when parsing RFC 5322 date-time strings
+    /// Errors that can occur when parsing RFC 5322 date-time strings or creating date components
     public enum Error: Swift.Error, Sendable, Equatable {
         case invalidFormat(String)
         case invalidDayName(String)
@@ -20,5 +19,13 @@ extension RFC_5322.Date {
         case invalidSecond(String)
         case invalidTimezone(String)
         case weekdayMismatch(expected: String, actual: String)
+
+        // Component validation errors
+        case monthOutOfRange(Int)           // Must be 1-12
+        case dayOutOfRange(Int, month: Int, year: Int)  // Must be valid for month/year
+        case hourOutOfRange(Int)            // Must be 0-23
+        case minuteOutOfRange(Int)          // Must be 0-59
+        case secondOutOfRange(Int)          // Must be 0-60 (allowing leap second)
+        case weekdayOutOfRange(Int)         // Must be 0-6
     }
 }