fix: validate each not taking required parameter into account

Sources/Vapor/Validation/Validation.swift

@@ -52,18 +52,26 @@ public struct Validation {
         self.init { container in
             let result: ValidatorResult
             do {
-                var results: [[ValidatorResult]] = []
-                var array = try container.nestedUnkeyedContainer(forKey: key)
-                var i = 0
-                while !array.isAtEnd {
-                    defer { i += 1 }
-                    var validations = Validations()
-                    factory(i, &validations)
-                    let nested = try array.nestedContainer(keyedBy: ValidationKey.self)
-                    let result = validations.validate(nested)
-                    results.append(result.results)
+                if container.contains(key), !required, try container.decodeNil(forKey: key) {
+                    result = ValidatorResults.Skipped()
+                } else if container.contains(key) {
+                    var results: [[ValidatorResult]] = []
+                    var array = try container.nestedUnkeyedContainer(forKey: key)
+                    var i = 0
+                    while !array.isAtEnd {
+                        defer { i += 1 }
+                        var validations = Validations()
+                        factory(i, &validations)
+                        let nested = try array.nestedContainer(keyedBy: ValidationKey.self)
+                        let result = validations.validate(nested)
+                        results.append(result.results)
+                    }
+                    result = ValidatorResults.NestedEach(results: results)
+                } else if required {
+                    result = ValidatorResults.Missing()
+                } else {
+                    result = ValidatorResults.Skipped()
                 }
-                result = ValidatorResults.NestedEach(results: results)
             } catch {
                 result = ValidatorResults.Codable(error: error)
             }

Tests/VaporTests/ValidationTests.swift

@@ -233,13 +233,21 @@ class ValidationTests: XCTestCase {
             var name: String
             var age: Int
             var hobbies: [Hobby]
+            var allergies: [Allergy]?
 
             struct Hobby: Codable {
                 var title: String
                 init(title: String) {
                     self.title = title
                 }
             }
+
+            struct Allergy: Codable {
+                var title: String
+                init(title: String) {
+                    self.title = title
+                }
+            }
 
             static func validations(_ v: inout Validations) {
                 v.add("name", as: String.self, is: .count(5...) && .alphanumeric)
@@ -248,6 +256,9 @@ class ValidationTests: XCTestCase {
                     hobby.add("title", as: String.self, is: .count(5...) && .characterSet(.alphanumerics + .whitespaces))
                 }
                 v.add("hobbies", as: [Hobby].self, is: !.empty)
+                v.add(each: "allergies", required: false) { i, allergy in
+                    allergy.add("title", as: String.self, is: .characterSet(.letters))
+                }
             }
         }
 
@@ -268,6 +279,54 @@ class ValidationTests: XCTestCase {
         XCTAssertThrowsError(try User.validate(json: invalidNestedArray)) { error in
             XCTAssertEqual("\(error)", "hobbies at index 0 title contains '€' (allowed: whitespace, A-Z, a-z, 0-9) and at index 1 title is less than minimum of 5 character(s)")
         }
+
+        let invalidNestedArray2 = """
+        {
+            "name": "Tanner",
+            "age": 24,
+            "allergies": [
+                {
+                    "title": "Peanuts"
+                }
+            ]
+        }
+        """
+        XCTAssertThrowsError(try User.validate(json: invalidNestedArray2)) { error in
+            XCTAssertEqual("\(error)", "hobbies is required, hobbies is required")
+        }
+
+        let invalidNestedArray3 = """
+        {
+            "name": "Tanner",
+            "age": 24,
+            "hobbies": [
+                {
+                    "title": "Football"
+                }
+            ],
+            "allergies": [
+                {
+                    "title": "Peanuts€"
+                }
+            ]
+        }
+        """
+        XCTAssertThrowsError(try User.validate(json: invalidNestedArray3)) { error in
+            XCTAssertEqual("\(error)", "allergies at index 0 title contains '€' (allowed: A-Z, a-z)")
+        }
+
+        let validNestedArray = """
+        {
+            "name": "Tanner",
+            "age": 24,
+            "hobbies": [
+                {
+                    "title": "Football"
+                }
+            ],
+        }
+        """
+        XCTAssertNoThrow(try User.validate(json: validNestedArray))
     }
 
     func testValidateNestedEachIndex() throws {