From 49e39f697465d42a85c5557d8ca3f3ae0649d6a8 Mon Sep 17 00:00:00 2001
From: Rob Napier <rob@neverwood.org>
Date: Sun, 17 Jul 2022 11:28:27 -0400
Subject: [PATCH] Add failedDecodes to LossyArray

---
 Sources/BetterCodable/LossyArray.swift        | 23 +++++++++++++++++--
 .../BetterCodableTests/LossyArrayTests.swift  |  4 ++++
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/Sources/BetterCodable/LossyArray.swift b/Sources/BetterCodable/LossyArray.swift
index 6813124..75fe071 100644
--- a/Sources/BetterCodable/LossyArray.swift
+++ b/Sources/BetterCodable/LossyArray.swift
@@ -6,10 +6,18 @@
 @propertyWrapper
 public struct LossyArray<T> {
     public var wrappedValue: [T]
+    public var projectedValue: Self { self }
 
     public init(wrappedValue: [T]) {
         self.wrappedValue = wrappedValue
     }
+
+    public struct FailedDecode {
+        var codingPath: [CodingKey]
+        var error: Error
+    }
+
+    public var failedDecodes: [FailedDecode] = []
 }
 
 extension LossyArray: Decodable where T: Decodable {
@@ -19,16 +27,19 @@ extension LossyArray: Decodable where T: Decodable {
         var container = try decoder.unkeyedContainer()
 
         var elements: [T] = []
+        var failedDecodes: [FailedDecode] = []
         while !container.isAtEnd {
             do {
                 let value = try container.decode(T.self)
                 elements.append(value)
             } catch {
+                failedDecodes.append(FailedDecode(codingPath: container.codingPath, error: error))
                 _ = try? container.decode(AnyDecodableValue.self)
             }
         }
 
         self.wrappedValue = elements
+        self.failedDecodes = failedDecodes
     }
 }
 
@@ -38,5 +49,13 @@ extension LossyArray: Encodable where T: Encodable {
     }
 }
 
-extension LossyArray: Equatable where T: Equatable { }
-extension LossyArray: Hashable where T: Hashable { }
+extension LossyArray: Equatable where T: Equatable {
+    public static func == (lhs: LossyArray<T>, rhs: LossyArray<T>) -> Bool {
+        lhs.wrappedValue == rhs.wrappedValue
+    }
+}
+extension LossyArray: Hashable where T: Hashable {
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(wrappedValue)
+    }
+}
diff --git a/Tests/BetterCodableTests/LossyArrayTests.swift b/Tests/BetterCodableTests/LossyArrayTests.swift
index f075388..e9427fd 100644
--- a/Tests/BetterCodableTests/LossyArrayTests.swift
+++ b/Tests/BetterCodableTests/LossyArrayTests.swift
@@ -17,6 +17,8 @@ class LossyArrayTests: XCTestCase {
         let fixture = try JSONDecoder().decode(Fixture.self, from: jsonData)
         XCTAssertEqual(fixture.values, [1, 3, 4])
         XCTAssertEqual(fixture.nonPrimitiveValues, [])
+        XCTAssertEqual(fixture.$values.failedDecodes.count, 1)
+        XCTAssertEqual(fixture.$nonPrimitiveValues.failedDecodes.count, 1)
     }
 
 	func testDecodingLossyArrayIgnoresLossyElements() throws {
@@ -24,6 +26,8 @@ class LossyArrayTests: XCTestCase {
         let fixture = try JSONDecoder().decode(Fixture.self, from: jsonData)
         XCTAssertEqual(fixture.values, [1, 4])
         XCTAssertEqual(fixture.nonPrimitiveValues, [])
+        XCTAssertEqual(fixture.$values.failedDecodes.count, 3)
+        XCTAssertEqual(fixture.$nonPrimitiveValues.failedDecodes.count, 1)
 	}
     
     func testEncodingDecodedLossyArrayIgnoresFailableElements() throws {