From 4f937979a5c56eeb64e840125fade12af2b7488f Mon Sep 17 00:00:00 2001
From: Simon Whitty <simon@whileloop.com>
Date: Wed, 26 Jun 2024 16:50:00 +1000
Subject: [PATCH] Decode doubles as Int if exactly represented

---
 Sources/KeyValueDecoder.swift    | 10 +++++++++-
 Tests/KeyValueDecoderTests.swift | 24 ++++++++++++++++++++----
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/Sources/KeyValueDecoder.swift b/Sources/KeyValueDecoder.swift
index 6c08430..65825d7 100644
--- a/Sources/KeyValueDecoder.swift
+++ b/Sources/KeyValueDecoder.swift
@@ -155,7 +155,15 @@ private extension KeyValueDecoder {
                     throw DecodingError.typeMismatch(type, context)
                 }
                 return val
-            } else {
+            } else if let double = (value as? NSNumber)?.getDoubleValue() {
+                let val = T(double)
+                guard Double(val) == double else {
+                    let context = DecodingError.Context(codingPath: codingPath, debugDescription: "\(valueDescription) at \(codingPath.makeKeyPath()), cannot be exactly represented by \(type)")
+                    throw DecodingError.typeMismatch(type, context)
+                }
+                return val
+            }
+            else {
                 let context = DecodingError.Context(codingPath: codingPath, debugDescription: "Expected BinaryInteger at \(codingPath.makeKeyPath()), found \(valueDescription)")
                 if decodeNil() {
                     throw DecodingError.valueNotFound(type, context)
diff --git a/Tests/KeyValueDecoderTests.swift b/Tests/KeyValueDecoderTests.swift
index e381e1b..929a829 100644
--- a/Tests/KeyValueDecoderTests.swift
+++ b/Tests/KeyValueDecoderTests.swift
@@ -103,6 +103,14 @@ final class KeyValueDecoderTests: XCTestCase {
             try KeyValueDecoder.decode(Int16.self, from: NSNumber(10)),
             10
         )
+        XCTAssertEqual(
+            try KeyValueDecoder.decode(Int16.self, from: 10.0),
+            10
+        )
+        XCTAssertEqual(
+            try KeyValueDecoder.decode(Int16.self, from: NSNumber(10.0)),
+            10
+        )
         XCTAssertThrowsError(
             try KeyValueDecoder.decode(Int8.self, from: Int16.max)
         )
@@ -129,6 +137,14 @@ final class KeyValueDecoderTests: XCTestCase {
             try KeyValueDecoder.decode(UInt8.self, from: NSNumber(10)),
             10
         )
+        XCTAssertEqual(
+            try KeyValueDecoder.decode(UInt8.self, from: 10.0),
+            10
+        )
+        XCTAssertEqual(
+            try KeyValueDecoder.decode(UInt8.self, from: NSNumber(10.0)),
+            10
+        )
         XCTAssertThrowsError(
             try KeyValueDecoder.decode(UInt8.self, from: UInt16.max)
         )
@@ -480,8 +496,8 @@ final class KeyValueDecoderTests: XCTestCase {
 
     func testDecodes_UnkeyedInts() {
         XCTAssertEqual(
-            try KeyValueDecoder.decode([Int].self, from: [-10, 20, 30]),
-            [-10, 20, 30]
+            try KeyValueDecoder.decode([Int].self, from: [-10, 20, 30, 40.0, -50.0]),
+            [-10, 20, 30, 40, -50]
         )
         XCTAssertEqual(
             try KeyValueDecoder.decode([Int8].self, from: [10, -20, 30]),
@@ -610,8 +626,8 @@ final class KeyValueDecoderTests: XCTestCase {
 
     func testDecodes_UnkeyedUInts() {
         XCTAssertEqual(
-            try KeyValueDecoder.decode([UInt].self, from: [10, 20, 30]),
-            [10, 20, 30]
+            try KeyValueDecoder.decode([UInt].self, from: [10, 20, 30, 40.0]),
+            [10, 20, 30, 40]
         )
         XCTAssertEqual(
             try KeyValueDecoder.decode([UInt8].self, from: [10, 20, 30]),