From 933c37dd2f6916ab302deab89b67cc07e07a75cc Mon Sep 17 00:00:00 2001
From: ChrisBenua <kpbenua@yandex.ru>
Date: Fri, 5 Sep 2025 21:26:16 +0300
Subject: [PATCH 1/3] reduce swift runtime overhead

---
 Sources/ReerJSON/JSONDecoderImpl.swift | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/Sources/ReerJSON/JSONDecoderImpl.swift b/Sources/ReerJSON/JSONDecoderImpl.swift
index 957c3e0..d979101 100644
--- a/Sources/ReerJSON/JSONDecoderImpl.swift
+++ b/Sources/ReerJSON/JSONDecoderImpl.swift
@@ -168,7 +168,7 @@ final class JSONDecoderImpl: Decoder {
         if type == Decimal.self {
             return try unboxDecimal(from: value, for: codingPathNode, additionalKey) as! T
         }
-        if let dictType = type as? StringDecodableDictionary.Type {
+        if !options.keyDecodingStrategy.isDefault, let dictType = type as? StringDecodableDictionary.Type {
             return try unboxDictionary(from: value, as: dictType, for: codingPathNode, additionalKey)
         }
         
@@ -1472,3 +1472,14 @@ private struct JSONUnkeyedDecodingContainer: UnkeyedDecodingContainer {
         return int
     }
 }
+
+private extension JSONDecoder.KeyDecodingStrategy {
+    var isDefault: Bool {
+        switch self {
+        case .useDefaultKeys:
+            return true
+        case .convertFromSnakeCase, .custom:
+            return false
+        }
+    }
+}

From 1ce7be959033b02b46dd78df547af97eb00d5009 Mon Sep 17 00:00:00 2001
From: ChrisBenua <kpbenua@yandex.ru>
Date: Fri, 5 Sep 2025 23:27:24 +0300
Subject: [PATCH 2/3] handle unknown default value

---
 Sources/ReerJSON/JSONDecoderImpl.swift | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Sources/ReerJSON/JSONDecoderImpl.swift b/Sources/ReerJSON/JSONDecoderImpl.swift
index d979101..a78ad47 100644
--- a/Sources/ReerJSON/JSONDecoderImpl.swift
+++ b/Sources/ReerJSON/JSONDecoderImpl.swift
@@ -1480,6 +1480,8 @@ private extension JSONDecoder.KeyDecodingStrategy {
             return true
         case .convertFromSnakeCase, .custom:
             return false
+        @unknown default:
+            return false
         }
     }
 }

From 7c65a6dedcf5966cc0d1e8a6010b895c2acfec34 Mon Sep 17 00:00:00 2001
From: ChrisBenua <kpbenua@edu.hse.ru>
Date: Mon, 8 Sep 2025 00:17:37 +0300
Subject: [PATCH 3/3] move to utilities

---
 Sources/ReerJSON/JSONDecoderImpl.swift | 13 -------------
 Sources/ReerJSON/Utilities.swift       | 12 ++++++++++++
 2 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/Sources/ReerJSON/JSONDecoderImpl.swift b/Sources/ReerJSON/JSONDecoderImpl.swift
index a78ad47..f90b99d 100644
--- a/Sources/ReerJSON/JSONDecoderImpl.swift
+++ b/Sources/ReerJSON/JSONDecoderImpl.swift
@@ -1472,16 +1472,3 @@ private struct JSONUnkeyedDecodingContainer: UnkeyedDecodingContainer {
         return int
     }
 }
-
-private extension JSONDecoder.KeyDecodingStrategy {
-    var isDefault: Bool {
-        switch self {
-        case .useDefaultKeys:
-            return true
-        case .convertFromSnakeCase, .custom:
-            return false
-        @unknown default:
-            return false
-        }
-    }
-}
diff --git a/Sources/ReerJSON/Utilities.swift b/Sources/ReerJSON/Utilities.swift
index 189a21a..7553bea 100644
--- a/Sources/ReerJSON/Utilities.swift
+++ b/Sources/ReerJSON/Utilities.swift
@@ -127,6 +127,18 @@ extension Dictionary : StringDecodableDictionary where Key == String, Value: Dec
     static var elementType: Decodable.Type { return Value.self }
 }
 
+extension JSONDecoder.KeyDecodingStrategy {
+    @inline(__always)
+    var isDefault: Bool {
+        switch self {
+        case .useDefaultKeys:
+            return true
+        default:
+            return false
+        }
+    }
+}
+
 // This is a workaround for the lack of a "set value only if absent" function for Dictionary.
 extension Optional {
     mutating func _setIfNil(to value: Wrapped) {