From 413d2ba88a3b07b528c261afa383e198c2508b83 Mon Sep 17 00:00:00 2001
From: Marat Al <m.alekperov@gmail.com>
Date: Sun, 6 Mar 2022 23:43:50 +0100
Subject: [PATCH 1/2] Added `cause` property to `ARTErrorInfo` as a reflection
 of `NSUnderlyingErrorKey` value from `NSError.userInfo`.

---
 Source/ARTStatus.h | 1 +
 Source/ARTStatus.m | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/Source/ARTStatus.h b/Source/ARTStatus.h
index 812c11863..9feb71552 100644
--- a/Source/ARTStatus.h
+++ b/Source/ARTStatus.h
@@ -191,6 +191,7 @@ FOUNDATION_EXPORT NSString *const ARTAblyMessageNoMeansToRenewToken;
 @interface ARTErrorInfo : NSError
 
 @property (readonly) NSString *message;
+@property (nullable, readonly) NSError *cause;
 @property (nullable, readonly) NSString *reason;
 @property (readonly) NSInteger statusCode;
 @property (nullable, readonly) NSString *href;
diff --git a/Source/ARTStatus.m b/Source/ARTStatus.m
index f06f35e2d..cef2eef6c 100644
--- a/Source/ARTStatus.m
+++ b/Source/ARTStatus.m
@@ -96,6 +96,10 @@ - (NSString *)reason {
     return reason;
 }
 
+- (NSError *)cause {
+    return self.userInfo[NSUnderlyingErrorKey];
+}
+
 - (NSInteger)statusCode {
     return [self artStatusCode];
 }

From 6fb1f954a09362e469ccdcd596e3a99f67daadaa Mon Sep 17 00:00:00 2001
From: Marat Al <m.alekperov@gmail.com>
Date: Mon, 7 Mar 2022 00:05:54 +0100
Subject: [PATCH 2/2] Converted `cause` to `ARTErrorInfo`

---
 Source/ARTStatus.h | 2 +-
 Source/ARTStatus.m | 8 ++++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/Source/ARTStatus.h b/Source/ARTStatus.h
index 9feb71552..38e7559e2 100644
--- a/Source/ARTStatus.h
+++ b/Source/ARTStatus.h
@@ -191,11 +191,11 @@ FOUNDATION_EXPORT NSString *const ARTAblyMessageNoMeansToRenewToken;
 @interface ARTErrorInfo : NSError
 
 @property (readonly) NSString *message;
-@property (nullable, readonly) NSError *cause;
 @property (nullable, readonly) NSString *reason;
 @property (readonly) NSInteger statusCode;
 @property (nullable, readonly) NSString *href;
 @property (nullable, readonly) NSString *requestId;
+@property (nullable, readonly) ARTErrorInfo *cause;
 
 + (ARTErrorInfo *)createWithCode:(NSInteger)code message:(NSString *)message;
 + (ARTErrorInfo *)createWithCode:(NSInteger)code status:(NSInteger)status message:(NSString *)message;
diff --git a/Source/ARTStatus.m b/Source/ARTStatus.m
index cef2eef6c..f32ae7b39 100644
--- a/Source/ARTStatus.m
+++ b/Source/ARTStatus.m
@@ -96,8 +96,12 @@ - (NSString *)reason {
     return reason;
 }
 
-- (NSError *)cause {
-    return self.userInfo[NSUnderlyingErrorKey];
+- (ARTErrorInfo *)cause {
+    NSError *underlyingError = self.userInfo[NSUnderlyingErrorKey];
+    if (underlyingError == nil) {
+        return nil;
+    }
+    return [ARTErrorInfo createFromNSError:underlyingError];
 }
 
 - (NSInteger)statusCode {