From 07d196c54fd25f3457d0c77eb7eefe41db8281ef Mon Sep 17 00:00:00 2001
From: Boris Zbarsky <bzbarsky@apple.com>
Date: Sat, 18 Feb 2023 01:01:22 -0500
Subject: [PATCH] Stop sticking an MTRErrorHolder in the userInfo of NSErrors.

Otherwise the errors we create cannot be usefully encoded/decoded.

Fixes https://github.com/project-chip/connectedhomeip/issues/22388
---
 .../commands/common/MTRError.mm                 |  7 +++++--
 src/darwin/Framework/CHIP/MTRError.mm           | 17 +++++++++++------
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/examples/darwin-framework-tool/commands/common/MTRError.mm b/examples/darwin-framework-tool/commands/common/MTRError.mm
index c393682a7a84e0..5d348c83c7fdf3 100644
--- a/examples/darwin-framework-tool/commands/common/MTRError.mm
+++ b/examples/darwin-framework-tool/commands/common/MTRError.mm
@@ -25,6 +25,8 @@
 #import <inet/InetError.h>
 #import <lib/support/TypeTraits.h>
 
+#import <objc/runtime.h>
+
 CHIP_ERROR MTRErrorToCHIPErrorCode(NSError * error)
 {
     if (error == nil) {
@@ -43,8 +45,9 @@ CHIP_ERROR MTRErrorToCHIPErrorCode(NSError * error)
         return CHIP_ERROR_INTERNAL;
     }
 
-    if (error.userInfo != nil) {
-        id underlyingError = error.userInfo[@"underlyingError"];
+    {
+        void * key = (__bridge void *) NSClassFromString(@"MTRErrorHolder");
+        id underlyingError = objc_getAssociatedObject(error, key);
         if (underlyingError != nil) {
             NSValue * chipErrorValue = [underlyingError valueForKey:@"error"];
             if (chipErrorValue != nil) {
diff --git a/src/darwin/Framework/CHIP/MTRError.mm b/src/darwin/Framework/CHIP/MTRError.mm
index 00bd61d30bb995..4f907145ce5dcf 100644
--- a/src/darwin/Framework/CHIP/MTRError.mm
+++ b/src/darwin/Framework/CHIP/MTRError.mm
@@ -24,6 +24,8 @@
 #import <inet/InetError.h>
 #import <lib/support/TypeTraits.h>
 
+#import <objc/runtime.h>
+
 NSString * const MTRErrorDomain = @"MTRErrorDomain";
 
 NSString * const MTRInteractionErrorDomain = @"MTRInteractionErrorDomain";
@@ -47,6 +49,8 @@ + (NSError *)errorForCHIPErrorCode:(CHIP_ERROR)errorCode
         return nil;
     }
 
+    ChipLogError(Controller, "Creating NSError from %" CHIP_ERROR_FORMAT, errorCode.Format());
+
     if (errorCode.IsIMStatus()) {
         chip::app::StatusIB status(errorCode);
         return [MTRError errorForIMStatus:status];
@@ -94,10 +98,10 @@ + (NSError *)errorForCHIPErrorCode:(CHIP_ERROR)errorCode
         }];
     }
 
-    userInfo[@"underlyingError"] = [[MTRErrorHolder alloc] initWithError:errorCode];
-
-    return [NSError errorWithDomain:MTRErrorDomain code:code userInfo:userInfo];
-    ;
+    auto * error = [NSError errorWithDomain:MTRErrorDomain code:code userInfo:userInfo];
+    void * key = (__bridge void *) [MTRErrorHolder class];
+    objc_setAssociatedObject(error, key, [[MTRErrorHolder alloc] initWithError:errorCode], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+    return error;
 }
 
 + (NSError *)errorForIMStatus:(const chip::app::StatusIB &)status
@@ -237,8 +241,9 @@ + (CHIP_ERROR)errorToCHIPErrorCode:(NSError * _Nullable)error
         return CHIP_ERROR_INTERNAL;
     }
 
-    if (error.userInfo != nil) {
-        id underlyingError = error.userInfo[@"underlyingError"];
+    {
+        void * key = (__bridge void *) [MTRErrorHolder class];
+        id underlyingError = objc_getAssociatedObject(error, key);
         if (underlyingError != nil && [underlyingError isKindOfClass:[MTRErrorHolder class]]) {
             return ((MTRErrorHolder *) underlyingError).error;
         }