Proxing NSException stack trace to NSError object

Summary:
When we catch an Objective-C exception and convert it to NSError we need to somehow represent the call stack from NSException instance in NSError instance. For now, we just attach the stack trace to `message` field.

The next step would be to figure out how to pass the Objective-C stack trace to error reporting infra to help it to display the stack trace nicely in the web interface.

Changelog: [Internal] Fabric-specific internal change.

Reviewed By: sammy-SC

Differential Revision: D23557600

fbshipit-source-id: a080c2e186e719e42dcfc01bb12f5811e3c5b2e6

React/Base/RCTAssert.h

@@ -64,6 +64,11 @@ RCT_EXTERN NSString *const RCTJSStackTraceKey;
  */
 RCT_EXTERN NSString *const RCTJSRawStackTraceKey;
 
+/**
+ * Objective-C stack trace string provided as part of an NSError's userInfo
+ */
+RCT_EXTERN NSString *const RCTObjCStackTraceKey;
+
 /**
  * Name of fatal exceptions generated by RCTFatal
  */

React/Base/RCTAssert.m

@@ -11,6 +11,7 @@
 NSString *const RCTErrorDomain = @"RCTErrorDomain";
 NSString *const RCTJSStackTraceKey = @"RCTJSStackTraceKey";
 NSString *const RCTJSRawStackTraceKey = @"RCTJSRawStackTraceKey";
+NSString *const RCTObjCStackTraceKey = @"RCTObjCStackTraceKey";
 NSString *const RCTFatalExceptionName = @"RCTFatalException";
 NSString *const RCTUntruncatedMessageKey = @"RCTUntruncatedMessageKey";
 

React/Base/RCTUtils.h

@@ -98,6 +98,9 @@ RCT_EXTERN BOOL RCTForceTouchAvailable(void);
 // Create an NSError in the RCTErrorDomain
 RCT_EXTERN NSError *RCTErrorWithMessage(NSString *message);
 
+// Creates an NSError from given an NSException
+RCT_EXTERN NSError *RCTErrorWithNSException(NSException *exception);
+
 // Convert nil values to NSNull, and vice-versa
 #define RCTNullIfNil(value) ((value) ?: (id)kCFNull)
 #define RCTNilIfNull(value)                           \

React/Base/RCTUtils.m

@@ -581,6 +581,16 @@ BOOL RCTForceTouchAvailable(void)
   return [[NSError alloc] initWithDomain:RCTErrorDomain code:0 userInfo:errorInfo];
 }
 
+NSError *RCTErrorWithNSException(NSException *exception)
+{
+  NSString *message = [NSString stringWithFormat:@"NSException: %@; trace: %@.",
+                                                 exception,
+                                                 [[exception callStackSymbols] componentsJoinedByString:@";"]];
+  NSDictionary<NSString *, id> *errorInfo =
+      @{NSLocalizedDescriptionKey : message, RCTObjCStackTraceKey : [exception callStackSymbols]};
+  return [[NSError alloc] initWithDomain:RCTErrorDomain code:0 userInfo:errorInfo];
+}
+
 double RCTZeroIfNaN(double value)
 {
   return isnan(value) || isinf(value) ? 0 : value;

React/CxxModule/RCTCxxUtils.mm

@@ -74,8 +74,7 @@
       func();
       return nil;
     } @catch (NSException *exception) {
-      NSString *message = [NSString stringWithFormat:@"Exception '%@' was thrown from JS thread", exception];
-      return RCTErrorWithMessage(message);
+      return RCTErrorWithNSException(exception);
     } @catch (id exception) {
       // This will catch any other ObjC exception, but no C++ exceptions
       return RCTErrorWithMessage(@"non-std ObjC Exception");