ExceptionsManager: Report Fatal "Warnings"

Summary:
As suggested by motiz88 on D28421692 (883e0d5), make sure to still report fatal "warnings".

Changelog:
[General][Fixed] Report fatal errors even if its `type` is "warn".

Reviewed By: motiz88

Differential Revision: D28815228

fbshipit-source-id: 8d3b77958ef687a4ce64bdfccbf6ce2dc5557eaf

Libraries/Core/ExceptionsManager.js

@@ -112,7 +112,7 @@ function reportException(
       });
     }
 
-    if (e.type !== 'warn') {
+    if (isFatal || e.type !== 'warn') {
       NativeExceptionsManager.reportException(data);
 
       if (__DEV__ && !global.RN$Express) {

Libraries/Core/__tests__/ExceptionsManager-test.js

@@ -370,6 +370,15 @@ describe('ExceptionsManager', () => {
       expect(nativeReportException).toHaveBeenCalled();
     });
 
+    test('does not log "warn"-type errors', () => {
+      const error = new Error('This is a warning.');
+      error.type = 'warn';
+
+      console.error(error);
+
+      expect(nativeReportException).not.toHaveBeenCalled();
+    });
+
     test('reportErrorsAsExceptions = false', () => {
       console.reportErrorsAsExceptions = false;
       const message = 'Some error happened';
@@ -470,6 +479,15 @@ describe('ExceptionsManager', () => {
         "const error = new Error('Some error happened');",
       );
     });
+
+    test('logs fatal "warn"-type errors', () => {
+      const error = new Error('This is a fatal... warning?');
+      error.type = 'warn';
+
+      ExceptionsManager.handleException(error, true);
+
+      expect(nativeReportException).toHaveBeenCalled();
+    });
   });
 
   describe('unstable_setExceptionDecorator', () => {