fix(ios): Ensure duplicate native reports are discarded (#337)

If using `[BugsnagReactNative start]`, its possible that fatal JS
reports are sent despite the discard block if they fail to be filtered
before they are sent. This change moves the block to be called the first
time Bugsnag is started, in either layer.

Author: kattrali

CHANGELOG.md

@@ -1,6 +1,13 @@
 Changelog
 =========
 
+## TBD
+
+### Bug fixes
+
+* (iOS) Prevent delivering duplicate fatal JS crash reports when using enhanced
+  native integration.
+
 ## 2.16.0 (2019-04-04)
 
 * (Android) Upgrade to bugsnag-android v4.13.0

cocoa/BugsnagReactNative.m

@@ -99,6 +99,12 @@ BSGBreadcrumbType BreadcrumbTypeFromString(NSString *type) {
     return frames;
 }
 
+bool (^BSGReactNativeReportFilter)(NSDictionary *, BugsnagCrashReport *) = ^bool(NSDictionary *rawEventData,
+                                                                                 BugsnagCrashReport *_Nonnull report) {
+    return !([report.errorClass hasPrefix:@"RCTFatalException"]
+          && [report.errorMessage hasPrefix:@"Unhandled JS Exception"]);
+};
+
 @interface Bugsnag ()
 + (id)notifier;
 + (BOOL)bugsnagStarted;
@@ -121,10 +127,9 @@ + (void)start {
 }
 
 + (void)startWithAPIKey:(NSString *)APIKey {
-    if (APIKey.length == 0)
-        APIKey = [[NSBundle mainBundle] objectForInfoDictionaryKey:BSGInfoPlistKey];
-
-    [Bugsnag startBugsnagWithApiKey:APIKey];
+    BugsnagConfiguration *config = [BugsnagConfiguration new];
+    config.apiKey = APIKey;
+    [self startWithConfiguration:config];
 }
 
 + (void)startWithConfiguration:(BugsnagConfiguration *)config {
@@ -136,6 +141,7 @@ + (void)startWithConfiguration:(BugsnagConfiguration *)config {
     // way to interact with the application should instead leverage startSession
     // manually.
     config.shouldAutoCaptureSessions = NO;
+    [config addBeforeSendBlock:BSGReactNativeReportFilter];
     [Bugsnag startBugsnagWithConfiguration:config];
 }
 
@@ -265,12 +271,6 @@ + (void)startWithConfiguration:(BugsnagConfiguration *)config {
     config.shouldAutoCaptureSessions = [RCTConvert BOOL:options[@"autoCaptureSessions"]];
     config.automaticallyCollectBreadcrumbs = [RCTConvert BOOL:options[@"automaticallyCollectBreadcrumbs"]];
 
-    [config addBeforeSendBlock:^bool(NSDictionary *_Nonnull rawEventData,
-                                     BugsnagCrashReport *_Nonnull report) {
-        return !([report.errorClass hasPrefix:@"RCTFatalException"]
-                 && [report.errorMessage hasPrefix:@"Unhandled JS Exception"]);
-    }];
-
     if (notifyURLPath.length > 0) {
         [config setEndpointsForNotify:notifyURLPath
                              sessions:sessionURLPath];
@@ -284,9 +284,12 @@ + (void)startWithConfiguration:(BugsnagConfiguration *)config {
                             withValue:codeBundleId
                         toTabWithName:@"app"];
     }
-    if ([Bugsnag bugsnagStarted] && !config.autoNotify) {
-        bsg_kscrash_setHandlingCrashTypes(BSG_KSCrashTypeUserReported);
-    } else if (![Bugsnag bugsnagStarted]) {
+    if ([Bugsnag bugsnagStarted]) {
+        if (!config.autoNotify) {
+            bsg_kscrash_setHandlingCrashTypes(BSG_KSCrashTypeUserReported);
+        }
+    } else {
+        [config addBeforeSendBlock:BSGReactNativeReportFilter];
         [Bugsnag startBugsnagWithConfiguration:config];
     }
     [self setNotifierDetails:[RCTConvert NSString:options[@"version"]]];