Empty defaultSettings breaks event reporting

[leethree]

We found there is major data discrepancy between our Android and iOS app using Segment and some iOS clients don't report any data to Segment. After investigation, we found that the library will not report any events if the first call to cdn-settings.segment.com fails.

We are using analytics-react-native and it passes an empty dict for defaultSettings.

https://github.com/segmentio/analytics-react-native/blob/9b5734d58b3f4099b5396504debb4ffad2abdd79/packages/core/src/configuration.ts#L29

This breaks the fallback logic of the library settings because here the code only checks for nil.

analytics-ios/Segment/Internal/SEGIntegrationsManager.m

Lines 463 to 470 in 9cab023

	} else if (self.configuration.defaultSettings != nil) {
	// If settings request fail, load a user-supplied version if present.
	// but make sure segment.io is in the integrations
	NSMutableDictionary *newSettings = [self.configuration.defaultSettings serializableMutableDeepCopy];
	newSettings[@"integrations"][@"Segment.io"][@"apiKey"] = self.configuration.writeKey;
	[self setCachedSettings:newSettings];
	// don't configure edge functions here. it'll do the right thing on it's own.
	} else {

newSettings[@"integrations"][@"Segment.io"][@"apiKey"] doesn't do anything because the keys don't exist. This results in an empty setting cached in the client and no events will be send to Segment.io because the integration is not enabled.

No settings for Segment.io. Skipping.

[bsneed]

Will have a look into this today.

[bsneed]

Fixed in PR #973. If any other details come up, please reopen this issue. Thanks so much for the report!!