[iOS] Reopening map offline throws exception from SQLite and breaks

[AAverin]

Neither onMapReady nor onStyleLoaded are not called when device is offline

[AAverin]

I suspect that style files are actually somewhere online and because in the implementation didFinishLoading style and not didFinishLoadingMap is used as a trigger that map is ready, if style is not accessible map is never ready in Flutter.

Is there a way to put styles offline too? Why doesn't this happen on Android?

Some logs that I get

2021-10-03 09:32:23.132188+0200 Runner[1843:2050389] Connection 117: received failure notification
2021-10-03 09:32:23.132224+0200 Runner[1843:2050389] Connection 117: failed to connect 1:50, reason -1
2021-10-03 09:32:23.132238+0200 Runner[1843:2050389] Connection 117: encountered error(1:50)
2021-10-03 09:32:23.132764+0200 Runner[1843:2050389] Task <5684C397-827F-4E36-8BE1-8183B6B5292F>.<11> HTTP load failed, 0/0 bytes (error code: -1009 [1:50])
2021-10-03 09:32:23.133185+0200 Runner[1843:2050391] Task <5684C397-827F-4E36-8BE1-8183B6B5292F>.<11> finished with error [-1009] Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." UserInfo={_kCFStreamErrorCodeKey=50, NSUnderlyingError=0x283ce7ab0 {Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_kCFStreamErrorCodeKey=50, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <5684C397-827F-4E36-8BE1-8183B6B5292F>.<11>, _NSURLErrorRelatedURLSessionTaskErrorKey=(
    "LocalDataTask <5684C397-827F-4E36-8BE1-8183B6B5292F>.<11>"
), NSLocalizedDescription=The Internet connection appears to be offline., NSErrorFailingURLStringKey=https://events.mapbox.com/events/v2?access_token=s..., NSErrorFailingURLKey=https://events.mapbox.com/events/v2?access_token=..., _kCFStreamErrorDomainKey=1}
2021-10-03 09:32:29.170930+0200 Runner[1843:2050389] Connection 118: received failure notification
2021-10-03 09:32:29.170973+0200 Runner[1843:2050389] Connection 118: failed to connect 1:50, reason -1
2021-10-03 09:32:29.171003+0200 Runner[1843:2050389] Connection 118: encountered error(1:50)
2021-10-03 09:32:29.172025+0200 Runner[1843:2050389] Task <0F420101-5251-48D3-98FE-2F920E68A9A5>.<108> HTTP load failed, 0/0 bytes (error code: -1009 [1:50])
2021-10-03 09:32:29.172229+0200 Runner[1843:2050389] Task <0F420101-5251-48D3-98FE-2F920E68A9A5>.<108> finished with error [-1009] Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." UserInfo={_kCFStreamErrorCodeKey=50, NSUnderlyingError=0x283ce2730 {Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_kCFStreamErrorCodeKey=50, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <0F420101-5251-48D3-98FE-2F920E68A9A5>.<108>, _NSURLErrorRelatedURLSessionTaskErrorKey=(
    "LocalDataTask <0F420101-5251-48D3-98FE-2F920E68A9A5>.<108>"
), NSLocalizedDescription=The Internet connection appears to be offline., NSErrorFailingURLStringKey=https://api.mapbox.com/styles/v1/mapbox/streets-v11?sku=100RqKiN39k2f64dae1bfc0b11ffe0564e296d139dc&access_token=..., NSErrorFailingURLKey=https://api.mapbox.com/styles/v1/mapbox/streets-v11?sku=100RqKiN39k2f64dae1bfc0b11ffe0564e296d139dc&access_token=..., _kCFStreamErrorDomainKey=1}
2021-10-03 09:32:30.183758+0200 Runner[1843:2050389] Connection 119: received failure notification
2021-10-03 09:32:30.184189+0200 Runner[1843:2050389] Connection 119: failed to connect 1:50, reason -1
2021-10-03 09:32:30.184308+0200 Runner[1843:2050389] Connection 119: encountered error(1:50)
2021-10-03 09:32:30.186569+0200 Runner[1843:2054072] Task <C1B164E1-921A-4EC9-987B-F867E39F8723>.<109> HTTP load failed, 0/0 bytes (error code: -1009 [1:50])
2021-10-03 09:32:30.187461+0200 Runner[1843:2050389] Task <C1B164E1-921A-4EC9-987B-F867E39F8723>.<109> finished with error [-1009] Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." UserInfo={_kCFStreamErrorCodeKey=50, NSUnderlyingError=0x283ca91d0 {Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_kCFStreamErrorCodeKey=50, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <C1B164E1-921A-4EC9-987B-F867E39F8723>.<109>, _NSURLErrorRelatedURLSessionTaskErrorKey=(
    "LocalDataTask <C1B164E1-921A-4EC9-987B-F867E39F8723>.<109>"
), NSLocalizedDescription=The Internet connection appears to be offline., NSErrorFailingURLStringKey=https://api.mapbox.com/styles/v1/mapbox/streets-v11?sku=100RqKiN39k2f64dae1bfc0b11ffe0564e296d139dc&access_token=..., NSErrorFailingURLKey=https://api.mapbox.com/styles/v1/mapbox/streets-v11?sku=100RqKiN39k2f64dae1bfc0b11ffe0564e296d139dc&access_token=..., _kCFStreamErrorDomainKey=1}
2021-10-03 09:32:32.199082+0200 Runner[1843:2050389] Connection 120: received failure notification
2021-10-03 09:32:32.199245+0200 Runner[1843:2050389] Connection 120: failed to connect 1:50, reason -1
2021-10-03 09:32:32.199347+0200 Runner[1843:2050389] Connection 120: encountered error(1:50)
2021-10-03 09:32:32.202032+0200 Runner[1843:2050389] Task <487B69EE-224B-42B0-8E95-41AFCCA7E7A7>.<110> HTTP load failed, 0/0 bytes (error code: -1009 [1:50])
2021-10-03 09:32:32.202822+0200 Runner[1843:2050389] Task <487B69EE-224B-42B0-8E95-41AFCCA7E7A7>.<110> finished with error [-1009] Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." UserInfo={_kCFStreamErrorCodeKey=50, NSUnderlyingError=0x283cafdb0 {Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_kCFStreamErrorCodeKey=50, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <487B69EE-224B-42B0-8E95-41AFCCA7E7A7>.<110>, _NSURLErrorRelatedURLSessionTaskErrorKey=(
    "LocalDataTask <487B69EE-224B-42B0-8E95-41AFCCA7E7A7>.<110>"
), NSLocalizedDescription=The Internet connection appears to be offline., NSErrorFailingURLStringKey=https://api.mapbox.com/styles/v1/mapbox/streets-v11?sku=100RqKiN39k2f64dae1bfc0b11ffe0564e296d139dc&access_token=..., NSErrorFailingURLKey=https://api.mapbox.com/styles/v1/mapbox/streets-v11?sku=100RqKiN39k2f64dae1bfc0b11ffe0564e296d139dc&access_token=..., _kCFStreamErrorDomainKey=1}
2021-10-03 09:32:36.212156+0200 Runner[1843:2054071] Connection 121: received failure notification
2021-10-03 09:32:36.212295+0200 Runner[1843:2054071] Connection 121: failed to connect 1:50, reason -1
2021-10-03 09:32:36.212399+0200 Runner[1843:2054071] Connection 121: encountered error(1:50)
2021-10-03 09:32:36.214260+0200 Runner[1843:2054072] Task <9E16A306-93AC-44B2-9C9C-2C5A56FEB2CF>.<111> HTTP load failed, 0/0 bytes (error code: -1009 [1:50])
2021-10-03 09:32:36.215052+0200 Runner[1843:2054072] Task <9E16A306-93AC-44B2-9C9C-2C5A56FEB2CF>.<111> finished with error [-1009] Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." UserInfo={_kCFStreamErrorCodeKey=50, NSUnderlyingError=0x283caad00 {Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_kCFStreamErrorCodeKey=50, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <9E16A306-93AC-44B2-9C9C-2C5A56FEB2CF>.<111>, _NSURLErrorRelatedURLSessionTaskErrorKey=(
    "LocalDataTask <9E16A306-93AC-44B2-9C9C-2C5A56FEB2CF>.<111>"
), NSLocalizedDescription=The Internet connection appears to be offline., NSErrorFailingURLStringKey=https://api.mapbox.com/styles/v1/mapbox/streets-v11?sku=100RqKiN39k2f64dae1bfc0b11ffe0564e296d139dc&access_token=..., NSErrorFailingURLKey=https://api.mapbox.com/styles/v1/mapbox/streets-v11?sku=100RqKiN39k2f64dae1bfc0b11ffe0564e296d139dc&access_token=..., _kCFStreamErrorDomainKey=1}

[AAverin]

The style itself is, of course, bundled into the offline package and should be used by default instead of loading it from the network and failing.
And it seems to be used the first time map is opened, but every subsequent opening results in error

[AAverin]

The reason behind is a leak. I will continue investigation if it's in my codebase or in mapbox for ios

[AAverin]

#389

[AAverin]

Fixing the leaks, it doesn't seem to be related.

[AAverin]

The first start of the map, when offline map loads correctly, the errors look like

mapViewDidFailLoadingMap Error Domain=MGLErrorDomain Code=-1 "The map failed to load because an unknown error occurred." UserInfo={NSLocalizedDescription=The map failed to load because an unknown error occurred., NSLocalizedFailureReason=Failed to load tile 2/2/0=>2 for source composite: The Internet connection appears to be offline.}

The second start of the screen with the map, when offline map does not display anymore correctly, errors look like:

mapViewDidFailLoadingMap Error Domain=MGLErrorDomain Code=5 "The map failed to load because the style can't be loaded." UserInfo={NSLocalizedDescription=The map failed to load because the style can't be loaded., NSLocalizedFailureReason=loading style failed: The Internet connection appears to be offline.}

Nothing changes between two screens, second screen with the map just doesn't work because it can't load style even though it's already bundled into the map database that was side-loaded.

@m0nac0 Do you have any iOS knowledge or maybe ideas why this could be happening?

[m0nac0]

Unfortunately, my iOS dev knowledge is very limited, so I'm afraid I don't have an idea of what is going on here.

@TimothySealy wrote a lot of the iOS code for this plugin, maybe he has got an idea?

[AAverin]

I have also noticed this in logs

[logging] BUG IN CLIENT OF libsqlite3.dylib: database integrity compromised by API violation: vnode unlinked while in use: /private/var/mobile/Containers/Data/Application/E9F89FE6-3545-416A-A344-313E5A65A875/Library/Application Support/___/.mapbox/cache.db
[logging] invalidated open fd: 48 (0x11)

[AAverin]

This gets outputed on second call to installOfflineMapTiles method.
@TimothySealy I would really appreciate some help or input on this ticket, offline support is critical for my project release and it's the last thing that needs fixing before I can roll out the app to customers.

[AAverin]

I have also opened mapbox/mapbox-gl-native-ios#637 because it's highly likely issue is somewhere in original Mapbox-iOS SDK

[AAverin]

It looks like original mapbox-gl-native-ios SDK is not in active development for the last 2 years, they have probably been working on new v10 implementation

[raphaaugustosilva]

@AAverin how did you managed to workaround this situation?
I need to initialize mapbox map when offline too.

[AAverin]

@raphaaugustosilva I didn't.
I created mapbox/mapbox-gl-native-ios#637 for the original mapbox ios SDK because the error is coming from it, so it's likely that cause is also inside original SDK. Didn't get any response there yet.

Another theoretical possibility are memory leaks that are now investigated in
#706 and #710
flutter/flutter#91508 is tracking leaks in flutter engine itself.

All in all, I don't know how to solve this problem yet. Some input of experienced iOS developer is needed here.

@raphaaugustosilva If you will manage to reproduce the issue using original Mapbox iOS SDK sample app and post the example here, it would help greately with investigation

[raphaaugustosilva]

@AAverin thanks!
Unfortunately, I am only going to use Mapbox using Flutter (Android and iOS), but my core is to work offline.

I also tried to download offline region in background with internet before opening the map for the first time without internet (using flutter mapbox downloadOfflineRegion method), but the error is the same.

Thanks for the inputs, I`ll subscribe here in order to get more updates.