Null check operator call on null when update table

[mdat31]

I've made some changes in a table, changes name, add some column, remove some, etc...

When i run on emulator it's run fine. But on real device i receive null check operator use on null

I clean everything, uninstall app and reinstall, delete .g file and build again but no use

[simolus3]

After changing tables (especially when adding columns), you need to write a schema migration responsible for writing theses changes to an existing database. Otherwise, moor will expect columns that aren't there, which can cause the error you received. There will be similar errors when inserting new rows into a database that doesn't have the updated columns yet.

If you don't want to do that, and you haven't released your app to actual users yet, you can delete your app's data on the real device and install it again.

[mdat31]

My app haven't released yet, i've tried delete app and clear data without deleting app on real device and still got that error.
My device is Xiaomi Redmi 6A.

[simolus3]

Maybe the device somehow restores data across installations? I have seen that in the past. Can you post the stack trace of that error? If it happens when reading rows in a select statement, the database is probably still there.

[mdat31]

Yes, it happens when i use select statement.

Is this the stack trace you need?

E/flutter ( 5547): [ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: Null check operator used on a null value
E/flutter ( 5547): #0      new DownloadedChapter.fromData (package:manga_one/main/data/datasources/local/moor_manga/moor_manga_database.g.dart:654:67)
E/flutter ( 5547): #1      $DownloadedChaptersTable.map (package:manga_one/main/data/datasources/local/moor_manga/moor_manga_database.g.dart:1158:30)
E/flutter ( 5547): #2      MappedListIterable.elementAt (dart:_internal/iterable.dart:412:31)
E/flutter ( 5547): #3      ListIterator.moveNext (dart:_internal/iterable.dart:341:26)
E/flutter ( 5547): #4      new _GrowableList._ofEfficientLengthIterable (dart:core-patch/growable_array.dart:188:27)
E/flutter ( 5547): #5      new _GrowableList.of (dart:core-patch/growable_array.dart:150:28)
E/flutter ( 5547): #6      new List.of (dart:core-patch/array_patch.dart:50:28)
E/flutter ( 5547): #7      ListIterable.toList (dart:_internal/iterable.dart:212:44)
E/flutter ( 5547): #8      SimpleSelectStatement._mapResponse (package:moor/src/runtime/query_builder/statements/select/select.dart:73:32)
E/flutter ( 5547): #9      _MapStream._handleData (dart:async/stream_pipe.dart:213:31)
E/flutter ( 5547): #10     _ForwardingStreamSubscription._handleData (dart:async/stream_pipe.dart:153:13)
E/flutter ( 5547): #11     _StartWithValueSubscription._wrappedDataCallback.<anonymous closure> (package:moor/src/utils/start_with_value_transformer.dart:70:15)
E/flutter ( 5547): #12     _rootRunUnary (dart:async/zone.dart:1362:47)
E/flutter ( 5547): #13     _CustomZone.runUnary (dart:async/zone.dart:1265:19)
E/flutter ( 5547): #14     _CustomZone.runUnaryGuarded (dart:async/zone.dart:1170:7)
E/flutter ( 5547): #15     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
E/flutter ( 5547): #16     _DelayedData.perform (dart:async/stream_impl.dart:591:14)
E/flutter ( 5547): #17     _StreamImplEvents.handleNext (dart:async/stream_impl.dart:706:11)
E/flutter ( 5547): #18     _PendingEvents.schedule.<anonymous closure> (dart:async/stream_impl.dart:663:7)
E/flutter ( 5547): #19     _rootRun (dart:async/zone.dart:1346:47)
E/flutter ( 5547): #20     _CustomZone.run (dart:async/zone.dart:1258:19)
E/flutter ( 5547): #21     _CustomZone.runGuarded (dart:async/zone.dart:1162:7)
E/flutter ( 5547): #22     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1202:23)
E/flutter ( 5547): #23     _rootRun (dart:async/zone.dart:1354:13)
E/flutter ( 5547): #24     _CustomZone.run (dart:async/zone.dart:1258:19)
E/flutter ( 5547): #25     _CustomZone.runGuarded (dart:async/zone.dart:1162:7)
E/flutter ( 5547): #26     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1202:23)
E/flutter ( 5547): #27     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
E/flutter ( 5547): #28     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
E/flutter ( 5547): 
E/flutter ( 5547): [ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: Null check operator used on a null value
E/flutter ( 5547): #0      new DownloadedChapter.fromData (package:manga_one/main/data/datasources/local/moor_manga/moor_manga_database.g.dart:654:67)
E/flutter ( 5547): #1      $DownloadedChaptersTable.map (package:manga_one/main/data/datasources/local/moor_manga/moor_manga_database.g.dart:1158:30)
E/flutter ( 5547): #2      MappedListIterable.elementAt (dart:_internal/iterable.dart:412:31)
E/flutter ( 5547): #3      ListIterator.moveNext (dart:_internal/iterable.dart:341:26)
E/flutter ( 5547): #4      new _GrowableList._ofEfficientLengthIterable (dart:core-patch/growable_array.dart:188:27)
E/flutter ( 5547): #5      new _GrowableList.of (dart:core-patch/growable_array.dart:150:28)
E/flutter ( 5547): #6      new List.of (dart:core-patch/array_patch.dart:50:28)
E/flutter ( 5547): #7      ListIterable.toList (dart:_internal/iterable.dart:212:44)
E/flutter ( 5547): #8      SimpleSelectStatement._mapResponse (package:moor/src/runtime/query_builder/statements/select/select.dart:73:32)
E/flutter ( 5547): #9      _MapStream._handleData (dart:async/stream_pipe.dart:213:31)
E/flutter ( 5547): #10     _ForwardingStreamSubscription._handleData (dart:async/stream_pipe.dart:153:13)
E/flutter ( 5547): #11     _StartWithValueSubscription._wrappedDataCallback.<anonymous closure> (package:moor/src/utils/start_with_value_transformer.dart:70:15)
E/flutter ( 5547): #12     _rootRunUnary (dart:async/zone.dart:1362:47)
E/flutter ( 5547): #13     _CustomZone.runUnary (dart:async/zone.dart:1265:19)
E/flutter ( 5547): #14     _CustomZone.runUnaryGuarded (dart:async/zone.dart:1170:7)
E/flutter ( 5547): #15     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
E/flutter ( 5547): #16     _DelayedData.perform (dart:async/stream_impl.dart:591:14)
E/flutter ( 5547): #17     _StreamImplEvents.handleNext (dart:async/stream_impl.dart:706:11)
E/flutter ( 5547): #18     _PendingEvents.schedule.<anonymous closure> (dart:async/stream_impl.dart:663:7)
E/flutter ( 5547): #19     _rootRun (dart:async/zone.dart:1346:47)
E/flutter ( 5547): #20     _CustomZone.run (dart:async/zone.dart:1258:19)
E/flutter ( 5547): #21     _CustomZone.runGuarded (dart:async/zone.dart:1162:7)
E/flutter ( 5547): #22     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1202:23)
E/flutter ( 5547): #23     _rootRun (dart:async/zone.dart:1354:13)
E/flutter ( 5547): #24     _CustomZone.run (dart:async/zone.dart:1258:19)
E/flutter ( 5547): #25     _CustomZone.runGuarded (dart:async/zone.dart:1162:7)
E/flutter ( 5547): #26     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1202:23)
E/flutter ( 5547): #27     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
E/flutter ( 5547): #28     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)

[simolus3]

I'm still convinced that this is about existing data on the device which is missing some columns.

Inside your app, you could try to delete the database file before opening it (just once for testing). Does that fix the problem on the real device?

[mdat31]

I delete it with file.delete on db file and it works. Thanks!