Flutter 2: problem in Intl null safety library
I upgrade my flutter sdk to flutter 2.0.0. After updating sdk I have changed almost all libraries to null safety version:
environment:
sdk: '>=2.12.0 <3.0.0'
dependencies:
flutter:
sdk: flutter
flutter_localizations:
sdk: flutter
cupertino_icons: ^0.1.3
encrypt: ^4.1.0
flutter_hooks: ^0.15.0
flutter_map: ^0.11.0
flutter_password_strength: ^0.1.5
flutter_svg: ^0.18.0
geolocator: ^7.0.1
get: ^3.25.6
get_it: ^6.0.0
injectable: ^1.1.2
local_auth: ^1.1.0
moor_flutter: ^3.1.0
provider: ^5.0.0
shared_preferences: ^2.0.3
supercharged: ^1.12.0
intl: ^0.17.0
after updating I run dart $ dart migrate
command. But It shows these problem about intl plugin:
Analyzing project...
[---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------/]
5 analysis issues found:
error • A value of type 'Null' can't be returned from the function '_findExact' because it has a return type of 'MessageLookupByLibrary' at lib/generated/intl/messages_all.dart:34:14 • (return_of_invalid_type)
error • A value of type 'Null' can't be returned from the function '_findGeneratedMessagesFor' because it has a return type of 'MessageLookupByLibrary' at lib/generated/intl/messages_all.dart:65:36 • (return_of_invalid_type)
error • Non-nullable instance field 'current' must be initialized at lib/generated/l10n.dart:16:3 • (not_initialized_non_nullable_instance_field)
error • The non-nullable variable 'current' must be initialized at lib/generated/l10n.dart:18:12 • (not_initialized_non_nullable_variable)
error • A value of type 'S?' can't be returned from the method 'of' because it has a return type of 'S' at lib/generated/l10n.dart:35:12 • (return_of_invalid_type)
The migration tool didn't start, due to analysis errors.
I am using last version of intl ? How can I fix that?
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 2.0.0, on Linux, locale en_US.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0-rc1)
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.0)
[✓] VS Code (version 1.53.2)
[✓] Connected device (2 available)
• No issues found!
I had the same issue. Here are 3 steps to troubleshoot this:
-
First of all, update
intl
dependency inpubspec.yaml
to this:intl: 0.17.0-nullsafety.2
-
If still doesn't work, then add these 2 fields in the root.
dependency_overrides: intl: 0.17.0-nullsafety.2
-
Generation also can happen via plugin in Android Studio. I used old one (v 0.12) and after I updated to (v 0.14) it started to generate null safety dart files for localization.
I think I stepped on every rock here.