I'm getting this while just importing nepali_date_picker package.

[codernirdesh]

Running flutter doctor... Doctor summary (to see all details, run flutter doctor -v): [✓] Flutter (Channel master, 2.3.0-1.0.pre.267, on Microsoft Windows [Version 10.0.19042.928], locale en-US) [✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3) [✓] Chrome - develop for the web [✓] Android Studio (version 4.1.0) [✓] VS Code (version 1.56.0) [✓] Connected device (3 available) • No issues found! Running "flutter pub get" in baigundhura_computer... 6.1s Launching lib\main.dart on BE2013 in debug mode... /C:/Users/Lenovo/AppData/Local/Pub/Cache/hosted/http://pub.dartlang.org/.../date_picker_dialog.dart:291:8: Error: A non-null value must be returned since the return type 'Size' doesn't allow null.

• 'Size' is from 'dart:ui'. Size _dialogSize(BuildContext context) { ^ /C:/Users/Lenovo/AppData/Local/Pub/Cache/hosted/http://pub.dartlang.org/.../date_picker_dialog.dart:447:24: Error: Final variable 'entryModeButton' must be assigned before it can be used. entryModeButton: entryModeButton, ^^^^^^^^^^^^^^^ /C:/Users/Lenovo/AppData/Local/Pub/Cache/hosted/http://pub.dartlang.org/.../date_picker_dialog.dart:470:39: Error: Non-nullable variable 'picker' must be assigned before it can be used. Expanded(child: picker), ^^^^^^ /C:/Users/Lenovo/AppData/Local/Pub/Cache/hosted/http://pub.dartlang.org/.../date_picker_dialog.dart:485:45: Error: Non-nullable variable 'picker' must be assigned before it can be used. Expanded(child: picker), ^^^^^^ /C:/Users/Lenovo/AppData/Local/Pub/Cache/hosted/http://pub.dartlang.org/.../date_range_picker_dialog.dart...: Error: Non-nullable variable 'size' must be assigned before it can be used. width: size.width, ^^^^ /C:/Users/Lenovo/AppData/Local/Pub/Cache/hosted/http://pub.dartlang.org/.../date_range_picker_dialog.dart...: Error: Non-nullable variable 'size' must be assigned before it can be used. height: size.height, ^^^^ /C:/Users/Lenovo/AppData/Local/Pub/Cache/hosted/http://pub.dartlang.org/.../date_range_picker_dialog.dart...: Error: Non-nullable variable 'contents' must be assigned before it can be used. return contents; ^^^^^^^^ /C:/Users/Lenovo/AppData/Local/Pub/Cache/hosted/http://pub.dartlang.org/.../date_range_picker_dialog.dart...: Error: Non-nullable variable 'insetPadding' must be assigned before it can be used. insetPadding: insetPadding, ^^^^^^^^^^^^ /C:/Users/Lenovo/AppData/Local/Pub/Cache/hosted/http://pub.dartlang.org/.../date_range_picker_dialog.dart...: Error: Non-nullable variable 'elevation' must be assigned before it can be used. elevation: elevation, ^^^^^^^^^ FAILURE: Build failed with an exception.
• Where: Script 'C:\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 1035
• What went wrong: Execution failed for task ':app:compileFlutterBuildDebug'.

  Process 'command 'C:\flutter\bin\flutter.bat'' finished with non-zero exit value 1

• Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
• Get more help at https://help.gradle.org BUILD FAILED in 1m 57s Running Gradle task 'assembleDebug'... 119.9s Exception: Gradle task assembleDebug failed with exit code 1

[sarbagyastha]

Current master has some breaking change, will soon release a dev version with the fix.