Another newb with null sound problems

I managed to install aqueduct a couple of weeks ago, had to do some work arounds but it was all working (aqueduct serve, aqueduct db generate).

Then I ran into a weird problem, and reinstalled flutter and dart sdk. Offcourse aqueduct stopped in its tracks. So i am trying to get my backend working again. I think I had a seperate dart running and currently dar is installed with flutter.

dart version: Dart SDK version: 2.12.0-133.7.beta (beta) (Tue Jan 12 09:25:38 2021 +0100) on "windows_x64"

I tried cloning aqueduct repo locally and pub global activate --source and this is in my pubspec.yaml

dependency_overrides:
  aqueduct:
    path:  C:\src\s\aqueduct\aqueduct
  aqueduct_test:
    path:  C:\src\s\aqueduct\aqueduct_test\

then pub run aqueduct serve:


`PS D:\projects\spur\backend> pub run aqueduct serve
-- Aqueduct CLI Version: 4.0.0-b1
-- Aqueduct project version: 4.0.0-b1
-- Preparing...
data:application/dart;charset=utf-8,import%20'dart%3Aasync'%3B%0Aimport%20'dart%3Aisolate'%3B%0Aimport%20'dart%3Amirrors'%3B%0Aimport%20'package%3Aaqueduct%2Faqueduct.dart'%3B%0Aimport%20'package%3Adart_server%2Fdart_server.dart'%3B%0Aimport%20'package%3Aruntime%2Fruntime.dart'%3B%0AFuture%20main%20(List%3CString%3E%20args%2C%20Map%3CString%2C%20dynamic%3E%20message)%20async%20%7B%0A%20%20final%20sendPort%20%3D%20message%5B'_sendPort'%5D%3B%0A%20%20final%20executable%20%3D%20new%20GetChannelExecutable(message)%3B%0A%20%20final%20result%20%3D%20await%20executable.execute()%3B%0A%20%20sendPort.send(%7B%22_result%22%3A%20result%7D)%3B%0A%7D%0A%20%20%20%20%0Aclass%20GetChannelExecutable%20extends%20Executable%3CString%3E%20%7BGetChannelExecutable(Map%3CString%2C%20dynamic%3E%20message)%20%3A%20super(message)%3B%20%40override%20Future%3CString%3E%20execute()%20async%20%7Bfinal%20channels%20%3D%20RuntimeContext.current.runtimes.iterable.whereType%3CChannelRuntime%3E()%3B%20if%20(channels.length%20!%3D%201)%20%7Bthrow%20StateError(%22No%20ApplicationChannel%20subclass%20was%20found%20for%20this%20project.%20%22%20%22Make%20sure%20it%20is%20imported%20in%20your%20application%20library%20file.%22)%3B%7D%20var%20runtime%20%3D%20channels.first%3B%20if%20(runtime%20%3D%3D%20null)%20%7Breturn%20null%3B%7D%20return%20MirrorSystem.getName(reflectClass(runtime.channelType).simpleName)%3B%7D%20static%20List%3CString%3E%20importsForPackage(String%20packageName)%20%3D%3E%20%5B%22package%3Aaqueduct%2Faqueduct.dart%22%2C%20%22package%3A%24packageName%2F%24packageName.dart%22%2C%20%22package%3Aruntime%2Fruntime.dart%22%5D%3B%7D%0Aabstract%20class%20Executable%3CT%3E%20%7BExecutable(this.message)%20%3A%20_sendPort%20%3D%20message%5B%22_sendPort%22%5D%3B%20Future%3CT%3E%20execute()%3B%20final%20Map%3CString%2C%20dynamic%3E%20message%3B%20final%20SendPort%20_sendPort%3B%20U%20instanceOf%3CU%3E(String%20typeName%2C%20%7BList%20positionalArguments%3A%20const%20%5B%5D%2C%20Map%3CSymbol%2C%20dynamic%3E%20namedArguments%2C%20Symbol%20constructorName%7D)%20%7BClassMirror%20typeMirror%20%3D%20currentMirrorSystem().isolate.rootLibrary.declarations%5Bnew%20Symbol(typeName)%5D%3B%20if%20(typeMirror%20%3D%3D%20null)%20%7BtypeMirror%20%3D%20currentMirrorSystem().libraries.values.where((lib)%20%3D%3E%20lib.uri.scheme%20%3D%3D%20%22package%22%20%7C%7C%20lib.uri.scheme%20%3D%3D%20%22file%22).expand((lib)%20%3D%3E%20lib.declarations.values).firstWhere((decl)%20%3D%3E%20decl%20is%20ClassMirror%20%26%26%20MirrorSystem.getName(decl.simpleName)%20%3D%3D%20typeName%2C%20orElse%3A%20()%20%3D%3E%20throw%20new%20ArgumentError(%22Unknown%20type%20'%24typeName'.%20Did%20you%20forget%20to%20import%20it%3F%22))%3B%7D%20return%20typeMirror.newInstance(constructorName%20%3F%3F%20const%20Symbol(%22%22)%2C%20positionalArguments%2C%20namedArguments).reflectee%20as%20U%3B%7D%20void%20send(dynamic%20message)%20%7B_sendPort.send(message)%3B%7D%20void%20log(String%20message)%20%7B_sendPort.send(%7B%22_line_%22%20%3A%20message%7D)%3B%7D%7D%0A:15:825: Warning: Operand of null-aware operation '??' has type 'Symbol' which excludes null.
 - 'Symbol' is from 'dart:core'.
abstract class Executable<T> {Executable(this.message) : _sendPort = message["_sendPort"]; Future<T> execute(); final Map<String, dynamic> message; final SendPort _sendPort; U instanceOf<U>(String typeName, {List positionalArguments: const [], Map<Symbol, dynamic> namedArguments, Symbol constructorName}) {ClassMirror typeMirror = currentMirrorSystem().isolate.rootLibrary.declarations[new Symbol(typeName)]; if (typeMirror == null) {typeMirror = currentMirrorSystem().libraries.values.where((lib) => lib.uri.scheme == "package" || lib.uri.scheme == "file").expand((lib) => lib.declarations.values).firstWhere((decl) => decl is ClassMirror && MirrorSystem.getName(decl.simpleName) == typeName, orElse: () => throw new ArgumentError("Unknown type '$typeName'. Did you forget to import it?"));} return typeMirror.newInstance(constructorName ?? const Symbol(""), positionalArguments, namedArguments).reflectee as U;} void send(dynamic message) {_sendPort.send(message);} void log(String message) {_sendPort.send({"_line_" : message});}}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        ^
*** Uncaught error
    IsolateSpawnException: Unable to spawn isolate: Error: Cannot run with sound null safety, because the following dependencies
don't support null safety:

 - package:aqueduct
 - package:dart_server
 - package:runtime
 - package:logging
 - package:safe_config
 - package:crypto
 - package:password_hash
 - package:open_api
 - package:analyzer
 - package:meta
 - package:pubspec_parse
 - package:yaml
 - package:isolate_executor
 - package:postgres
 - package:path
 - package:watcher
 - package:collection
 - package:convert
 - package:codable
 - package:cli_util
 - package:pub_semver
 - package:_fe_analyzer_shared
 - package:json_annotation
 - package:checked_yaml
 - package:charcode
 - package:source_span
 - package:typed_data
 - package:buffer
 - package:pedantic
 - package:string_scanner
 - package:glob
 - package:args
 - package:async
 - package:term_glyph
 - package:package_config

For solutions, see https://dart.dev/go/unsound-null-safety
data:application/dart;charset=utf-8,import%20'dart%3Aasync'%3B%0Aimport%20'dart%3Aisolate'%3B%0Aimport%20'dart%3Amirrors'%3B%0Aimport%20'package%3Aaqueduct%2Faqueduct.dart'%3B%0Aimport%20'package%3Adart_server%2Fdart_server.dart'%3B%0Aimport%20'package%3Aruntime%2Fruntime.dart'%3B%0AFuture%20main%20(List%3CString%3E%20args%2C%20Map%3CString%2C%20dynamic%3E%20message)%20async%20%7B%0A%20%20final%20sendPort%20%3D%20message%5B'_sendPort'%5D%3B%0A%20%20final%20executable%20%3D%20new%20GetChannelExecutable(message)%3B%0A%20%20final%20result%20%3D%20await%20executable.execute()%3B%0A%20%20sendPort.send(%7B%22_result%22%3A%20result%7D)%3B%0A%7D%0A%20%20%20%20%0Aclass%20GetChannelExecutable%20extends%20Executable%3CString%3E%20%7BGetChannelExecutable(Map%3CString%2C%20dynamic%3E%20message)%20%3A%20super(message)%3B%20%40override%20Future%3CString%3E%20execute()%20async%20%7Bfinal%20channels%20%3D%20RuntimeContext.current.runtimes.iterable.whereType%3CChannelRuntime%3E()%3B%20if%20(channels.length%20!%3D%201)%20%7Bthrow%20StateError(%22No%20ApplicationChannel%20subclass%20was%20found%20for%20this%20project.%20%22%20%22Make%20sure%20it%20is%20imported%20in%20your%20application%20library%20file.%22)%3B%7D%20var%20runtime%20%3D%20channels.first%3B%20if%20(runtime%20%3D%3D%20null)%20%7Breturn%20null%3B%7D%20return%20MirrorSystem.getName(reflectClass(runtime.channelType).simpleName)%3B%7D%20static%20List%3CString%3E%20importsForPackage(String%20packageName)%20%3D%3E%20%5B%22package%3Aaqueduct%2Faqueduct.dart%22%2C%20%22package%3A%24packageName%2F%24packageName.dart%22%2C%20%22package%3Aruntime%2Fruntime.dart%22%5D%3B%7D%0Aabstract%20class%20Executable%3CT%3E%20%7BExecutable(this.message)%20%3A%20_sendPort%20%3D%20message%5B%22_sendPort%22%5D%3B%20Future%3CT%3E%20execute()%3B%20final%20Map%3CString%2C%20dynamic%3E%20message%3B%20final%20SendPort%20_sendPort%3B%20U%20instanceOf%3CU%3E(String%20typeName%2C%20%7BList%20positionalArguments%3A%20const%20%5B%5D%2C%20Map%3CSymbol%2C%20dynamic%3E%20namedArguments%2C%20Symbol%20constructorName%7D)%20%7BClassMirror%20typeMirror%20%3D%20currentMirrorSystem().isolate.rootLibrary.declarations%5Bnew%20Symbol(typeName)%5D%3B%20if%20(typeMirror%20%3D%3D%20null)%20%7BtypeMirror%20%3D%20currentMirrorSystem().libraries.values.where((lib)%20%3D%3E%20lib.uri.scheme%20%3D%3D%20%22package%22%20%7C%7C%20lib.uri.scheme%20%3D%3D%20%22file%22).expand((lib)%20%3D%3E%20lib.declarations.values).firstWhere((decl)%20%3D%3E%20decl%20is%20ClassMirror%20%26%26%20MirrorSystem.getName(decl.simpleName)%20%3D%3D%20typeName%2C%20orElse%3A%20()%20%3D%3E%20throw%20new%20ArgumentError(%22Unknown%20type%20'%24typeName'.%20Did%20you%20forget%20to%20import%20it%3F%22))%3B%7D%20return%20typeMirror.newInstance(constructorName%20%3F%3F%20const%20Symbol(%22%22)%2C%20positionalArguments%2C%20namedArguments).reflectee%20as%20U%3B%7D%20void%20send(dynamic%20message)%20%7B_sendPort.send(message)%3B%7D%20void%20log(String%20message)%20%7B_sendPort.send(%7B%22_line_%22%20%3A%20message%7D)%3B%7D%7D%0A:15:266: Error: The parameter 'namedArguments' can't have a value of 'null' because of its type 'Map<Symbol, dynamic>', but the implicit default value is 'null'.
 - 'Map' is from 'dart:core'.
 - 'Symbol' is from 'dart:core'.
Try adding either an explicit non-'null' default value or the 'required' modifier.
abstract class Executable<T> {Executable(this.message) : _sendPort = message["_sendPort"]; Future<T> execute(); final Map<String, dynamic> message; final SendPort _sendPort; U instanceOf<U>(String typeName, {List positionalArguments: const [], Map<Symbol, dynamic> namedArguments, Symbol constructorName}) {ClassMirror typeMirror = currentMirrorSystem().isolate.rootLibrary.declarations[new Symbol(typeName)]; if (typeMirror == null) {typeMirror = currentMirrorSystem().libraries.values.where((lib) => lib.uri.scheme == "package" || lib.uri.scheme == "file").expand((lib) => lib.declarations.values).firstWhere((decl) => decl is ClassMirror && MirrorSystem.getName(decl.simpleName) == typeName, orElse: () => throw new ArgumentError("Unknown type '$typeName'. Did you forget to import it?"));} return typeMirror.newInstance(constructorName ?? const Symbol(""), positionalArguments, namedArguments).reflectee as U;} void send(dynamic message) {_sendPort.send(message);} void log(String message) {_sendPort.send({"_line_" : message});}}
                                                                                                                                                                                                                                                                         ^^^^^^^^^^^^^^
data:application/dart;charset=utf-8,import%20'dart%3Aasync'%3B%0Aimport%20'dart%3Aisolate'%3B%0Aimport%20'dart%3Amirrors'%3B%0Aimport%20'package%3Aaqueduct%2Faqueduct.dart'%3B%0Aimport%20'package%3Adart_server%2Fdart_server.dart'%3B%0Aimport%20'package%3Aruntime%2Fruntime.dart'%3B%0AFuture%20main%20(List%3CString%3E%20args%2C%20Map%3CString%2C%20dynamic%3E%20message)%20async%20%7B%0A%20%20final%20sendPort%20%3D%20message%5B'_sendPort'%5D%3B%0A%20%20final%20executable%20%3D%20new%20GetChannelExecutable(message)%3B%0A%20%20final%20result%20%3D%20await%20executable.execute()%3B%0A%20%20sendPort.send(%7B%22_result%22%3A%20result%7D)%3B%0A%7D%0A%20%20%20%20%0Aclass%20GetChannelExecutable%20extends%20Executable%3CString%3E%20%7BGetChannelExecutable(Map%3CString%2C%20dynamic%3E%20message)%20%3A%20super(message)%3B%20%40override%20Future%3CString%3E%20execute()%20async%20%7Bfinal%20channels%20%3D%20RuntimeContext.current.runtimes.iterable.whereType%3CChannelRuntime%3E()%3B%20if%20(channels.length%20!%3D%201)%20%7Bthrow%20StateError(%22No%20ApplicationChannel%20subclass%20was%20found%20for%20this%20project.%20%22%20%22Make%20sure%20it%20is%20imported%20in%20your%20application%20library%20file.%22)%3B%7D%20var%20runtime%20%3D%20channels.first%3B%20if%20(runtime%20%3D%3D%20null)%20%7Breturn%20null%3B%7D%20return%20MirrorSystem.getName(reflectClass(runtime.channelType).simpleName)%3B%7D%20static%20List%3CString%3E%20importsForPackage(String%20packageName)%20%3D%3E%20%5B%22package%3Aaqueduct%2Faqueduct.dart%22%2C%20%22package%3A%24packageName%2F%24packageName.dart%22%2C%20%22package%3Aruntime%2Fruntime.dart%22%5D%3B%7D%0Aabstract%20class%20Executable%3CT%3E%20%7BExecutable(this.message)%20%3A%20_sendPort%20%3D%20message%5B%22_sendPort%22%5D%3B%20Future%3CT%3E%20execute()%3B%20final%20Map%3CString%2C%20dynamic%3E%20message%3B%20final%20SendPort%20_sendPort%3B%20U%20instanceOf%3CU%3E(String%20typeName%2C%20%7BList%20positionalArguments%3A%20const%20%5B%5D%2C%20Map%3CSymbol%2C%20dynamic%3E%20namedArguments%2C%20Symbol%20constructorName%7D)%20%7BClassMirror%20typeMirror%20%3D%20currentMirrorSystem().isolate.rootLibrary.declarations%5Bnew%20Symbol(typeName)%5D%3B%20if%20(typeMirror%20%3D%3D%20null)%20%7BtypeMirror%20%3D%20currentMirrorSystem().libraries.values.where((lib)%20%3D%3E%20lib.uri.scheme%20%3D%3D%20%22package%22%20%7C%7C%20lib.uri.scheme%20%3D%3D%20%22file%22).expand((lib)%20%3D%3E%20lib.declarations.values).firstWhere((decl)%20%3D%3E%20decl%20is%20ClassMirror%20%26%26%20MirrorSystem.getName(decl.simpleName)%20%3D%3D%20typeName%2C%20orElse%3A%20()%20%3D%3E%20throw%20new%20ArgumentError(%22Unknown%20type%20'%24typeName'.%20Did%20you%20forget%20to%20import%20it%3F%22))%3B%7D%20return%20typeMirror.newInstance(constructorName%20%3F%3F%20const%20Symbol(%22%22)%2C%20positionalArguments%2C%20namedArguments).reflectee%20as%20U%3B%7D%20void%20send(dynamic%20message)%20%7B_sendPort.send(message)%3B%7D%20void%20log(String%20message)%20%7B_sendPort.send(%7B%22_line_%22%20%3A%20message%7D)%3B%7D%7D%0A:15:289: Error: The parameter 'constructorName' can't have a value of 'null' because of its type 'Symbol', but the implicit default value is 'null'.
 - 'Symbol' is from 'dart:core'.
Try adding either an explicit non-'null' default value or the 'required' modifier.
abstract class Executable<T> {Executable(this.message) : _sendPort = message["_sendPort"]; Future<T> execute(); final Map<String, dynamic> message; final SendPort _sendPort; U instanceOf<U>(String typeName, {List positionalArguments: const [], Map<Symbol, dynamic> namedArguments, Symbol constructorName}) {ClassMirror typeMirror = currentMirrorSystem().isolate.rootLibrary.declarations[new Symbol(typeName)]; if (typeMirror == null) {typeMirror = currentMirrorSystem().libraries.values.where((lib) => lib.uri.scheme == "package" || lib.uri.scheme == "file").expand((lib) => lib.declarations.values).firstWhere((decl) => decl is ClassMirror && MirrorSystem.getName(decl.simpleName) == typeName, orElse: () => throw new ArgumentError("Unknown type '$typeName'. Did you forget to import it?"));} return typeMirror.newInstance(constructorName ?? const Symbol(""), positionalArguments, namedArguments).reflectee as U;} void send(dynamic message) {_sendPort.send(message);} void log(String message) {_sendPort.send({"_line_" : message});}}
                                                                                                                                                                                                                                                                                                ^^^^^^^^^^^^^^^
data:application/dart;charset=utf-8,import%20'dart%3Aasync'%3B%0Aimport%20'dart%3Aisolate'%3B%0Aimport%20'dart%3Amirrors'%3B%0Aimport%20'package%3Aaqueduct%2Faqueduct.dart'%3B%0Aimport%20'package%3Adart_server%2Fdart_server.dart'%3B%0Aimport%20'package%3Aruntime%2Fruntime.dart'%3B%0AFuture%20main%20(List%3CString%3E%20args%2C%20Map%3CString%2C%20dynamic%3E%20message)%20async%20%7B%0A%20%20final%20sendPort%20%3D%20message%5B'_sendPort'%5D%3B%0A%20%20final%20executable%20%3D%20new%20GetChannelExecutable(message)%3B%0A%20%20final%20result%20%3D%20await%20executable.execute()%3B%0A%20%20sendPort.send(%7B%22_result%22%3A%20result%7D)%3B%0A%7D%0A%20%20%20%20%0Aclass%20GetChannelExecutable%20extends%20Executable%3CString%3E%20%7BGetChannelExecutable(Map%3CString%2C%20dynamic%3E%20message)%20%3A%20super(message)%3B%20%40override%20Future%3CString%3E%20execute()%20async%20%7Bfinal%20channels%20%3D%20RuntimeContext.current.runtimes.iterable.whereType%3CChannelRuntime%3E()%3B%20if%20(channels.length%20!%3D%201)%20%7Bthrow%20StateError(%22No%20ApplicationChannel%20subclass%20was%20found%20for%20this%20project.%20%22%20%22Make%20sure%20it%20is%20imported%20in%20your%20application%20library%20file.%22)%3B%7D%20var%20runtime%20%3D%20channels.first%3B%20if%20(runtime%20%3D%3D%20null)%20%7Breturn%20null%3B%7D%20return%20MirrorSystem.getName(reflectClass(runtime.channelType).simpleName)%3B%7D%20static%20List%3CString%3E%20importsForPackage(String%20packageName)%20%3D%3E%20%5B%22package%3Aaqueduct%2Faqueduct.dart%22%2C%20%22package%3A%24packageName%2F%24packageName.dart%22%2C%20%22package%3Aruntime%2Fruntime.dart%22%5D%3B%7D%0Aabstract%20class%20Executable%3CT%3E%20%7BExecutable(this.message)%20%3A%20_sendPort%20%3D%20message%5B%22_sendPort%22%5D%3B%20Future%3CT%3E%20execute()%3B%20final%20Map%3CString%2C%20dynamic%3E%20message%3B%20final%20SendPort%20_sendPort%3B%20U%20instanceOf%3CU%3E(String%20typeName%2C%20%7BList%20positionalArguments%3A%20const%20%5B%5D%2C%20Map%3CSymbol%2C%20dynamic%3E%20namedArguments%2C%20Symbol%20constructorName%7D)%20%7BClassMirror%20typeMirror%20%3D%20currentMirrorSystem().isolate.rootLibrary.declarations%5Bnew%20Symbol(typeName)%5D%3B%20if%20(typeMirror%20%3D%3D%20null)%20%7BtypeMirror%20%3D%20currentMirrorSystem().libraries.values.where((lib)%20%3D%3E%20lib.uri.scheme%20%3D%3D%20%22package%22%20%7C%7C%20lib.uri.scheme%20%3D%3D%20%22file%22).expand((lib)%20%3D%3E%20lib.declarations.values).firstWhere((decl)%20%3D%3E%20decl%20is%20ClassMirror%20%26%26%20MirrorSystem.getName(decl.simpleName)%20%3D%3D%20typeName%2C%20orElse%3A%20()%20%3D%3E%20throw%20new%20ArgumentError(%22Unknown%20type%20'%24typeName'.%20Did%20you%20forget%20to%20import%20it%3F%22))%3B%7D%20return%20typeMirror.newInstance(constructorName%20%3F%3F%20const%20Symbol(%22%22)%2C%20positionalArguments%2C%20namedArguments).reflectee%20as%20U%3B%7D%20void%20send(dynamic%20message)%20%7B_sendPort.send(message)%3B%7D%20void%20log(String%20message)%20%7B_sendPort.send(%7B%22_line_%22%20%3A%20message%7D)%3B%7D%7D%0A:14:483: Error: The value 'null' can't be returned from an async function with return type 'Future<String>' because 'Future<String>' is not nullable.
 - 'Future' is from 'dart:async'.
class GetChannelExecutable extends Executable<String> {GetChannelExecutable(Map<String, dynamic> message) : super(message); @override Future<String> execute() async {final channels = RuntimeContext.current.runtimes.iterable.whereType<ChannelRuntime>(); if (channels.length != 1) {throw StateError("No ApplicationChannel subclass was found for this project. " "Make sure it is imported in your application library file.");} var runtime = channels.first; if (runtime == null) {return null;} return MirrorSystem.getName(reflectClass(runtime.channelType).simpleName);} static List<String> importsForPackage(String packageName) => ["package:aqueduct/aqueduct.dart", "package:$packageName/$packageName.dart", "package:runtime/runtime.dart"];}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  ^
data:application/dart;charset=utf-8,import%20'dart%3Aasync'%3B%0Aimport%20'dart%3Aisolate'%3B%0Aimport%20'dart%3Amirrors'%3B%0Aimport%20'package%3Aaqueduct%2Faqueduct.dart'%3B%0Aimport%20'package%3Adart_server%2Fdart_server.dart'%3B%0Aimport%20'package%3Aruntime%2Fruntime.dart'%3B%0AFuture%20main%20(List%3CString%3E%20args%2C%20Map%3CString%2C%20dynamic%3E%20message)%20async%20%7B%0A%20%20final%20sendPort%20%3D%20message%5B'_sendPort'%5D%3B%0A%20%20final%20executable%20%3D%20new%20GetChannelExecutable(message)%3B%0A%20%20final%20result%20%3D%20await%20executable.execute()%3B%0A%20%20sendPort.send(%7B%22_result%22%3A%20result%7D)%3B%0A%7D%0A%20%20%20%20%0Aclass%20GetChannelExecutable%20extends%20Executable%3CString%3E%20%7BGetChannelExecutable(Map%3CString%2C%20dynamic%3E%20message)%20%3A%20super(message)%3B%20%40override%20Future%3CString%3E%20execute()%20async%20%7Bfinal%20channels%20%3D%20RuntimeContext.current.runtimes.iterable.whereType%3CChannelRuntime%3E()%3B%20if%20(channels.length%20!%3D%201)%20%7Bthrow%20StateError(%22No%20ApplicationChannel%20subclass%20was%20found%20for%20this%20project.%20%22%20%22Make%20sure%20it%20is%20imported%20in%20your%20application%20library%20file.%22)%3B%7D%20var%20runtime%20%3D%20channels.first%3B%20if%20(runtime%20%3D%3D%20null)%20%7Breturn%20null%3B%7D%20return%20MirrorSystem.getName(reflectClass(runtime.channelType).simpleName)%3B%7D%20static%20List%3CString%3E%20importsForPackage(String%20packageName)%20%3D%3E%20%5B%22package%3Aaqueduct%2Faqueduct.dart%22%2C%20%22package%3A%24packageName%2F%24packageName.dart%22%2C%20%22package%3Aruntime%2Fruntime.dart%22%5D%3B%7D%0Aabstract%20class%20Executable%3CT%3E%20%7BExecutable(this.message)%20%3A%20_sendPort%20%3D%20message%5B%22_sendPort%22%5D%3B%20Future%3CT%3E%20execute()%3B%20final%20Map%3CString%2C%20dynamic%3E%20message%3B%20final%20SendPort%20_sendPort%3B%20U%20instanceOf%3CU%3E(String%20typeName%2C%20%7BList%20positionalArguments%3A%20const%20%5B%5D%2C%20Map%3CSymbol%2C%20dynamic%3E%20namedArguments%2C%20Symbol%20constructorName%7D)%20%7BClassMirror%20typeMirror%20%3D%20currentMirrorSystem().isolate.rootLibrary.declarations%5Bnew%20Symbol(typeName)%5D%3B%20if%20(typeMirror%20%3D%3D%20null)%20%7BtypeMirror%20%3D%20currentMirrorSystem().libraries.values.where((lib)%20%3D%3E%20lib.uri.scheme%20%3D%3D%20%22package%22%20%7C%7C%20lib.uri.scheme%20%3D%3D%20%22file%22).expand((lib)%20%3D%3E%20lib.declarations.values).firstWhere((decl)%20%3D%3E%20decl%20is%20ClassMirror%20%26%26%20MirrorSystem.getName(decl.simpleName)%20%3D%3D%20typeName%2C%20orElse%3A%20()%20%3D%3E%20throw%20new%20ArgumentError(%22Unknown%20type%20'%24typeName'.%20Did%20you%20forget%20to%20import%20it%3F%22))%3B%7D%20return%20typeMirror.newInstance(constructorName%20%3F%3F%20const%20Symbol(%22%22)%2C%20positionalArguments%2C%20namedArguments).reflectee%20as%20U%3B%7D%20void%20send(dynamic%20message)%20%7B_sendPort.send(message)%3B%7D%20void%20log(String%20message)%20%7B_sendPort.send(%7B%22_line_%22%20%3A%20message%7D)%3B%7D%7D%0A:15:387: Error: A value of type 'DeclarationMirror?' can't be assigned to a variable of type 'ClassMirror'.
 - 'DeclarationMirror' is from 'dart:mirrors'.
 - 'ClassMirror' is from 'dart:mirrors'.
abstract class Executable<T> {Executable(this.message) : _sendPort = message["_sendPort"]; Future<T> execute(); final Map<String, dynamic> message; final SendPort _sendPort; U instanceOf<U>(String typeName, {List positionalArguments: const [], Map<Symbol, dynamic> namedArguments, Symbol constructorName}) {ClassMirror typeMirror = currentMirrorSystem().isolate.rootLibrary.declarations[new Symbol(typeName)]; if (typeMirror == null) {typeMirror = currentMirrorSystem().libraries.values.where((lib) => lib.uri.scheme == "package" || lib.uri.scheme == "file").expand((lib) => lib.declarations.values).firstWhere((decl) => decl is ClassMirror && MirrorSystem.getName(decl.simpleName) == typeName, orElse: () => throw new ArgumentError("Unknown type '$typeName'. Did you forget to import it?"));} return typeMirror.newInstance(constructorName ?? const Symbol(""), positionalArguments, namedArguments).reflectee as U;} void send(dynamic message) {_sendPort.send(message);} void log(String message) {_sendPort.send({"_line_" : message});}}
                                                                                                                                                                                                                                                                                                                                                                                                  ^
data:application/dart;charset=utf-8,import%20'dart%3Aasync'%3B%0Aimport%20'dart%3Aisolate'%3B%0Aimport%20'dart%3Amirrors'%3B%0Aimport%20'package%3Aaqueduct%2Faqueduct.dart'%3B%0Aimport%20'package%3Adart_server%2Fdart_server.dart'%3B%0Aimport%20'package%3Aruntime%2Fruntime.dart'%3B%0AFuture%20main%20(List%3CString%3E%20args%2C%20Map%3CString%2C%20dynamic%3E%20message)%20async%20%7B%0A%20%20final%20sendPort%20%3D%20message%5B'_sendPort'%5D%3B%0A%20%20final%20executable%20%3D%20new%20GetChannelExecutable(message)%3B%0A%20%20final%20result%20%3D%20await%20executable.execute()%3B%0A%20%20sendPort.send(%7B%22_result%22%3A%20result%7D)%3B%0A%7D%0A%20%20%20%20%0Aclass%20GetChannelExecutable%20extends%20Executable%3CString%3E%20%7BGetChannelExecutable(Map%3CString%2C%20dynamic%3E%20message)%20%3A%20super(message)%3B%20%40override%20Future%3CString%3E%20execute()%20async%20%7Bfinal%20channels%20%3D%20RuntimeContext.current.runtimes.iterable.whereType%3CChannelRuntime%3E()%3B%20if%20(channels.length%20!%3D%201)%20%7Bthrow%20StateError(%22No%20ApplicationChannel%20subclass%20was%20found%20for%20this%20project.%20%22%20%22Make%20sure%20it%20is%20imported%20in%20your%20application%20library%20file.%22)%3B%7D%20var%20runtime%20%3D%20channels.first%3B%20if%20(runtime%20%3D%3D%20null)%20%7Breturn%20null%3B%7D%20return%20MirrorSystem.getName(reflectClass(runtime.channelType).simpleName)%3B%7D%20static%20List%3CString%3E%20importsForPackage(String%20packageName)%20%3D%3E%20%5B%22package%3Aaqueduct%2Faqueduct.dart%22%2C%20%22package%3A%24packageName%2F%24packageName.dart%22%2C%20%22package%3Aruntime%2Fruntime.dart%22%5D%3B%7D%0Aabstract%20class%20Executable%3CT%3E%20%7BExecutable(this.message)%20%3A%20_sendPort%20%3D%20message%5B%22_sendPort%22%5D%3B%20Future%3CT%3E%20execute()%3B%20final%20Map%3CString%2C%20dynamic%3E%20message%3B%20final%20SendPort%20_sendPort%3B%20U%20instanceOf%3CU%3E(String%20typeName%2C%20%7BList%20positionalArguments%3A%20const%20%5B%5D%2C%20Map%3CSymbol%2C%20dynamic%3E%20namedArguments%2C%20Symbol%20constructorName%7D)%20%7BClassMirror%20typeMirror%20%3D%20currentMirrorSystem().isolate.rootLibrary.declarations%5Bnew%20Symbol(typeName)%5D%3B%20if%20(typeMirror%20%3D%3D%20null)%20%7BtypeMirror%20%3D%20currentMirrorSystem().libraries.values.where((lib)%20%3D%3E%20lib.uri.scheme%20%3D%3D%20%22package%22%20%7C%7C%20lib.uri.scheme%20%3D%3D%20%22file%22).expand((lib)%20%3D%3E%20lib.declarations.values).firstWhere((decl)%20%3D%3E%20decl%20is%20ClassMirror%20%26%26%20MirrorSystem.getName(decl.simpleName)%20%3D%3D%20typeName%2C%20orElse%3A%20()%20%3D%3E%20throw%20new%20ArgumentError(%22Unknown%20type%20'%24typeName'.%20Did%20you%20forget%20to%20import%20it%3F%22))%3B%7D%20return%20typeMirror.newInstance(constructorName%20%3F%3F%20const%20Symbol(%22%22)%2C%20positionalArguments%2C%20namedArguments).reflectee%20as%20U%3B%7D%20void%20send(dynamic%20message)%20%7B_sendPort.send(message)%3B%7D%20void%20log(String%20message)%20%7B_sendPort.send(%7B%22_line_%22%20%3A%20message%7D)%3B%7D%7D%0A:15:601: Error: A value of type 'DeclarationMirror' can't be assigned to a variable of type 'ClassMirror'.
 - 'DeclarationMirror' is from 'dart:mirrors'.
 - 'ClassMirror' is from 'dart:mirrors'.
abstract class Executable<T> {Executable(this.message) : _sendPort = message["_sendPort"]; Future<T> execute(); final Map<String, dynamic> message; final SendPort _sendPort; U instanceOf<U>(String typeName, {List positionalArguments: const [], Map<Symbol, dynamic> namedArguments, Symbol constructorName}) {ClassMirror typeMirror = currentMirrorSystem().isolate.rootLibrary.declarations[new Symbol(typeName)]; if (typeMirror == null) {typeMirror = currentMirrorSystem().libraries.values.where((lib) => lib.uri.scheme == "package" || lib.uri.scheme == "file").expand((lib) => lib.declarations.values).firstWhere((decl) => decl is ClassMirror && MirrorSystem.getName(decl.simpleName) == typeName, orElse: () => throw new ArgumentError("Unknown type '$typeName'. Did you forget to import it?"));} return typeMirror.newInstance(constructorName ?? const Symbol(""), positionalArguments, namedArguments).reflectee as U;} void send(dynamic message) {_sendPort.send(message);} void log(String message) {_sendPort.send({"_line_" : message});}}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        ^
  **** Stacktrace
  ****
PS D:\projects\spur\backend>`

I assume it has to do with the dart SDK being on the latest and running in sound null safety,

So I downloaded dart2.8.4 SDK and updated the path variable. but dart --version still shows 2.12.

C:\Users\RR>where dart
C:\src\flutter\bin\dart
C:\src\flutter\bin\dart.bat
C:\src\dart\sdk-2.8.4\sdk\bin\dart
C:\src\dart\sdk-2.8.4\sdk\bin\dart.bat

Can someone describe (for a newbie) how I can work around this? Preferably using latest dart for my flutter project and then downgrade it for aqueduct project?

stablekernel / aqueduct

Another newb with null sound problems #934