There are no logs in cli application

[sc0rp10]

Hi! I try to create console application on Dart and logs is very important for this application, but, unfortunately, I can't see any log messages in the console even with very simple code from the example:

I created a new empty project

$ dart create . --force
Creating testlogger using template console...

  .gitignore
  analysis_options.yaml
  CHANGELOG.md
  pubspec.yaml
  README.md
  bin/testlogger.dart
  lib/testlogger.dart
  test/testlogger_test.dart

Running pub get...                     1.1s
  Resolving dependencies...
  Changed 47 dependencies!
  4 packages have newer versions incompatible with dependency constraints.
  Try `dart pub outdated` for more information.

Created project testlogger in .! In order to get started, run the following commands:

  cd .
  dart run

Then I added the Logger library:

$ dart pub add logger
Resolving dependencies...
  lints 2.1.1 (3.0.0 available)
+ logger 2.2.0
  vm_service 14.0.0 (14.2.1 available)
  web 0.4.2 (0.5.1 available)
  web_socket_channel 2.4.3 (2.4.5 available)
Changed 1 dependency!
4 packages have newer versions incompatible with dependency constraints.
Try `dart pub outdated` for more information.

I wrote dead simply script based on examples:

$ cat bin/testlogger.dart
import 'package:logger/logger.dart';

void main(List<String> arguments) {
    var logger = Logger();

    logger.w("Logger is working!");

    print("any output");
}

Finally I run the script:

$ dart bin/testlogger.dart
any output

But, unfortunately, I didn't see any logs in my console. I tried many different options - filters, outputs, levels but there is still no luck.

What can be wrong?

[sc0rp10]

I dig into the code and found problematic string:

https://github.com/SourceHorizon/logger/blob/main/lib/src/filters/development_filter.dart#L12

var shouldLog = false;
assert(() {
  if (event.level.value >= level!.value) {
    shouldLog = true;
  }
  return true;
}());

Asserts have to be enabled to allow logger print logs. It's better to add this information to the readme at least, but IMO the logger shouldn't rely on asserts.

[Bungeefan]

Hi, this is already noted in the README, as well as in the documentation of the default filter: https://github.com/SourceHorizon/logger?tab=readme-ov-file#logfilter

The LogFilter decides which log events should be shown and which don't.
The default implementation (DevelopmentFilter) shows all logs with level >= Logger.level while in debug mode (i.e., running dart with --enable-asserts). In release mode all logs are omitted.

You are free to use the ProductionFilter which doesn't rely on asserts (i.e. debug mode).