[Formatting issue] Enums that have parameters get their semicolon moved to the next line when `trailing_commas: preserve`, affects Flutter 3.38.0

[josxha]

What input code did you provide to the formatter?

enum Test2 {
  x('example'),
  y('example2'),
  z('example3');

  const Test2(this.someVariable);

  final String someVariable;
}

What output did the formatter produce?

enum Test2 {
  x('example'),
  y('example2'),
  z('example3')
  ;

  const Test2(this.someVariable);

  final String someVariable;
}

What output did you expect or want the formatter to produce?

The formatter shouldn't move the semicolon into a new line.

enum Test2 {
  x('example'),
  y('example2'),
  z('example3');

  const Test2(this.someVariable);

  final String someVariable;
}

Anything else we should know?

I just upgraded to Flutter 3.38.0 (using Dart 3.10.0-290.4.beta) and noticed that dart format results in some strange formatting results for enums that use parameters. Enums without parameters are unaffected.

Use the following content in analysis_options.yaml:

formatter:
  trailing_commas: preserve

I created a minimum reproducable example in https://github.com/josxha/dart_format_test
The bug gets reproduced in this commit: josxha/dart_format_test@e0a8f0d

I was able to reproduce this issue in the following versions of Dart:

• Dart 3.10.0-290.4.beta on Windows 11 amd64, used in the stable Flutter 3.38.0 release
• Dart 3.11.0-93.1.beta using docker run --rm -it -v ${PWD}:/test dart:3.11.0-93.1.beta dart format /test

[parlough]

I hit this too, thanks for reporting it.

Personally I'd say I'm fine with the semicolon moving to the next line if a comma is always added after the final enum value to make adding new values easier.

[jkoenig134]

As an addition - the same thing happens with enums that don't have parameters, but have methods:

before

enum Test {
  x,
  y,
  z;

  String get upper => name.toUpperCase();
}

after

enum Test {
  x,
  y,
  z
  ;

  String get upper => name.toUpperCase();
}

[alexobviously]

Any update or workaround for this? It soft blocks our adoption of flutter 3.38