Formatter problem with initializer list

[DartBot]

<img src="https://avatars.githubusercontent.com/u/648527?v=3" align="left" width="96" height="96"hspace="10"> Issue by Fox32
Originally opened as dart-lang/sdk#17514

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Dart formatter is unable to format this code correctly:

  Vector3(double x_, double y_, double z_): storage = new Float32List(3) {
    setValues(x_, y_, z_);
  }

If I give a hint by adding a line break before the ":", everything works fine. If I add a space instead, the space is removed.

Dart Editor version 1.3.0.dev_03_02 (DEV)
Dart SDK version 1.3.0-dev.3.2

[DartBot]

<img src="https://avatars.githubusercontent.com/u/17034?v=3" align="left" width="48" height="48"hspace="10"> Comment by kevmoo

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Added Area-Formatter, Triaged labels.

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<img src="https://avatars.githubusercontent.com/u/8616782?v=3" align="left" width="48" height="48"hspace="10"> Comment by clayberg

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Set owner to @pq.
Added this to the 1.3 milestone.
Removed Priority-Unassigned label.
Added Priority-Medium label.

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<img src="https://avatars.githubusercontent.com/u/67586?v=3" align="left" width="48" height="48"hspace="10"> Comment by pq

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Removed this from the 1.3 milestone.
Added this to the 1.4 milestone.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/67586?v=3" align="left" width="48" height="48"hspace="10"> Comment by pq

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Thanks for the report. I just landed a related fix that might address this (https://codereview.chromium.org/231743002/). The current behavior formats this:

class Vector3 {
  var storage;
  Vector3(double x_, double y_, double z_): storage = new Float32List(3) {
    setValues(x_, y_, z_);
  }
}

to:

class Vector3 {
  var storage;
  Vector3(double x_, double y_, double z_) : storage = new Float32List(3) {
    setValues(x_, y_, z_);
  }
}

If you're still seeing surprising results after dart-lang/sdk@3edb0ef, please re-open this bug and include the expected output.

Again thanks for the feedback!

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Added AssumedStale label.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/648527?v=3" align="left" width="48" height="48"hspace="10"> Comment by Fox32

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Maybe the formatting rule should be more specific in the Dart Style Guide as I assumed that it is required to always do a new line before the ':'.

https://www.dartlang.org/articles/style-guide/#do-format-constructor-initialization-lists-with-each-field-on-its-own-line

[DartBot]

<img src="https://avatars.githubusercontent.com/u/67586?v=3" align="left" width="48" height="48"hspace="10"> Comment by pq

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Ah, wait. Good catch. I think we agreed that a single initializer could live on a single line but now I'm not sure. Anyway, either this or the style guide need updating. :)

Bob, Siggi: thoughts?

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cc @sigmundch.
Set owner to @munificent.
Added Triaged label.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2049220?v=3" align="left" width="48" height="48"hspace="10"> Comment by sigmundch

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Yes - inline initializers are allowed, and are not necessarily limited to just one. Only when you exceed the 80 column limit we need to break on the ":".

I believe all of these are valid (correctly formatted) as is:

class Classname {
  int a;
  int b;
  int c;

  Classname.one() : a = 1, b = 2, c = 3;

  Classname.two() : a = 1, b = 2, c = 3 {
    ...
  }

  Classname.three()
    : a = 1, b = 2, c = 3 {
    ...
  }

  Classname.three()
    : a = 1,
      b = 2,
      c = 3 {
    ...
  }

[DartBot]

<img src="https://avatars.githubusercontent.com/u/46275?v=3" align="left" width="48" height="48"hspace="10"> Comment by munificent

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+1 what Siggy said (though personally I always wrap them). One nit: the ":" should be indented +4, like:

  Classname.three()
      : a = 1, b = 2, c = 3 {
    ...
  }

[DartBot]

<img src="https://avatars.githubusercontent.com/u/648527?v=3" align="left" width="48" height="48"hspace="10"> Comment by Fox32

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Then the guide should be updated, as it states: "DO format constructor initialization lists with each field on its own line."

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2156198?v=3" align="left" width="48" height="48"hspace="10"> Comment by kasperl

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Removed this from the 1.4 milestone.
Added this to the 1.5 milestone.

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<img src="https://avatars.githubusercontent.com/u/2156198?v=3" align="left" width="48" height="48"hspace="10"> Comment by kasperl

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Removed this from the 1.5 milestone.
Added this to the 1.6 milestone.

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<img src="https://avatars.githubusercontent.com/u/2156198?v=3" align="left" width="48" height="48"hspace="10"> Comment by kasperl

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Removed this from the 1.6 milestone.
Added Oldschool-Milestone-1.6 label.

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<img src="https://avatars.githubusercontent.com/u/2156198?v=3" align="left" width="48" height="48"hspace="10"> Comment by kasperl

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Removed Oldschool-Milestone-1.6 label.

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<img src="https://avatars.githubusercontent.com/u/46275?v=3" align="left" width="48" height="48"hspace="10"> Comment by munificent

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Added AssumedStale label.