Linter tool support for embedded SDKs.

[yyoon]

In our Flutter code, we use some classes / enums in dart:ui extended by sky_engine.
Linter seems to think these classes are undefined, which is not the case.

Steps to reproduce:

• Create a new flutter project using flutter create
• In the created lib/main.dart, Modify the text widget in the sample code to use FontWeight.bold style, which is defined in dart:ui.

child: new Text(
  'Button tapped $_counter time${ _counter == 1 ? '' : 's' }.',
  style: new TextStyle(fontWeight: FontWeight.bold),
),

• This code runs fine and dartanalyzer doesn't show any errors, but running pub global linter . gives the following warning:

<omitted>/foo/lib/main.dart 33:46 [static warning] Undefined name 'FontWeight'
            style: new TextStyle(fontWeight: FontWeight.bold),
                                             ^^^^^^^^^^
<omitted>/foo/lib/main.dart 10:7 [lint] Document all public members
class FlutterDemo extends StatefulWidget {
      ^^^^^^^^^^^
<omitted>/foo/lib/main.dart 11:3 [lint] Document all public members
  FlutterDemo({Key key}) : super(key: key);
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

2 files analyzed, 3 issues found, in 5220 ms.

The last two are valid lint issues, but the first one is false positive.

@dvdwasibi @sethladd

[bwilkerson]

Perhaps the linter hasn't been updated to understand embedder files. Note that dartanalyzer will also produce lints when passed the --lints flag, so that might be a work-around until we can fix the problem.

[yyoon]

Does the --lints flag do the exact same thing as linter? I tried it just now and it doesn't seem to give me the "Document all public memebers" issue.

[bwilkerson]

It is suppose to. I'm not sure why they're different.

Does dartanalyzer report other lints enabled in the analysis options file?

[yyoon]

I see. We didn't have the .analysis_options file in the project. I'll add it and use dartanalyzer for now.

[pq]

Perhaps the linter hasn't been updated to understand embedder files.

👍 This is right.

@yyoon : is dartanalyzer working for you? Alternatively, flutter analyze should also do the trick?

[yyoon]

@pq dartanalyzer is working fine for now, but it doesn't display the issues as nice as linter does. We would probably want to go back to linter when this issue is fixed.

BTW, why are there these two separate tools in the first place, when dartanalyzer can just do the trick? Are they expected to be used in different situations?

[sethladd]

cc @kevmoo

[pq]

BTW, why are there these two separate tools in the first place, when dartanalyzer can just do the trick? Are they expected to be used in different situations?

The linter command line was created when we were bootstrapping the linter project and did not have a plugin story for the analyzer yet. It's also quite handy for testing lints. The preferred way, moving forward, would be to use dartanalyzer. For convenience, I'd like to update the linter binary as well to essentially just forward to the analyzer.

Having said that, I did add some display tweaks that you may miss. What specifically would you like to see continue? Maybe we can upstream those bits to dartanalyzer...

[yyoon]

The linter shows the actual line of code and highlights the exact part of the line that the issue is referring to:

foo/lib/main.dart 10:7 [lint] Document all public members
class FlutterDemo extends StatefulWidget {
      ^^^^^^^^^^^

whereas dartanalyzer --lints only shows the file name and the line number:

[lint] Document all public members (/Users/youngseokyoon/Programming/baku/modules/email/lib/main.dart, line 20, col 7)

It'd be nice to have the same display format in dartanalyzer.

[pq]

Thanks! Feel free to open a feature request on the analyzer.

cc @bwilkerson

[yyoon]

Just created on issue there. Thanks!