feat: add static code diagnostic prefer-static-class

[roman-petrov]

Suggests to use static class member instead of global constants, variables and functions.

Pros:

• Easy to search: great help from IDE autocomplete. Type class/file name to find domain, and type dot to list all members.
• Easy to import: name conflicts will happen less often since all names are scoped to file name/class name. No need to use import 'file.dart' as 'file' to resolve name conflicts.
• Easy to read: declarations in code will be always shown paired with domain they belong to. Compare Circle.getArea and getArea or getCircleArea.
• member-ordering rule will be applied to class members.

Cons:

• The code amount might somehow increase.

When fixing rule issues and moving global members into a class, consider also renaming to avoid duplicating context.
For example, getCircleArea global function should become Circle.getArea, not Circle.getCircleArea.

For this rule it's recommended to exclude the test folder.

Use ignore-private configuration to ignore private global declarations.

Use ignore-names to ignore names matching regular expressions (for example, Riverpod providers, flutter hooks, etc).

Use ignore-annotations configuration to override default ignored annotation list.

⚙️ Config example {#config-example}

dart_code_metrics:
  ...
  rules:
    ...
    - prefer-static-class
        ignore-annotations:
          - allowedAnnotation
        ignore-private: true
        ignore-names:
          - (.*)Provider
          - use(.*)

Example {#example}

❌ Bad:

// circle.dart
int getCircleArea() {} // LINT
int getPerimeter() // LINT

const _PI = 3.14; // LINT

✅ Good:

// circle.dart
class Circle {
    static int getArea() {}
    static int getPerimeter() {}

    static const _PI = 3.14;
}

[codecov]

Codecov Report

Merging #1086 (f4de0ef) into master (37902ea) will increase coverage by 0.04%.
The diff coverage is 91.07%.

❗ Current head f4de0ef differs from pull request most recent head c57cc88. Consider uploading reports for the commit c57cc88 to get more accurate results

@@            Coverage Diff             @@
##           master    #1086      +/-   ##
==========================================
+ Coverage   84.85%   84.89%   +0.04%     
==========================================
  Files         330      333       +3     
  Lines        7275     7331      +56     
==========================================
+ Hits         6173     6224      +51     
- Misses       1102     1107       +5     

Impacted Files	Coverage Δ
...c/analyzers/lint_analyzer/rules/rules_factory.dart	75.00% <ø> (ø)
...eturning_widgets/avoid_returning_widgets_rule.dart	77.27% <ø> (ø)
...es_list/avoid_returning_widgets/config_parser.dart	100.00% <ø> (ø)
.../prefer_static_class/prefer_static_class_rule.dart	78.26% <78.26%> (ø)
.../rules_list/prefer_static_class/config_parser.dart	100.00% <100.00%> (ø)
.../rules/rules_list/prefer_static_class/visitor.dart	100.00% <100.00%> (ø)

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[roman-petrov]

I just have finished rule implementation. I also tested this rule on our code base and not found any false positives. I got ~90 true positives which we really should fix. @dkrutskikh , @incendial - can you please take a look?

[incendial]

Overall looks amazing! 🔥 Left a few small comments

[incendial]

Please use verifyNoIssues instead.

[incendial]

Same for NoIssues

[incendial]

And here

[incendial]

And here 🙂

[incendial]

I believe isEnitrypoint helper function should be used here. It covers not only main, but also other possible entry points.

[incendial]

Please use Identifier.isPrivateName instead of name.startsWith('_')

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication