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Many Lints

avoid_commented_out_code

v0.3.0WarningFixConfigurableCode Quality

Flags comments that look like commented-out Dart code rather than descriptive text. This includes commented-out function definitions, variable declarations, import statements, and other recognizable code patterns. The quick fix removes the flagged comment block.

Why use this rule

Section titled “Why use this rule”

Commented-out code is technical debt that clutters the codebase and confuses readers about what is intentional. Version control already preserves old code, making commented-out blocks unnecessary. Removing them keeps the codebase clean and reduces cognitive load during code review.

See also: Effective Dart: Documentation

Don’t

Section titled “Don’t”
class BadExamples {
  // void apply(String value) {
  //   print(value);
  // }


  // final x = 42;


  // import 'dart:async';


  void another() {}
}

Do

Section titled “Do”
class GoodExamples {
  // This method handles the main processing logic
  // and delegates to the appropriate handler


  // Temporarily disabled, enable in 1.0
  void another() {}
}

Known limitations

Section titled “Known limitations”

Detection is a heuristic over each block of comments: a block is reported when at least half its non-empty lines look like Dart rather than prose. Blocks are formed from comments on directly consecutive lines — a blank line ends one, and so does any code between them. A comment trailing code (foo(); // note) is its own block, since it annotates the line beside it.

That means a single commented-out line surrounded by explanatory prose may not reach the ratio, and prose that reads like code (// returns null;) can be reported. Suppress those with // ignore: many_lints/avoid_commented_out_code.

Turning this rule off

Section titled “Turning this rule off”

This rule is in the opinionated preset, so it is on with preset: opinionated, or by name:

many_lints.yaml
rules:
  avoid_commented_out_code: true

To turn it off again:

many_lints.yaml
rules:
  avoid_commented_out_code: false

To keep the rule on but skip certain paths, use per-rule exclude.

Options

Section titled “Options”
analysis_options.yaml
many_lints:
  rules:
    avoid_commented_out_code:
      min_lines: 2
Option Type Default Description
min_lines int 1 Minimum number of consecutive commented-out lines before a block is reported
Section titled “Related rules”