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Many Lints

match_getter_setter_field_names

v1.0.0WarningCode Quality

This rule flags a getter and setter pair that does not read and write the same backing field.

This is the copy-paste bug that type checking cannot catch: both members compile, both have the right signature, and the mismatch only shows up as a value that will not stick. It is most common where a class has several similar pairs, which is exactly where it is hardest to spot by reading.

This rule is in the recommended preset.

Don’t

Section titled “Don’t”

A settings object with four near-identical pairs — the third one was pasted and half-edited:

class LayoutSettings {
  double _paddingTop = 0;
  double _paddingBottom = 0;
  double _marginTop = 0;
  double _marginBottom = 0;


  double get paddingTop => _paddingTop;
  set paddingTop(double value) => _paddingTop = value;


  double get paddingBottom => _paddingBottom;
  set paddingBottom(double value) => _paddingBottom = value;


  double get marginTop => _marginTop;
  set marginTop(double value) => _marginBottom = value; // writes the wrong field


  double get marginBottom => _marginBottom;
  set marginBottom(double value) => _marginBottom = value;
}

Do

Section titled “Do”
class LayoutSettings {
  double _marginTop = 0;
  double _marginBottom = 0;


  double get marginTop => _marginTop;
  set marginTop(double value) => _marginTop = value;


  double get marginBottom => _marginBottom;
  set marginBottom(double value) => _marginBottom = value;
}

The rule reads pairs in classes, mixins and extension types alike.

Known limitations

Section titled “Known limitations”

Only a pair whose bodies are a single field reference is compared, so several deliberate shapes are skipped rather than guessed at:

class Temperature {
  double _celsius = 0;
  double _fahrenheit = 0;


  // Skipped: the getter computes, so there is no single field to compare.
  double get celsius => (_fahrenheit - 32) / 1.8;
  set celsius(double value) => _fahrenheit = value * 1.8 + 32;


  // Skipped: the setter runs more than one statement.
  double get fahrenheit => _fahrenheit;
  set fahrenheit(double value) {
    assert(value > -459.67);
    _fahrenheit = value;
  }
}

A compound assignment (+=, ??=) reads the field too, so its asymmetry with the getter can be deliberate and is skipped as well. A getter with no matching setter, or the reverse, is never reported — there is nothing to compare it against.

Configuration

Section titled “Configuration”

This rule is on with preset: recommended or preset: opinionated.

Turning this rule off

Section titled “Turning this rule off”

To disable this rule:

many_lints.yaml
rules:
  match_getter_setter_field_names: false

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

Section titled “Related rules”