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Many Lints

avoid_negated_conditions

v1.0.0WarningFixConfigurableControl Flow

This rule flags an if/else or a conditional expression whose condition is negated, so the else branch is the positive case.

Why use this rule

Section titled “Why use this rule”

When the condition is negated and there is an else, the reader has to hold a negation just to know what the second branch is for. Swapping the branches lets each one state its case directly.

The rule only fires where the swap is a genuine improvement:

  • Only with an else. A bare if (!x) return; is a guard, the clearest form there is — and prefer_early_return actively asks for it, so reporting it here would set the two rules fighting.
  • Never on an else if chain. That encodes an ordered sequence of tests; swapping the first pair would reorder the whole chain.
  • Never on != null or != 0. x != null is the null check the language is built around, and byPoints != 0 ? byPoints : ... is the comparator tie-break idiom. Both state a positive fact, and both turned up as false positives on a production codebase.
  • Never for a pattern if. The swapped branch could not see the bound variables.

This rule is in the pedantic preset: branch ordering is a house style.

Don’t

Section titled “Don’t”
if (!user.isActive) {
  showInactiveBanner();
} else {
  showDashboard();
}


final label = !isReady ? 'Waiting' : 'Ready';

Do

Section titled “Do”
if (user.isActive) {
  showDashboard();
} else {
  showInactiveBanner();
}


final label = isReady ? 'Ready' : 'Waiting';
// Still fine: a guard has no else to swap with.
if (!user.isActive) return;


// Still fine: `!= null` states a positive fact.
if (token != null) {
  use(token);
} else {
  requestToken();
}

Enabling this rule

Section titled “Enabling this rule”

This rule is in the pedantic preset, so it is enabled by preset: pedantic or by name:

many_lints.yaml
rules:
  avoid_negated_conditions:
    enabled: true

Options

Section titled “Options”
analysis_options.yaml
many_lints:
  rules:
    avoid_negated_conditions:
      report_not_equal: false
Option Type Default Description
report_not_equal bool true Whether != counts as a negation. != null and != 0 are never reported either way

Turning this rule off

Section titled “Turning this rule off”

To disable this rule:

many_lints.yaml
rules:
  avoid_negated_conditions: false

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

Section titled “Related rules”