prefer_prefixed_global_constants

v1.0.0WarningConfigurableClass Naming

Flags a public top-level constant that does not carry the prefix you configure.

A top-level constant is in scope everywhere the library is imported, under a name that competes with every local. defaultTimeout at the top level reads identically to a local of the same name at the point of use, so a prefix — kDefaultTimeout, Flutter’s own convention — makes the origin visible without a jump to the declaration.

This rule is in no preset and reports nothing until you set prefix:. Every example below shows the configuration that produces it.

many_lints:
  rules:
    prefer_prefixed_global_constants:
      prefix: k

rules:
  prefer_prefixed_global_constants:
    prefix: k

Don’t

With prefix: k:

const defaultTimeout = Duration(seconds: 30);  // LINT
const maxRetries = 3;                          // LINT
const serviceHost = 'example.com';             // LINT

Do

const kDefaultTimeout = Duration(seconds: 30);
const kMaxRetries = 3;
const kServiceHost = 'example.com';

Examples

Every declaration in one statement is checked

rules:
  prefer_prefixed_global_constants:
    prefix: k

// Don't — two constants, two diagnostics
const minPort = 1024, maxPort = 65535;

// Do
const kMinPort = 1024, kMaxPort = 65535;

Private constants and non-constants are left alone

// Not reported — private, so it cannot collide outside this library
const _retryBackoff = Duration(milliseconds: 200);

// Not reported — `final`, not `const`
final sessionId = generateId();

// Reported
const timeout = Duration(seconds: 5);   // LINT

A different house prefix

The prefix is a plain string, so a project with its own vocabulary spells it out:

rules:
  prefer_prefixed_global_constants:
    prefix: app

// Don't
const primaryColorHex = 0xFF0468D7;   // LINT

// Do
const appPrimaryColorHex = 0xFF0468D7;

Scope it to one layer

Design tokens may want the prefix while generated code does not:

rules:
  prefer_prefixed_global_constants:
    prefix: k
    exclude: ['lib/**/*.g.dart', 'lib/**/*.freezed.dart']

Options

Option	Type	Default	Description
`prefix`	string	`—`	The required prefix. Unset means the rule is silent

Known limitations

Constants only. A top-level final or var is not reported, even though it shares the same scope problem. Only const declarations are checked.

Case is not enforced. The check is a plain startsWith, so ktimeout satisfies prefix: k as readily as kTimeout does. Pair this with prefer_correct_type_name and the SDK’s constant_identifier_names if casing matters.

Turning this rule off

To disable this rule:

rules:
  prefer_prefixed_global_constants: false

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

avoid_unnecessary_enum_prefix — Drop an enum name repeated in its own constants.
match_class_name_pattern — Match class names against a regular expression.
prefer_boolean_prefixes — Name booleans as questions.
prefer_correct_callback_field_name — Name callbacks onSomething, the way Flutter does.