avoid_banned_exports

v1.0.0WarningConfigurableArchitecture

Flags export directives for libraries you ban, optionally only inside the directories you name. Barrel-file hygiene: it keeps internal libraries out of a package’s public API.

This rule reports nothing until you configure it.

Why use this rule

A barrel file decides what a package promises. An export added there for convenience — to save one import in a test, say — silently makes everything in that library public, and removing it later is a breaking change for every consumer.

This is kept separate from avoid_banned_imports on purpose: depending on a library internally and re-exporting it to consumers are different decisions. A package is often perfectly free to use something it must not expose.

See also: Effective Dart: libraries, Dart package layout conventions

Don’t

// in lib/my_package.dart
//
// With an entry banning 'src/internal/.*' in lib/*.dart:
export 'src/internal/cache.dart';  // LINT: makes the cache public API

Do

// in lib/my_package.dart
//
// Export only what consumers are meant to depend on.
export 'src/api/client.dart';
export 'src/api/models.dart';

Turning this rule off

This rule is in no preset, so it is off unless you enable it by name:

many_lints.yaml

rules:
  avoid_banned_exports: true

To turn it off again:

many_lints.yaml

rules:
  avoid_banned_exports: false

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

Options

analysis_options.yaml

analysis_options.yaml

many_lints:
  rules:
    avoid_banned_exports:
      banned:
        - deny_pattern: ['src/internal/.*']
          in: ['lib/*.dart']
          message: 'Internal libraries must not be part of the public API.'

many_lints.yaml

many_lints.yaml

rules:
  avoid_banned_exports:
    banned:
      - deny_pattern: ['src/internal/.*']
        in: ['lib/*.dart']
        message: 'Internal libraries must not be part of the public API.'

Option	Type	Default	Description
banned	list of maps	[]	The entries to enforce. With none, the rule reports nothing

Each entry accepts:

Key	Type	Required	Description
deny	string or list	one of deny / deny_pattern	Export URIs banned by exact match
deny_pattern	string or list	one of deny / deny_pattern	Regular expressions, anchored to the whole URI
in	list of globs	no	Paths, relative to the package root, where the entry applies. Omit to apply everywhere
message	string	no	A project-specific explanation appended to the diagnostic

The URI is matched as written in the export directive, so a relative export is matched as the relative path you typed.

Scoping with in: ['lib/*.dart'] is the useful default here: a single * matches only top-level barrel files, leaving everything under lib/src/** free to export internally.

Related rules

• avoid_banned_annotations — Ban specific annotations, optionally scoped by directory.
• avoid_banned_imports — Ban imports of specific libraries, optionally scoped by directory.
• avoid_banned_names — Ban specific identifiers from being used as declaration names.
• avoid_banned_types — Ban specific types from being named, optionally scoped by directory.