markup_analyzer 4.0.0

This tool checks the markup of a Flutter project and generates a report.

MarkupAnalyzer Lint Rule

Description

Markup Analyzer is a native Dart analyzer plugin that enforces localization in Flutter widgets. It flags raw string expressions passed to widget constructors, encouraging the use of localized strings instead.

The plugin uses the built-in analysis_server_plugin — no additional tools required.

• Installation
• Configuration
• Diagnostics
• Examples

Installation

Add the plugin to your analysis_options.yaml. No changes to pubspec.yaml required:

plugins:
  markup_analyzer:
    diagnostics:
      simple_string: error
      string_interpolation: error
      binary_expression: warning
      adjacent_strings: warning
      method_invocation: warning
      simple_identifier: none
      prefixed_identifier: none
      function_invocation: none

Configuration

Each diagnostic can be set to error, warning, info, or none (disabled):

Code	Default
simple_string	error
string_interpolation	error
binary_expression	warning
adjacent_strings	warning
method_invocation	warning
simple_identifier	none
prefixed_identifier	none
function_invocation	none

Diagnostics

Code	Description
simple_string	Simple string literal passed to a widget
string_interpolation	String interpolation passed to a widget
adjacent_strings	Adjacent string literals passed to a widget
binary_expression	Binary string expression (e.g. 'a' + 'b') passed to a widget
prefixed_identifier	Prefixed identifier of type String (e.g. widget.title) passed to a widget
method_invocation	Method call returning String (e.g. 'x'.tr()) passed to a widget
simple_identifier	Variable of type String passed to a widget
function_invocation	Function expression returning String passed to a widget

All checks are widget-scoped: only constructor calls of classes that extend Widget are analyzed.

Examples

Simple string literal

// BAD
Text('Hello, world!');

// GOOD
Text(AppLocalizations.of(context).greeting);

String interpolation

// BAD
Text('Hello, $name!');

// GOOD
Text(AppLocalizations.of(context).helloWithName(name));

Adjacent strings

// BAD
Text(
  'Hello, '
  'world!',
);

Binary expression

// BAD
Text('Hello, ' + 'world!');

Prefixed identifier

// BAD
Text(widget.title);

Method invocation

// BAD
Text('hello'.tr());

// GOOD
Text(AppLocalizations.of(context).hello);

Simple identifier

// BAD
final String title = 'Hello';
Text(title);

Function invocation

// BAD
Text((() => 'Hello')());