max_imports

v1.0.0WarningConfigurableCode Quality

This rule flags a file that imports more libraries than the configured budget.

Why use this rule

The import count measures how much a file depends on. A file importing twenty libraries is coupled to twenty things that can change under it, and usually has taken on more than one job.

This rule is in the pedantic preset.

Don’t

With max_imports: 5, a screen file that grew into a service layer:

import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:math';
import 'dart:typed_data';
import 'dart:developer'; // LINT: 6 imports, over the limit of 5

class ReportScreen {}

The diagnostic lands on the first directive, so it points at the import block rather than at whichever import happened to push it over.

Do

Split the file so each part imports only what it needs:

report_screen.dart

import 'dart:async';
import 'dart:convert';

class ReportScreen {}

report_encoder.dart

import 'dart:io';
import 'dart:math';
import 'dart:typed_data';
import 'dart:developer';

class ReportEncoder {}

Barrel files are not reported

export directives do not count, so a barrel of forty exports stays silent under the default budget:

// widgets.dart — 0 imports counted
export 'buttons.dart';
export 'cards.dart';
export 'dialogs.dart';

Set count_exports: true if you want a barrel held to the same budget.

Enabling this rule

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

many_lints.yaml

rules:
  max_imports:
    enabled: true

Options

analysis_options.yaml

analysis_options.yaml

many_lints:
  rules:
    max_imports:
      max_imports: 15
      count_exports: false

many_lints.yaml

many_lints.yaml

rules:
  max_imports:
    max_imports: 15
    count_exports: false

Option	Type	Default	Description
max_imports	int	15	How many libraries a file may import
count_exports	bool	false	Whether export directives count toward the budget

Turning this rule off

To disable this rule:

many_lints.yaml

rules:
  max_imports: false

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

Related rules

• avoid_long_files — Keep a file within a line budget.
• avoid_long_parameter_list — Keep parameter lists within a budget.
• avoid_too_many_methods — Keep a class within a method budget.
• max_statements — Keep a function within a statement budget.