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Presets

Presets are predefined sets or rules/metrics (for example, for a particular package or for a particular set of problems) that help you quickly configure DCM.

info

While presets are a great way to keep track of rule list updates, upgrading to a newer version of DCM can introduce new issues if a preset has been updated.

Consider this before choosing a preset.

Built-in Presets

To simplify the tool's integration, some presets can be enabled without installing any additional package, for example, the "recommended" preset:

analysis_options.yaml

dcm:
  extends:
    - recommended

To enable recommended metrics, use the metrics-recommended preset:

analysis_options.yaml

dcm:
  extends:
    - metrics-recommended

note

Since built-in presets come with the executable, the list of the included rules or metrics depends on the executable version, but is expected to match the latest version located here and here.

Additionally, all rule tags are available as built-in presets. For example,

analysis_options.yaml

dcm:
  extends:
    - async
    - collections

will enable all these and these rules.

External Presets

Alternatively, you can install the dart_code_metrics_presets package that includes 20 presets, with 18 for lints:

• All: contains all available lint rules for Dart and Flutter.
• Recommended: contains recommended Dart and Flutter rules (with an emphasis on finding errors).
• Dart: contains all lint rules applicable to any Dart app.
• Flutter: contains all lint rules applicable to any Flutter app.
• Pub: contains lint rules to check for issues in the pubspec.yaml file.
• Flame: contains lint rules for the Flame package.
• Provider: contains lint rules for the Provider package.
• Bloc: contains lint rules for the Bloc package.
• Riverpod: contains lint rules for the Riverpod package.
• Equatable: contains lint rules for the Equatable package.
• Patrol: contains lint rules for the Patrol package.
• FakeAsync: contains lint rules for the FakeAsync package.
• GetIt: contains lint rules for the GetIt package.
• FlutterHooks: contains lint rules for the FlutterHooks package.
• FirebaseAnalytics: contains lint rules for the FirebaseAnalytics package.
• GetX: contains lint rules for the GetX package.
• Intl: contains lint rules for the Intl package.
• EasyLocalization: contains lint rules for the EasyLocalization package.

and 2 for metrics:

• All Metrics: contains all available metrics with recommended default thresholds.
• Recommended metrics: contains recommended metrics with default thresholds.

Enabling an External Preset

To enable a preset:

1. Install dart_code_metrics_presets as a dev dependency:

   Flutter

   $ flutter pub add --dev dart_code_metrics_presets

   Dart

   $ dart pub add --dev dart_code_metrics_presets

2. For DCM configuration add the extends entry:

   analysis_options.yaml

   dcm:
     extends:
       - package:dart_code_metrics_presets/all.yaml

info

If you are reusing a shared configuration between multiple packages, they should all have dart_code_metrics_presets as dev dependency.

info

If the preset cannot be resolved, a preset-not-found warning will be shown.

Reconfiguring a Rule

To reconfigure a rule included into a preset:

analysis_options.yaml

dcm:
  extends:
    - package:dart_code_metrics_presets/all.yaml
  rules:
    - arguments-ordering:
        child-last: true

Disabling a Rule

To disable a rule set its configuration to : false:

analysis_options.yaml

dcm:
  extends:
    - package:dart_code_metrics_presets/all.yaml
  rules:
    - avoid-banned-imports: false

Defining a Custom Preset

Creating custom presets is also supported. For example,

my_preset/analysis_options.yaml

dcm:
  extends:
    - package:dart_code_metrics_presets/all.yaml
    - package:dart_code_metrics_presets/teams_all.yaml

This defines a new preset that will load rules from dart_code_metrics_presets/all.yaml and dart_code_metrics_presets/teams_all.yaml.

To use this custom preset, add it to the extends section of another analysis_options file:

analysis_options.yaml

dcm:
  extends:
    - package:my_presets/analysis_options.yaml

What Structure a Custom Preset Should Have?

The only requirement for a preset is that it should match the regular DCM configuration structure. For example,

analysis_options.yaml

dcm:
  rules:
    - avoid-cubits
    - avoid-bloc-public-methods
    - avoid-passing-bloc-to-bloc
    - prefer-multi-bloc-provider
    - prefer-correct-bloc-provider

What Happens If a Rule Is Included Into Multiple Loaded Presets?

When configuration is loaded, the last subsequent entry overrides the previous one, meaning that if in dart_code_metrics_presets/all.yaml there is a rule called some-rule and in my_presets/analysis_options.yaml the same rule is disabled via some-rule: false, in the resulting config the rule will be disabled.

analysis_options.yaml

dcm:
  extends:
    - package:dart_code_metrics_presets/all.yaml
    - package:my_presets/analysis_options.yaml # disables 'some-rule' if listed last

Note, that the configuration in the analysis_options.yaml file that loads the presets is the primary configuration and overrides the loaded config:

analysis_options.yaml

dcm:
  extends:
    - package:dart_code_metrics_presets/all.yaml
    - package:my_presets/analysis_options.yaml
  rules:
    - some-rule: true # overrides any configuration from the presets