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prefer-define-hero-tag

Group: Correctness
Path: lint/correctness/prefer-define-hero-tag
Default: Off, opt in
Origin: Falcon
Domain: flutter
Rule: 347 of 512

flutter

Require an explicit heroTag on Flutter FloatingActionButton constructors.

The default tag is shared, so multiple buttons can collide during a Hero transition. Set a unique tag or explicitly pass null to disable the transition. Includes unnamed, small, large, and extended constructors; package identities exclude local lookalikes and shadowed names. Matches the DCM rule of this id.

Invalid

example.dartdart

import 'package:flutter/material.dart';
import 'package:flutter/material.dart' as f;

typedef Action = FloatingActionButton;
void actions() {
  FloatingActionButton();
  new FloatingActionButton.small();
  const f.FloatingActionButton.large();
  FloatingActionButton.extended(label: Text('Add'));
  Action();
}

Provide an explicit `heroTag` for this floating action button.

5void actions() {

6 FloatingActionButton();

∙

Provide an explicit `heroTag` for this floating action button.

6 FloatingActionButton();

7 new FloatingActionButton.small();

∙

Provide an explicit `heroTag` for this floating action button.

7 new FloatingActionButton.small();

8 const f.FloatingActionButton.large();

∙

Provide an explicit `heroTag` for this floating action button.

8 const f.FloatingActionButton.large();

9 FloatingActionButton.extended(label: Text('Add'));

∙

Provide an explicit `heroTag` for this floating action button.

9 FloatingActionButton.extended(label: Text('Add'));

10 Action();

∙

Valid

example.dartdart

import 'package:flutter/material.dart';
import 'package:flutter/material.dart' as f;

void actions(Object tag) {
  FloatingActionButton(heroTag: 'add');
  const FloatingActionButton.small(heroTag: 1);
  f.FloatingActionButton.large(heroTag: tag);
  FloatingActionButton.extended(label: Text('Add'), heroTag: null);
  FloatingActionButton(heroTag: (null));
  Hero(tag: 'flight');
}
void shadow(dynamic FloatingActionButton) { FloatingActionButton(); }

Configure prefer-define-hero-tag

Set its severity in falcon.json. See the configuration guide.

falcon.jsonjson

{
  "linter": {
    "rules": {
      "correctness": {
        "prefer-define-hero-tag": "error"
      }
    }
  }
}

Or silence one occurrence with a suppression comment; the reason is required.

example.dartdart

// falcon-ignore lint/correctness/prefer-define-hero-tag: <reason>

prefer-expect-latertest
Requires expectLater when a canonical expect call receives an unawaited Future.
prefer-immutable-bloc-eventsrecommendedbloc
Flags Bloc event classes without an explicit @immutable annotation.
prefer-immutable-bloc-staterecommendedbloc
Flags Bloc state classes without an explicit @immutable annotation.
prefer-immutable-provider-argumentsriverpod
Requires stable value equality for freshly created Riverpod family keys.
prefer-read-for-methodsrecommendedprovider
Flags void method actions on a listening Provider lookup during build.
prefer-ref-read-for-methodsrecommendedriverpod
Flags watching a Riverpod notifier solely to invoke one of its methods.
prefer-relative-importsprefer_relative_imports
Prefer relative imports for libraries of the same package under lib/.
prefer-sealed-bloc-eventsrecommendedbloc
Flags Bloc event classes without a sealed or final modifier.