avoid_wrapping_in_padding

v0.4.0 Warning Fix Widget Replacement

Flags a Padding whose child already takes a padding argument of its own — Container, ListView, GridView, SingleChildScrollView, ReorderableListView, Chip, and any of your own widgets that expose one. The wrapper is a whole extra render object doing what the child would have done for free.

The check is structural, not a fixed list: the rule looks at the child’s constructors and reports if any of them declares a named padding parameter.

Why use this rule

Each Padding in the tree is a RenderPadding to lay out and paint. When the child already accepts padding:, moving the value inward removes a level of nesting and a render object, and puts the inset next to the widget it belongs to. The quick fix does the move, carrying the key across if the Padding had one.

See also: Padding | ScrollView.padding

Don’t

// ListView takes its own padding. Wrapping it insets the whole viewport, so
// the scrollbar and the overscroll glow move inward with the content.
Padding(
  padding: EdgeInsets.all(16),
  child: ListView(children: items),
);

Do

// The inset now applies to the content; the viewport still fills the space.
ListView(padding: EdgeInsets.all(16), children: items);

Examples

Nothing here is hard-coded to Flutter’s widgets. Give a widget a padding parameter and the rule starts reporting Padding around it:

class Panel extends StatelessWidget {
  const Panel({super.key, this.padding, required this.child});

  final EdgeInsetsGeometry? padding;
  final Widget child;

  @override
  Widget build(BuildContext context) => Container(
    color: const Color(0xFFEEEEEE),
    padding: padding,
    child: child,
  );
}

// Don't — Panel declares `padding`, so the wrapper is redundant
Padding(padding: const EdgeInsets.all(8), child: Panel(child: body));

// Do
Panel(padding: const EdgeInsets.all(8), child: body);

Note that a padding parameter your widget then ignores will still make the rule report — it reads the constructor signature, not what build does with the value.

Wrapping a Container

Padding(padding: p, child: Container(child: x)) is reported here, and the mechanical fix — Container(padding: p, child: x) — is then reported by prefer_padding_over_container, which wants a bare Container carrying only padding turned back into a Padding. Both ship in opinionated.

For a Container with nothing else set, the answer is neither: drop the Container.

// Don't
Padding(padding: EdgeInsets.all(16), child: Container(child: Text('Hello')));

// Do — the Container was doing nothing
Padding(padding: EdgeInsets.all(16), child: Text('Hello'));

The two rules only collide on a Container that is otherwise empty. Once it is carrying a color or a decoration, prefer_padding_over_container is silent and moving the padding in is the right move:

// Don't
Padding(
  padding: EdgeInsets.all(16),
  child: Container(
    color: const Color(0xFFEEEEEE),
    child: const Text('Hello'),
  ),
);

// Do — reported by nothing
Container(
  color: const Color(0xFFEEEEEE),
  padding: EdgeInsets.all(16),
  child: const Text('Hello'),
);

Known limitations

A child that already sets padding is left alone. Merging two insets is a decision, not a rewrite:

// Not reported
Padding(
  padding: EdgeInsets.all(8),
  child: Container(padding: EdgeInsets.all(4), child: Text('Hello')),
);

A Padding with no child is never reported — there is nothing to move the value into.

Only the immediate child is examined. Padding > Center > ListView is not reported, even though the ListView could still take the inset, because moving it across the Center would change the layout.

Configuration

This rule is in the opinionated preset, so it is on with preset: opinionated, or by name:

rules:
  avoid_wrapping_in_padding: true

To turn it off again:

rules:
  avoid_wrapping_in_padding: false

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

prefer_padding_over_container — Use Padding instead of Container when only padding or margin is set.
avoid_border_all — Use Border.fromBorderSide instead of Border.all for const support.
avoid_expanded_as_spacer — Use Spacer instead of Expanded with an empty child.
avoid_incorrect_image_opacity — Use Image’s opacity parameter instead of wrapping in Opacity.