chore: linting

2021-10-18 10:51:06 +02:00
parent 3a7343904d
commit 51e0b90f94
12 changed files with 333 additions and 358 deletions
@@ -46,12 +46,12 @@ class _RegistryWidgetState extends State<RegistryWidget> {
 }

 class _InheritedRegistryWidget extends InheritedWidget {
-  final _RegistryWidgetState state;
-
  const _InheritedRegistryWidget(
      {Key? key, required this.state, required Widget child})
      : super(key: key, child: child);

+  final _RegistryWidgetState state;
+
  @override
  bool updateShouldNotify(InheritedWidget oldWidget) => true;
 }
@@ -2,10 +2,13 @@ import 'dart:ui' show hashValues;

 import 'package:flutter/foundation.dart';

+/// {@template indexed_key}
+/// Creates an indexed key that delegates its [operator==] to the given key.
+///
+/// It contains an index used in [ScrollablePositionedList].
+/// {@endtemplate}
 class IndexedKey extends LocalKey {
-  /// Creates an indexed key that delegates its [operator==] to the given key.
-  ///
-  /// It contains an index used in [ScrollablePositionedList].
+  /// {@macro indexed_key}
  const IndexedKey(this.key, this.index);

  /// The key to which this this delegates its [operator==].
@@ -24,7 +27,5 @@ class IndexedKey extends LocalKey {
  int get hashCode => hashValues(runtimeType, key);

  @override
-  String toString() {
-    return '(IndexedKey) index: $index, key: $key';
-  }
+  String toString() => '(IndexedKey) index: $index, key: $key';
 }
@@ -4,8 +4,8 @@

 import 'package:flutter/foundation.dart';

-import 'item_positions_notifier.dart';
-import 'scrollable_positioned_list.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/item_positions_notifier.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/scrollable_positioned_list.dart';

 /// Provides a listenable iterable of [itemPositions] of items that are on
 /// screen and their locations.
@@ -57,5 +57,5 @@ class ItemPosition {

  @override
  String toString() =>
-      'ItemPosition(index: $index, itemLeadingEdge: $itemLeadingEdge, itemTrailingEdge: $itemTrailingEdge)';
+      '''ItemPosition(index: $index, itemLeadingEdge: $itemLeadingEdge, itemTrailingEdge: $itemTrailingEdge)''';
 }
@@ -4,7 +4,7 @@

 import 'package:flutter/foundation.dart';

-import 'item_positions_listener.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/item_positions_listener.dart';

 /// Internal implementation of [ItemPositionsListener].
 class ItemPositionsNotifier implements ItemPositionsListener {
@@ -8,11 +8,11 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/widgets.dart';

-import 'element_registry.dart';
-import 'indexed_key.dart';
-import 'item_positions_listener.dart';
-import 'item_positions_notifier.dart';
-import 'scroll_view.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/element_registry.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/indexed_key.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/item_positions_listener.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/item_positions_notifier.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/scroll_view.dart';

 /// A list of widgets similar to [ListView], except scroll control
 /// and position reporting is based on index rather than pixel offset.
@@ -27,6 +27,7 @@ import 'scroll_view.dart';
 class PositionedList extends StatefulWidget {
  /// Create a [PositionedList].
  const PositionedList({
+    Key? key,
    required this.itemCount,
    required this.itemBuilder,
    this.separatorBuilder,
@@ -44,11 +45,12 @@ class PositionedList extends StatefulWidget {
    this.addSemanticIndexes = true,
    this.addRepaintBoundaries = true,
    this.addAutomaticKeepAlives = true,
-  })  : assert(itemCount != null),
-        assert(itemBuilder != null),
-        assert((positionedIndex == 0) || (positionedIndex < itemCount));
+  })  : assert((positionedIndex == 0) || (positionedIndex < itemCount),
+            'positionedIndex cannot be 0 and must be smaller than itemCount'),
+        super(key: key);

-  /// Called to find the new index of a child based on its key in case of reordering.
+  /// Called to find the new index of a child based on its key in case of
+  /// reordering.
  ///
  /// If not provided, a child widget may not map to its existing [RenderObject]
  /// when the order in which children are returned from [builder] changes.
@@ -263,7 +265,7 @@ class _PositionedListState extends State<PositionedList> {
          : widget.reverse
              ? widget.padding?.copyWith(left: 0)
              : widget.padding?.copyWith(right: 0)) ??
-      EdgeInsets.all(0);
+      const EdgeInsets.all(0);

  EdgeInsets get _centerSliverPadding => widget.scrollDirection == Axis.vertical
      ? widget.reverse
@@ -274,13 +276,13 @@ class _PositionedListState extends State<PositionedList> {
                  bottom: widget.positionedIndex == 0
                      ? widget.padding!.bottom
                      : 0) ??
-              EdgeInsets.all(0)
+              const EdgeInsets.all(0)
          : widget.padding?.copyWith(
                  top: widget.positionedIndex == 0 ? widget.padding!.top : 0,
                  bottom: widget.positionedIndex == widget.itemCount - 1
                      ? widget.padding!.bottom
                      : 0) ??
-              EdgeInsets.all(0)
+              const EdgeInsets.all(0)
      : widget.reverse
          ? widget.padding?.copyWith(
                  left: widget.positionedIndex == widget.itemCount - 1
@@ -289,23 +291,23 @@ class _PositionedListState extends State<PositionedList> {
                  right: widget.positionedIndex == 0
                      ? widget.padding!.right
                      : 0) ??
-              EdgeInsets.all(0)
+              const EdgeInsets.all(0)
          : widget.padding?.copyWith(
                left: widget.positionedIndex == 0 ? widget.padding!.left : 0,
                right: widget.positionedIndex == widget.itemCount - 1
                    ? widget.padding!.right
                    : 0,
              ) ??
-              EdgeInsets.all(0);
+              const EdgeInsets.all(0);

  EdgeInsets get _trailingSliverPadding =>
      widget.scrollDirection == Axis.vertical
          ? widget.reverse
-              ? widget.padding?.copyWith(bottom: 0) ?? EdgeInsets.all(0)
-              : widget.padding?.copyWith(top: 0) ?? EdgeInsets.all(0)
+              ? widget.padding?.copyWith(bottom: 0) ?? const EdgeInsets.all(0)
+              : widget.padding?.copyWith(top: 0) ?? const EdgeInsets.all(0)
          : widget.reverse
-              ? widget.padding?.copyWith(right: 0) ?? EdgeInsets.all(0)
-              : widget.padding?.copyWith(left: 0) ?? EdgeInsets.all(0);
+              ? widget.padding?.copyWith(right: 0) ?? const EdgeInsets.all(0)
+              : widget.padding?.copyWith(left: 0) ?? const EdgeInsets.all(0);

  void _schedulePositionNotificationUpdate() {
    if (!updateScheduled) {
@@ -317,10 +319,10 @@ class _PositionedListState extends State<PositionedList> {
        }
        final positions = <ItemPosition>[];
        RenderViewport? viewport;
-        for (var element in registeredElements.value!) {
-          final RenderBox box = element.renderObject as RenderBox;
+        for (final element in registeredElements.value!) {
+          final box = element.renderObject as RenderBox;
          viewport ??= RenderAbstractViewport.of(box) as RenderViewport?;
-          final IndexedKey key = element.widget.key as IndexedKey;
+          final key = element.widget.key as IndexedKey;
          if (widget.scrollDirection == Axis.vertical) {
            final reveal = viewport!.getOffsetToReveal(box, 0).offset;
            final itemOffset = reveal -
@@ -29,7 +29,7 @@ class _PostMountCallbackElement extends StatelessElement {
  @override
  void mount(Element? parent, dynamic newSlot) {
    super.mount(parent, newSlot);
-    final PostMountCallback postMountCallback = widget as PostMountCallback;
+    final postMountCallback = widget as PostMountCallback;
    postMountCallback.callback?.call();
  }
 }
@@ -6,11 +6,14 @@ import 'package:flutter/gestures.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';

-import 'viewport.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/viewport.dart';

-/// A version of [CustomScrollView] that allows does not constrict the extents
+/// {@template custom_scroll_view}
+/// A version of [CustomScrollView] that does not constrict the extents
 /// to be within 0 and 1. See [CustomScrollView] for more information.
+/// {@endtemplate}
 class UnboundedCustomScrollView extends CustomScrollView {
+  /// {@macro custom_scroll_view}
  const UnboundedCustomScrollView({
    Key? key,
    Axis scrollDirection = Axis.vertical,
@@ -10,10 +10,10 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/widgets.dart';

-import 'item_positions_listener.dart';
-import 'item_positions_notifier.dart';
-import 'positioned_list.dart';
-import 'post_mount_callback.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/item_positions_listener.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/item_positions_notifier.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/positioned_list.dart';
+import 'package:stream_chat_flutter/src/scrollable_positioned_list/src/post_mount_callback.dart';

 /// Number of screens to scroll when scrolling a long distance.
 const int _screenScrollCount = 2;
@@ -52,9 +52,7 @@ class ScrollablePositionedList extends StatefulWidget {
    this.addRepaintBoundaries = true,
    this.minCacheExtent,
    this.findChildIndexCallback,
-  })  : assert(itemCount != null),
-        assert(itemBuilder != null),
-        itemPositionsNotifier = itemPositionsListener as ItemPositionsNotifier?,
+  })  : itemPositionsNotifier = itemPositionsListener as ItemPositionsNotifier?,
        separatorBuilder = null,
        super(key: key);

@@ -79,13 +77,12 @@ class ScrollablePositionedList extends StatefulWidget {
    this.addRepaintBoundaries = true,
    this.minCacheExtent,
    this.findChildIndexCallback,
-  })  : assert(itemCount != null),
-        assert(itemBuilder != null),
-        assert(separatorBuilder != null),
+  })  : assert(separatorBuilder != null, 'seperatorBuilder cannot be null'),
        itemPositionsNotifier = itemPositionsListener as ItemPositionsNotifier?,
        super(key: key);

-  /// Called to find the new index of a child based on its key in case of reordering.
+  /// Called to find the new index of a child based on its key in case of
+  /// reordering.
  ///
  /// If not provided, a child widget may not map to its existing [RenderObject]
  /// when the order in which children are returned from [builder] changes.
@@ -235,9 +232,11 @@ class ItemScrollController {
    Curve curve = Curves.linear,
    List<double> opacityAnimationWeights = const [40, 20, 40],
  }) {
-    assert(_scrollableListState != null);
-    assert(opacityAnimationWeights.length == 3);
-    assert(duration > Duration.zero);
+    assert(_scrollableListState != null, '_scrollableListState cannot be null');
+    assert(opacityAnimationWeights.length == 3,
+        'opacityAnimationWeights.length is not equal to 3');
+    assert(duration > Duration.zero,
+        'duration needs to be bigger than Duration.zero');
    return _scrollableListState!._scrollTo(
      index: index,
      alignment: alignment,
@@ -248,7 +247,8 @@ class ItemScrollController {
  }

  void _attach(_ScrollablePositionedListState scrollableListState) {
-    assert(_scrollableListState == null);
+    assert(
+        _scrollableListState == null, '_scrollableListState needs to be null');
    _scrollableListState = scrollableListState;
  }

@@ -260,11 +260,11 @@ class ItemScrollController {
 class _ScrollablePositionedListState extends State<ScrollablePositionedList>
    with TickerProviderStateMixin {
  /// Details for the primary (active) [ListView].
-  var primary = _ListDisplayDetails(const ValueKey('Ping'));
+  _ListDisplayDetails primary = _ListDisplayDetails(const ValueKey('Ping'));

  /// Details for the secondary (transitional) [ListView] that is temporarily
  /// shown when scrolling a long distance.
-  var secondary = _ListDisplayDetails(const ValueKey('Pong'));
+  _ListDisplayDetails secondary = _ListDisplayDetails(const ValueKey('Pong'));

  final opacity = ProxyAnimation(const AlwaysStoppedAnimation<double>(0));

@@ -275,10 +275,11 @@ class _ScrollablePositionedListState extends State<ScrollablePositionedList>
  @override
  void initState() {
    super.initState();
-    ItemPosition? initialPosition = PageStorage.of(context)!.readState(context);
-    primary.target = initialPosition?.index ?? widget.initialScrollIndex;
-    primary.alignment =
-        initialPosition?.itemLeadingEdge ?? widget.initialAlignment;
+    final ItemPosition? initialPosition =
+        PageStorage.of(context)!.readState(context);
+    primary
+      ..target = initialPosition?.index ?? widget.initialScrollIndex
+      ..alignment = initialPosition?.itemLeadingEdge ?? widget.initialAlignment;
    if (widget.itemCount > 0 && primary.target > widget.itemCount - 1) {
      primary.target = widget.itemCount - 1;
    }
@@ -333,79 +334,78 @@ class _ScrollablePositionedListState extends State<ScrollablePositionedList>
  }

  @override
-  Widget build(BuildContext context) {
-    return LayoutBuilder(
-      builder: (context, constraints) {
-        final cacheExtent = _cacheExtent(constraints);
-        return GestureDetector(
-          onPanDown: (_) => _stopScroll(canceled: true),
-          excludeFromSemantics: true,
-          child: Stack(
-            children: <Widget>[
-              PostMountCallback(
-                key: primary.key,
-                callback: startAnimationCallback,
-                child: FadeTransition(
-                  opacity: ReverseAnimation(opacity),
-                  child: NotificationListener<ScrollNotification>(
-                    onNotification: (_) => _isTransitioning,
-                    child: PositionedList(
-                      itemBuilder: widget.itemBuilder,
-                      separatorBuilder: widget.separatorBuilder,
-                      itemCount: widget.itemCount,
-                      positionedIndex: primary.target,
-                      controller: primary.scrollController,
-                      itemPositionsNotifier: primary.itemPositionsNotifier,
-                      scrollDirection: widget.scrollDirection,
-                      reverse: widget.reverse,
-                      cacheExtent: cacheExtent,
-                      alignment: primary.alignment,
-                      physics: widget.physics,
-                      addSemanticIndexes: widget.addSemanticIndexes,
-                      semanticChildCount: widget.semanticChildCount,
-                      padding: widget.padding,
-                      addAutomaticKeepAlives: widget.addAutomaticKeepAlives,
-                      addRepaintBoundaries: widget.addRepaintBoundaries,
-                      findChildIndexCallback: widget.findChildIndexCallback,
-                    ),
-                  ),
-                ),
-              ),
-              if (_isTransitioning)
+  Widget build(BuildContext context) => LayoutBuilder(
+        builder: (context, constraints) {
+          final cacheExtent = _cacheExtent(constraints);
+          return GestureDetector(
+            onPanDown: (_) => _stopScroll(canceled: true),
+            excludeFromSemantics: true,
+            child: Stack(
+              children: <Widget>[
                PostMountCallback(
-                  key: secondary.key,
+                  key: primary.key,
                  callback: startAnimationCallback,
                  child: FadeTransition(
-                    opacity: opacity,
+                    opacity: ReverseAnimation(opacity),
                    child: NotificationListener<ScrollNotification>(
-                      onNotification: (_) => false,
+                      onNotification: (_) => _isTransitioning,
                      child: PositionedList(
                        itemBuilder: widget.itemBuilder,
                        separatorBuilder: widget.separatorBuilder,
                        itemCount: widget.itemCount,
-                        itemPositionsNotifier: secondary.itemPositionsNotifier,
-                        positionedIndex: secondary.target,
-                        controller: secondary.scrollController,
+                        positionedIndex: primary.target,
+                        controller: primary.scrollController,
+                        itemPositionsNotifier: primary.itemPositionsNotifier,
                        scrollDirection: widget.scrollDirection,
                        reverse: widget.reverse,
                        cacheExtent: cacheExtent,
-                        alignment: secondary.alignment,
+                        alignment: primary.alignment,
                        physics: widget.physics,
                        addSemanticIndexes: widget.addSemanticIndexes,
                        semanticChildCount: widget.semanticChildCount,
                        padding: widget.padding,
                        addAutomaticKeepAlives: widget.addAutomaticKeepAlives,
                        addRepaintBoundaries: widget.addRepaintBoundaries,
+                        findChildIndexCallback: widget.findChildIndexCallback,
                      ),
                    ),
                  ),
                ),
-            ],
-          ),
-        );
-      },
-    );
-  }
+                if (_isTransitioning)
+                  PostMountCallback(
+                    key: secondary.key,
+                    callback: startAnimationCallback,
+                    child: FadeTransition(
+                      opacity: opacity,
+                      child: NotificationListener<ScrollNotification>(
+                        onNotification: (_) => false,
+                        child: PositionedList(
+                          itemBuilder: widget.itemBuilder,
+                          separatorBuilder: widget.separatorBuilder,
+                          itemCount: widget.itemCount,
+                          itemPositionsNotifier:
+                              secondary.itemPositionsNotifier,
+                          positionedIndex: secondary.target,
+                          controller: secondary.scrollController,
+                          scrollDirection: widget.scrollDirection,
+                          reverse: widget.reverse,
+                          cacheExtent: cacheExtent,
+                          alignment: secondary.alignment,
+                          physics: widget.physics,
+                          addSemanticIndexes: widget.addSemanticIndexes,
+                          semanticChildCount: widget.semanticChildCount,
+                          padding: widget.padding,
+                          addAutomaticKeepAlives: widget.addAutomaticKeepAlives,
+                          addRepaintBoundaries: widget.addRepaintBoundaries,
+                        ),
+                      ),
+                    ),
+                  ),
+              ],
+            ),
+          );
+        },
+      );

  double _cacheExtent(BoxConstraints constraints) => max(
        constraints.maxHeight * _screenScrollCount,
@@ -419,8 +419,9 @@ class _ScrollablePositionedListState extends State<ScrollablePositionedList>
    }
    setState(() {
      primary.scrollController.jumpTo(0);
-      primary.target = index;
-      primary.alignment = alignment;
+      primary
+        ..target = index
+        ..alignment = alignment;
    });
  }

@@ -505,8 +506,9 @@ class _ScrollablePositionedListState extends State<ScrollablePositionedList>
      setState(() {
        // TODO: _startScroll can be re-entrant, which invalidates this assert.
        // assert(!_isTransitioning);
-        secondary.target = index;
-        secondary.alignment = alignment;
+        secondary
+          ..target = index
+          ..alignment = alignment;
        _isTransitioning = true;
      });
      await Future.wait<void>([startCompleter.future, endCompleter.future]);
@@ -532,7 +534,7 @@ class _ScrollablePositionedListState extends State<ScrollablePositionedList>
      if (opacity.value >= 0.5) {
        // Secondary [ListView] is more visible than the primary; make it the
        // new primary.
-        var temp = primary;
+        final temp = primary;
        primary = secondary;
        secondary = temp;
      }
@@ -542,8 +544,8 @@ class _ScrollablePositionedListState extends State<ScrollablePositionedList>
  }

  Animatable<double> _opacityAnimation(List<double> opacityAnimationWeights) {
-    final startOpacity = 0.0;
-    final endOpacity = 1.0;
+    const startOpacity = 0.0;
+    const endOpacity = 1.0;
    return TweenSequence<double>(<TweenSequenceItem<double>>[
      TweenSequenceItem<double>(
          tween: ConstantTween<double>(startOpacity),
@@ -2,17 +2,22 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

+// ignore_for_file: lines_longer_than_80_chars
+
 import 'dart:math' as math;

 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';

+/// {@template unbounded_viewport}
 /// A render object that is bigger on the inside.
 ///
 /// Version of [Viewport] with some modifications to how extents are
 /// computed to allow scroll extents outside 0 to 1.  See [Viewport]
 /// for more information.
+/// description
 class UnboundedViewport extends Viewport {
+  /// {@macro unbounded_viewport}
  UnboundedViewport({
    Key? key,
    AxisDirection axisDirection = AxisDirection.down,
@@ -40,16 +45,15 @@ class UnboundedViewport extends Viewport {
  double get anchor => _anchor;

  @override
-  RenderViewport createRenderObject(BuildContext context) {
-    return UnboundedRenderViewport(
-      axisDirection: axisDirection,
-      crossAxisDirection: crossAxisDirection ??
-          Viewport.getDefaultCrossAxisDirection(context, axisDirection),
-      anchor: anchor,
-      offset: offset,
-      cacheExtent: cacheExtent,
-    );
-  }
+  RenderViewport createRenderObject(BuildContext context) =>
+      UnboundedRenderViewport(
+        axisDirection: axisDirection,
+        crossAxisDirection: crossAxisDirection ??
+            Viewport.getDefaultCrossAxisDirection(context, axisDirection),
+        anchor: anchor,
+        offset: offset,
+        cacheExtent: cacheExtent,
+      );
 }

 /// A render object that is bigger on the inside.
@@ -100,7 +104,6 @@ class UnboundedRenderViewport extends RenderViewport {

  @override
  set anchor(double value) {
-    assert(value != null);
    if (value == _anchor) return;
    _anchor = value;
    markNeedsLayout();
@@ -124,8 +127,6 @@ class UnboundedRenderViewport extends RenderViewport {

  @override
  Rect describeSemanticsClip(RenderSliver? child) {
-    assert(axis != null);
-
    if (_calculatedCacheExtent == null) {
      return semanticBounds;
    }
@@ -151,14 +152,14 @@ class UnboundedRenderViewport extends RenderViewport {
  @override
  void performLayout() {
    if (center == null) {
-      assert(firstChild == null);
+      assert(firstChild == null, 'firstChild cannot be null');
      _minScrollExtent = 0.0;
      _maxScrollExtent = 0.0;
      _hasVisualOverflow = false;
-      offset.applyContentDimensions(0.0, 0.0);
+      offset.applyContentDimensions(0, 0);
      return;
    }
-    assert(center!.parent == this);
+    assert(center!.parent == this, 'center.parent cannot be equal to this');

    late double mainAxisExtent;
    late double crossAxisExtent;
@@ -178,7 +179,6 @@ class UnboundedRenderViewport extends RenderViewport {
    double correction;
    var count = 0;
    do {
-      assert(offset.pixels != null);
      correction = _attemptLayout(mainAxisExtent, crossAxisExtent,
          offset.pixels + centerOffsetAdjustment);
      if (correction != 0.0) {
@@ -187,17 +187,18 @@ class UnboundedRenderViewport extends RenderViewport {
        // *** Difference from [RenderViewport].
        final top = _minScrollExtent + mainAxisExtent * anchor;
        final bottom = _maxScrollExtent - mainAxisExtent * (1.0 - anchor);
-        final maxScrollOffset = math.max(math.min(0.0, top), bottom);
-        final minScrollOffset = math.min(top, maxScrollOffset);
-        if (offset.applyContentDimensions(minScrollOffset, maxScrollOffset))
+        final maxScrollOffset = math.max<double>(math.min(0, top), bottom);
+        final minScrollOffset = math.min<double>(top, maxScrollOffset);
+        if (offset.applyContentDimensions(minScrollOffset, maxScrollOffset)) {
          break;
+        }
        // *** End of difference from [RenderViewport].
      }
      count += 1;
    } while (count < _maxLayoutCycles);
    assert(() {
      if (count >= _maxLayoutCycles) {
-        assert(count != 1);
+        assert(count != 1, 'count not equal to 1');
        throw FlutterError(
            'A RenderViewport exceeded its maximum number of layout cycles.\n'
            'RenderViewport render objects, during layout, can retry if either their '
@@ -217,16 +218,16 @@ class UnboundedRenderViewport extends RenderViewport {
            ' layout passes.');
      }
      return true;
-    }());
+    }(), 'count needs to be bigger than _maxLayoutCycles');
  }

  double _attemptLayout(
      double mainAxisExtent, double crossAxisExtent, double correctedOffset) {
-    assert(!mainAxisExtent.isNaN);
-    assert(mainAxisExtent >= 0.0);
-    assert(crossAxisExtent.isFinite);
-    assert(crossAxisExtent >= 0.0);
-    assert(correctedOffset.isFinite);
+    assert(!mainAxisExtent.isNaN, 'assert mainAxisExtent.isNaN');
+    assert(mainAxisExtent >= 0.0, 'assert mainAxisExtent >= 0.0');
+    assert(crossAxisExtent.isFinite, 'assert crossAxisExtent.isFinite');
+    assert(crossAxisExtent >= 0.0, 'assert crossAxisExtent >= 0.0');
+    assert(correctedOffset.isFinite, 'assert correctedOffset.isFinite');
    _minScrollExtent = 0.0;
    _maxScrollExtent = 0.0;
    _hasVisualOverflow = false;
@@ -234,10 +235,10 @@ class UnboundedRenderViewport extends RenderViewport {
    // centerOffset is the offset from the leading edge of the RenderViewport
    // to the zero scroll offset (the line between the forward slivers and the
    // reverse slivers).
-    final double centerOffset = mainAxisExtent * anchor - correctedOffset;
-    final double reverseDirectionRemainingPaintExtent =
+    final centerOffset = mainAxisExtent * anchor - correctedOffset;
+    final reverseDirectionRemainingPaintExtent =
        centerOffset.clamp(0.0, mainAxisExtent);
-    final double forwardDirectionRemainingPaintExtent =
+    final forwardDirectionRemainingPaintExtent =
        (mainAxisExtent - centerOffset).clamp(0.0, mainAxisExtent);

    switch (cacheExtentStyle) {
@@ -249,21 +250,21 @@ class UnboundedRenderViewport extends RenderViewport {
        break;
    }

-    final double fullCacheExtent = mainAxisExtent + 2 * _calculatedCacheExtent!;
-    final double centerCacheOffset = centerOffset + _calculatedCacheExtent!;
-    final double reverseDirectionRemainingCacheExtent =
+    final fullCacheExtent = mainAxisExtent + 2 * _calculatedCacheExtent!;
+    final centerCacheOffset = centerOffset + _calculatedCacheExtent!;
+    final reverseDirectionRemainingCacheExtent =
        centerCacheOffset.clamp(0.0, fullCacheExtent);
-    final double forwardDirectionRemainingCacheExtent =
+    final forwardDirectionRemainingCacheExtent =
        (fullCacheExtent - centerCacheOffset).clamp(0.0, fullCacheExtent);

-    final RenderSliver? leadingNegativeChild = childBefore(center!);
+    final leadingNegativeChild = childBefore(center!);

    if (leadingNegativeChild != null) {
      // negative scroll offsets
-      final double result = layoutChildSequence(
+      final result = layoutChildSequence(
        child: leadingNegativeChild,
        scrollOffset: math.max(mainAxisExtent, centerOffset) - mainAxisExtent,
-        overlap: 0.0,
+        overlap: 0,
        layoutOffset: forwardDirectionRemainingPaintExtent,
        remainingPaintExtent: reverseDirectionRemainingPaintExtent,
        mainAxisExtent: mainAxisExtent,
@@ -280,9 +281,8 @@ class UnboundedRenderViewport extends RenderViewport {
    // positive scroll offsets
    return layoutChildSequence(
      child: center,
-      scrollOffset: math.max(0.0, -centerOffset),
-      overlap:
-          leadingNegativeChild == null ? math.min(0.0, -centerOffset) : 0.0,
+      scrollOffset: math.max(0, -centerOffset),
+      overlap: leadingNegativeChild == null ? math.min(0, -centerOffset) : 0.0,
      layoutOffset: centerOffset >= mainAxisExtent
          ? centerOffset
          : reverseDirectionRemainingPaintExtent,