Remove unnecessary null checks in flutter/rendering (#118923)

Author: goderbauer

packages/flutter/lib/src/rendering/animated_size.dart

@@ -82,11 +82,7 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
     super.textDirection,
     super.child,
     Clip clipBehavior = Clip.hardEdge,
-  }) : assert(vsync != null),
-       assert(duration != null),
-       assert(curve != null),
-       assert(clipBehavior != null),
-       _vsync = vsync,
+  }) : _vsync = vsync,
        _clipBehavior = clipBehavior {
     _controller = AnimationController(
       vsync: vsync,
@@ -119,7 +115,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   /// The duration of the animation.
   Duration get duration => _controller.duration!;
   set duration(Duration value) {
-    assert(value != null);
     if (value == _controller.duration) {
       return;
     }
@@ -138,7 +133,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   /// The curve of the animation.
   Curve get curve => _animation.curve;
   set curve(Curve value) {
-    assert(value != null);
     if (value == _animation.curve) {
       return;
     }
@@ -151,7 +145,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior = Clip.hardEdge;
   set clipBehavior(Clip value) {
-    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsPaint();
@@ -169,7 +162,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   TickerProvider get vsync => _vsync;
   TickerProvider _vsync;
   set vsync(TickerProvider value) {
-    assert(value != null);
     if (value == _vsync) {
       return;
     }
@@ -218,7 +210,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
 
     child!.layout(constraints, parentUsesSize: true);
 
-    assert(_state != null);
     switch (_state) {
       case RenderAnimatedSizeState.start:
         _layoutStart();
@@ -253,7 +244,6 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
     // size without modifying global state. See performLayout for comments
     // explaining the rational behind the implementation.
     final Size childSize = child!.getDryLayout(constraints);
-    assert(_state != null);
     switch (_state) {
       case RenderAnimatedSizeState.start:
         return constraints.constrain(childSize);

packages/flutter/lib/src/rendering/binding.dart

@@ -43,7 +43,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
       ..onSemanticsAction = _handleSemanticsAction;
     initRenderView();
     _handleSemanticsEnabledChanged();
-    assert(renderView != null);
     addPersistentFrameCallback(_handlePersistentFrameCallback);
     initMouseTracker();
     if (kIsWeb) {
@@ -234,7 +233,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
   /// Sets the given [RenderView] object (which must not be null), and its tree, to
   /// be the new render tree to display. The previous tree, if any, is detached.
   set renderView(RenderView value) {
-    assert(value != null);
     _pipelineOwner.rootNode = value;
   }
 
@@ -244,7 +242,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
   @protected
   @visibleForTesting
   void handleMetricsChanged() {
-    assert(renderView != null);
     renderView.configuration = createViewConfiguration();
     if (renderView.child != null) {
       scheduleForcedFrame();
@@ -512,7 +509,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
   // When editing the above, also update widgets/binding.dart's copy.
   @protected
   void drawFrame() {
-    assert(renderView != null);
     pipelineOwner.flushLayout();
     pipelineOwner.flushCompositingBits();
     pipelineOwner.flushPaint();
@@ -544,9 +540,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
 
   @override
   void hitTest(HitTestResult result, Offset position) {
-    assert(renderView != null);
-    assert(result != null);
-    assert(position != null);
     renderView.hitTest(result, position: position);
     super.hitTest(result, position);
   }
@@ -620,7 +613,6 @@ class RenderingFlutterBinding extends BindingBase with GestureBinding, Scheduler
   /// This binding does not automatically schedule any frames. Callers are
   /// responsible for deciding when to first call [scheduleFrame].
   RenderingFlutterBinding({ RenderBox? root }) {
-    assert(renderView != null);
     renderView.child = root;
   }
 

packages/flutter/lib/src/rendering/box.dart

@@ -96,10 +96,7 @@ class BoxConstraints extends Constraints {
     this.maxWidth = double.infinity,
     this.minHeight = 0.0,
     this.maxHeight = double.infinity,
-  }) : assert(minWidth != null),
-       assert(maxWidth != null),
-       assert(minHeight != null),
-       assert(maxHeight != null);
+  });
 
   /// Creates box constraints that is respected only by the given size.
   BoxConstraints.tight(Size size)
@@ -190,7 +187,6 @@ class BoxConstraints extends Constraints {
 
   /// Returns new box constraints that are smaller by the given edge dimensions.
   BoxConstraints deflate(EdgeInsets edges) {
-    assert(edges != null);
     assert(debugAssertIsValid());
     final double horizontal = edges.horizontal;
     final double vertical = edges.vertical;
@@ -472,7 +468,6 @@ class BoxConstraints extends Constraints {
   ///
   /// {@macro dart.ui.shadow.lerp}
   static BoxConstraints? lerp(BoxConstraints? a, BoxConstraints? b, double t) {
-    assert(t != null);
     if (a == null && b == null) {
       return null;
     }
@@ -762,8 +757,6 @@ class BoxHitTestResult extends HitTestResult {
     required Offset position,
     required BoxHitTest hitTest,
   }) {
-    assert(position != null);
-    assert(hitTest != null);
     if (transform != null) {
       transform = Matrix4.tryInvert(PointerEvent.removePerspectiveTransform(transform));
       if (transform == null) {
@@ -801,8 +794,6 @@ class BoxHitTestResult extends HitTestResult {
     required Offset position,
     required BoxHitTest hitTest,
   }) {
-    assert(position != null);
-    assert(hitTest != null);
     final Offset transformedPosition = offset == null ? position : position - offset;
     if (offset != null) {
       pushOffset(-offset);
@@ -838,9 +829,6 @@ class BoxHitTestResult extends HitTestResult {
     required Offset position,
     required BoxHitTest hitTest,
   }) {
-    assert(position != null);
-    assert(hitTest != null);
-    assert(position != null);
     final Offset transformedPosition = transform == null ?
         position : MatrixUtils.transformPoint(transform, position);
     if (transform != null) {
@@ -887,7 +875,6 @@ class BoxHitTestResult extends HitTestResult {
     Matrix4? rawTransform,
     required BoxHitTestWithOutOfBandPosition hitTest,
   }) {
-    assert(hitTest != null);
     assert(
       (paintOffset == null && paintTransform == null && rawTransform != null) ||
       (paintOffset == null && paintTransform != null && rawTransform == null) ||
@@ -915,8 +902,7 @@ class BoxHitTestEntry extends HitTestEntry<RenderBox> {
   /// Creates a box hit test entry.
   ///
   /// The [localPosition] argument must not be null.
-  BoxHitTestEntry(super.target, this.localPosition)
-    : assert(localPosition != null);
+  BoxHitTestEntry(super.target, this.localPosition);
 
   /// The position of the hit test in the local coordinates of [target].
   final Offset localPosition;
@@ -1452,13 +1438,6 @@ abstract class RenderBox extends RenderObject {
   @mustCallSuper
   double getMinIntrinsicWidth(double height) {
     assert(() {
-      if (height == null) {
-        throw FlutterError.fromParts(<DiagnosticsNode>[
-          ErrorSummary('The height argument to getMinIntrinsicWidth was null.'),
-          ErrorDescription('The argument to getMinIntrinsicWidth must not be negative or null.'),
-          ErrorHint('If you do not have a specific height in mind, then pass double.infinity instead.'),
-        ]);
-      }
       if (height < 0.0) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary('The height argument to getMinIntrinsicWidth was negative.'),
@@ -1601,13 +1580,6 @@ abstract class RenderBox extends RenderObject {
   @mustCallSuper
   double getMaxIntrinsicWidth(double height) {
     assert(() {
-      if (height == null) {
-        throw FlutterError.fromParts(<DiagnosticsNode>[
-          ErrorSummary('The height argument to getMaxIntrinsicWidth was null.'),
-          ErrorDescription('The argument to getMaxIntrinsicWidth must not be negative or null.'),
-          ErrorHint('If you do not have a specific height in mind, then pass double.infinity instead.'),
-        ]);
-      }
       if (height < 0.0) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary('The height argument to getMaxIntrinsicWidth was negative.'),
@@ -1684,13 +1656,6 @@ abstract class RenderBox extends RenderObject {
   @mustCallSuper
   double getMinIntrinsicHeight(double width) {
     assert(() {
-      if (width == null) {
-        throw FlutterError.fromParts(<DiagnosticsNode>[
-          ErrorSummary('The width argument to getMinIntrinsicHeight was null.'),
-          ErrorDescription('The argument to getMinIntrinsicHeight must not be negative or null.'),
-          ErrorHint('If you do not have a specific width in mind, then pass double.infinity instead.'),
-        ]);
-      }
       if (width < 0.0) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary('The width argument to getMinIntrinsicHeight was negative.'),
@@ -1766,13 +1731,6 @@ abstract class RenderBox extends RenderObject {
   @mustCallSuper
   double getMaxIntrinsicHeight(double width) {
     assert(() {
-      if (width == null) {
-        throw FlutterError.fromParts(<DiagnosticsNode>[
-          ErrorSummary('The width argument to getMaxIntrinsicHeight was null.'),
-          ErrorDescription('The argument to getMaxIntrinsicHeight must not be negative or null.'),
-          ErrorHint('If you do not have a specific width in mind, then pass double.infinity instead.'),
-        ]);
-      }
       if (width < 0.0) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary('The width argument to getMaxIntrinsicHeight was negative.'),
@@ -2253,7 +2211,6 @@ abstract class RenderBox extends RenderObject {
 
   @override
   void debugAssertDoesMeetConstraints() {
-    assert(constraints != null);
     assert(() {
       if (!hasSize) {
         final DiagnosticsNode contract;
@@ -2582,7 +2539,6 @@ abstract class RenderBox extends RenderObject {
   /// child's [parentData] in the [BoxParentData.offset] field.
   @override
   void applyPaintTransform(RenderObject child, Matrix4 transform) {
-    assert(child != null);
     assert(child.parent == this);
     assert(() {
       if (child.parentData is! BoxParentData) {

packages/flutter/lib/src/rendering/custom_layout.dart

@@ -187,11 +187,6 @@ abstract class MultiChildLayoutDelegate {
           'There is no child with the id "$childId".',
         );
       }
-      if (offset == null) {
-        throw FlutterError(
-          'The $this custom multichild layout delegate provided a null position for the child with id "$childId".',
-        );
-      }
       return true;
     }());
     final MultiChildLayoutParentData childParentData = child!.parentData! as MultiChildLayoutParentData;
@@ -311,8 +306,7 @@ class RenderCustomMultiChildLayoutBox extends RenderBox
   RenderCustomMultiChildLayoutBox({
     List<RenderBox>? children,
     required MultiChildLayoutDelegate delegate,
-  }) : assert(delegate != null),
-       _delegate = delegate {
+  }) : _delegate = delegate {
     addAll(children);
   }
 
@@ -327,7 +321,6 @@ class RenderCustomMultiChildLayoutBox extends RenderBox
   MultiChildLayoutDelegate get delegate => _delegate;
   MultiChildLayoutDelegate _delegate;
   set delegate(MultiChildLayoutDelegate newDelegate) {
-    assert(newDelegate != null);
     if (_delegate == newDelegate) {
       return;
     }

packages/flutter/lib/src/rendering/custom_paint.dart

@@ -294,8 +294,7 @@ class CustomPainterSemantics {
     required this.properties,
     this.transform,
     this.tags,
-  }) : assert(rect != null),
-       assert(properties != null);
+  });
 
   /// Identifies this object in a list of siblings.
   ///
@@ -371,8 +370,7 @@ class RenderCustomPaint extends RenderProxyBox {
     this.isComplex = false,
     this.willChange = false,
     RenderBox? child,
-  }) : assert(preferredSize != null),
-       _painter = painter,
+  }) : _painter = painter,
        _foregroundPainter = foregroundPainter,
        _preferredSize = preferredSize,
        super(child);
@@ -467,7 +465,6 @@ class RenderCustomPaint extends RenderProxyBox {
   Size get preferredSize => _preferredSize;
   Size _preferredSize;
   set preferredSize(Size value) {
-    assert(value != null);
     if (preferredSize == value) {
       return;
     }