SliverGeometry is not valid: The "layoutExtent" exceeds the "paintExtent"

[per-johansson-74]

When I scroll up/down couple of times that happens, Seems to be a rounding error.

If I comment layoutExtent in line 74 lib/src/rendering.dart so that it uses paintExtent instead the issue seems solved. No more errors and everything seems to work fine for me.

geometry = SliverGeometry(
      scrollExtent: maxExtent,
      paintOrigin: constraints.overlap,
      paintExtent: math.min(childExtent, effectiveRemainingPaintExtent),
      //layoutExtent: layoutExtent,
      maxPaintExtent: maxExtent,
      maxScrollObstructionExtent: minExtent,
      cacheExtent: layoutExtent > 0.0
          ? -constraints.cacheOrigin + layoutExtent
          : layoutExtent,
      hasVisualOverflow:
          true, // Conservatively say we do have overflow to avoid complexity.
    );

Here is couple examples: The paintExtent is 74.6651785714286, but the layoutExtent is 74.66517857142861 The paintExtent is 148.74255952380966, but the layoutExtent is 148.7425595238097

The following assertion was thrown during performLayout():
SliverGeometry is not valid: The "layoutExtent" exceeds the "paintExtent".

The paintExtent is 74.6651785714286, but the layoutExtent is 74.66517857142861.

Maybe you have fallen prey to floating point rounding errors, and should explicitly apply the min() or max() functions, or the clamp() method, to the layoutExtent?

The RenderSliver that returned the offending geometry was: RenderSliverPinnedPersistentHeader#942fa relayoutBoundary=up1 NEEDS-LAYOUT NEEDS-PAINT
...  needs compositing
...  parentData: paintOffset=Offset(0.0, 0.0) (can use size)
...  constraints: SliverConstraints(AxisDirection.down, GrowthDirection.forward, ScrollDirection.reverse, scrollOffset: 85.3, remainingPaintExtent: 547.4, crossAxisExtent: 411.4, crossAxisDirection: AxisDirection.right, viewportMainAxisExtent: 547.4, remainingCacheExtent: 882.8, cacheOrigin: -85.3)
...  geometry: SliverGeometry(scrollExtent: 160.0, paintExtent: 74.7, layoutExtent: 74.7, maxPaintExtent: 160.0, hasVisualOverflow: true, cacheExtent: 160.0)
...    scrollExtent: 160.0
...    paintExtent: 74.7
...    layoutExtent: 74.7
...    maxPaintExtent: 160.0
...    hasVisualOverflow: true
...    cacheExtent: 160.0
...  child position: 0.0
The relevant error-causing widget was: 
  SliverPinnedPersistentHeader SliverPinnedPersistentHeader```

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[zmtzawqlp]

It happens in demo on Flutter 3.0.0?

[per-johansson-74]

I looked more into it. I can not get this error using the example.

I get it when I use animated container in SliverPinnedPersistentHeaderDelegate using final progress = shrinkOffset / maxExtent; and padding: EdgeInsets.lerp( const EdgeInsets.symmetric(horizontal: 16, vertical: 16), const EdgeInsets.symmetric(horizontal: 4, vertical: 4), progress, ),

So I can solve it two ways, remove edgeinsets.lerp from the delegate or comment out layoutExtent: layoutExtent, from the library. I'll just remove the code from delegate that triggers the rounding error in the lib.

(I don't use this for pinning header, I set minExtentProtoType to 0, and maxExtentProtoType i use template so i get the dynamic height of maxExtent, then i put the actual drawn widget in the delegate)

I'll add that if I use same delegate directly in SliverPersistentHeaderDelegate there is no crash due to the floating point rounding.

[zmtzawqlp]

sounds great，it seems a special case with dynamic height，maybe we can make another widget for this case