codesanitize

I do know the title isnt clear however what im basically attempting to do is do my very own rendering for an EPUB and im presently taking a naive strategy in the direction of paginating the chapter content material and attempting to render it in a WebView after splitting the content material primarily based on the tags.

My problem begins from the purpose the place i can’t appear to precisely cut up the content material to suit into the web page, and it overflows within the rendered internet view.

I’ve a separate internet view which renders off display screen and calculates the scrollHeight of the div the place the content material is being injected in.

The web page is principally constructed block by block (tag by tag) till the div begins to overflow and the peak of the div is bigger than the View that its rendered to.

The pagination perform yields the content material gathered simply earlier than the peak is exceeded.

The issue is that it by no means suits to display screen and there’s all the time a little bit of vertical overflow left.

My goal is to in the end generate an inventory of animated WebViews the consumer can scroll via horizontally like an precise web page flip of a e book.

I might actually admire some assist in figuring out the logic or calculation flaw right here within the format top comparisons. Let me know if ive missed one thing.

Under is the react native part which does the pagination and rendering

import { EPUBChapter, epubHtmlTemplate, ParsedEPUB } from "@/lib/EpubParser";
import { useEffect, useRef, useState } from "react";
import { parseDocument, DomUtils } from "htmlparser2";
import render from "dom-serializer";
import { WebView } from "react-native-webview";
import { Textual content } from "./ui/textual content";
import { useHtmlHeightMeasurer } from "@/hooks/useHtmlHeightMeasurer";
import { View, PixelRatio, FlatList } from "react-native";

export perform WebViewCarousel({
  parsedEpub,
  currentChapterIndex = 0,
}: {
  parsedEpub: ParsedEPUB;
  currentChapterIndex: quantity;
}) {
  const chapters = parsedEpub.chapters;
  const [currentChapter, setCurrentChapter] = useState(
    undefined
  );
  const view = useRef(null);
  // const { html } = useHtmlHeightMeasurer(viewDimensions.width, viewDimensions.top);
  const { measureHtmlHeight, MeasuringWebView, resizeWebView } =
    useHtmlHeightMeasurer(355, 355);
  const [pages, setPages] = useState([]);

  async perform* pageGenerator(
    chapterHtml: string,
    dimensions: { width: quantity; top: quantity }
  ) {
    resizeWebView({ top: dimensions.width, width: dimensions.top });
    const parsedChapterHtml = parseDocument(chapterHtml);
    const htmlNodes = parsedChapterHtml.kids;
    let pageNodes: typeof parsedChapterHtml.kids = [];
    const chapterContent = DomUtils.findOne(
      (elem) => elem.title === "part",
      htmlNodes
    );
    // const pixelHeight = PixelRatio.getPixelSizeForLayoutSize(dimensions.top);
    const pixelHeight = dimensions.top;


    if (chapterContent) {
      for (const [index, node] of chapterContent.kids.entries()) {
        const testPage = render([...pageNodes, node]);
        // console.log('Node: ' + render(node));
        if (testPage.trim()) {
          const webViewHeight = await measureHtmlHeight(
            epubHtmlTemplate(testPage)
          );
          console.log("View top: " + pixelHeight);
          console.log("Measured Peak: " + webViewHeight);
          if (webViewHeight >= pixelHeight) {
            console.log("Yielding Web page");
            
            yield pageNodes;
            pageNodes = [];
          }

          pageNodes.push(node);
        }
      }
    }

    console.log("Last web page");
    return pageNodes;
  }

  // const generatePage = pageGenerator(chapters[currentChapterIndex].content material);

  async perform generatePages({
    width,
    top,
  }: {
    width: quantity;
    top: quantity;
  }) {
    const pagesToAdd = [];

    for await (const web page of pageGenerator(
      chapters[currentChapterIndex].content material,
      { width, top }
    )) {
      console.log(render(web page));
      pagesToAdd.push(render(web page));
    }

    setPages([...pages, ...pagesToAdd]);
  }

  return (
     {
        generatePages({
          top: e.nativeEvent.format.top,
          width: e.nativeEvent.format.width,
        });
      }}
    >
      
      {pages.size > 0 && (
        
      )}
    
  );
}

The offscreen part used to measure the content material till it overflows

import { epubHtmlTemplate } from "@/lib/EpubParser";
import React, { useRef, useState } from "react";
import { View } from "react-native";
import { WebView } from "react-native-webview";

const measureJs = `
  (() => {
    const observer = new MutationObserver(measure)
    let debounce;
    
    perform measure() {
      clearTimeout(debounce);
      debounce = setTimeout(() => {
        strive {
          const container = doc.getElementById('epub-content');
          if(container) {
            const top = container.scrollHeight;
            window.ReactNativeWebView.postMessage(JSON.stringify({
              kind: 'measurement',
              worth: top
            }));
          } else {
            window.ReactNativeWebView.postMessage(JSON.stringify({
              kind: 'error',
              worth: 'Lacking container with id epub-content'
            }));
          }
        } catch (error) {
          window.ReactNativeWebView.postMessage(JSON.stringify({
            kind: 'error',
            worth: error.message
          }));
        }
      }, 150);
    }

    observer.observe(doc.physique, { 
      childList: true, 
      subtree: true,
      attributes: true
    });

    measure();
  })()
`;

export perform useHtmlHeightMeasurer(width: quantity, top: quantity) {
  const [html, setHtml] = useState("");
  const resolver = useRef<(h: quantity) => void>();
  const webViewRef = useRef(null);
  const [webViewDimensions, setWebViewDimensions] = useState({
    top: 0,
    width: 0
  });

  const measureHtmlHeight = (htmlString: string) =>
    new Promise((resolve) => {
      resolver.present = resolve;
      setHtml(htmlString);
    });
  
  const resizeWebView = ({ width, top }: { width: quantity, top: quantity }) => {
    setWebViewDimensions({ width, top })
  }

  const MeasuringWebView = () => (
    
       {
          const knowledge = JSON.parse(occasion.nativeEvent.knowledge);
          if(knowledge.kind === 'error') {
            console.error(knowledge.worth)
          }
          if (knowledge.kind === "measurement") {
            const h = Quantity(knowledge.worth);
            if (resolver.present) {
              resolver.present(h);
              resolver.present = undefined;
            }
          }
        }}
        fashion={{ width: webViewDimensions.width, top: webViewDimensions.top, backgroundColor: "clear" }}
      />
    
  );

  return { measureHtmlHeight, MeasuringWebView, resizeWebView };
}

Whereas testing on simulators, I’ve hit a problem the place ViewThatFits seems to have a threading challenge. This will trigger warnings or a crash.

The surroundings is the next:

• Xcode 26.0 beta 5
• Swift 6 with strict concurrency checking
• minimal deployment goal iOS 17.0
• debug construct configuration
• iPhone 16 simulator operating iOS 18.5 (causes crash)
• iPhone 15 simulator operating iOS 17.5 (causes warnings)

The next code can be utilized to breed the issue when operating with the next textual content dimension:

struct ContentView: View {
    let item1 = "The fast brown fox jumps over the lazy canine."
    let item2 = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."
    @State non-public var isExpanded = false

    enum LayoutHint {
        case regular
        case spaceIsTight
        case scrolling
    }

    non-public func itemList(gadgets: [String], trace: LayoutHint) -> some View {
        VStack(alignment: .main, spacing: 9) {
            ForEach(Array(gadgets.enumerated()), id: .offset) { _, textual content in
                Textual content(textual content)
                    .font(.footnote)
            }
        }
        .body(maxWidth: .infinity, alignment: .main)
        .fixedSize(horizontal: false, vertical: true)
    }

    non-public func expandedExplanation(gadgets: [String]) -> some View {
        ViewThatFits(in: .vertical) {

            // If any of those 3 views are commented out, it really works
            itemList(gadgets: gadgets, trace: .regular)
            itemList(gadgets: gadgets, trace: .spaceIsTight)
            ScrollView {
                itemList(gadgets: gadgets, trace: .scrolling)
            }
        }
    }

    non-public var chevronUp: some View {
        Picture(systemName: "chevron.compact.up")
            .imageScale(.medium)
            .font(.title)
            .fontWeight(.semibold)
            .foregroundStyle(.grey)

            // If vertical padding is added, it really works
            // .padding(.vertical, 10)
            .body(maxWidth: .infinity)
    }

    non-public var expandedContent: some View {
        VStack(alignment: .main, spacing: 20) {
            expandedExplanation(gadgets: [item1, item2])

            // If chevronUp is commented out, it really works
            chevronUp
        }
        .padding()
    }

    non-public var collapsedContent: some View {
        Textual content("Present expanded")
            .foregroundStyle(Shade(.hyperlink))
            .padding()
            .body(maxWidth: .infinity)
    }

    var physique: some View {
        ZStack(alignment: .high) {
            if isExpanded {
                expandedContent
            } else {
                collapsedContent
            }
        }
        .clipped()
        .contentShape(.rect)
        .background {
            UnevenRoundedRectangle(
                topLeadingRadius: 0,
                bottomLeadingRadius: 20,
                bottomTrailingRadius: 20,
                topTrailingRadius: 0
            )
            .fill(Shade(.systemGray6))
            .ignoresSafeArea(edges: .high)
        }
        .onTapGesture {
            withAnimation(.easeInOut(period: 0.25)) {
                isExpanded.toggle()
            }
        }
        .body(maxHeight: .infinity, alignment: .high)
    }
}

Right here is the way it ought to look when the highest part is expanded (notice the textual content dimension):

The crash that occurs when operating on the iPhone 16 simulator with iOS 18.5 is as follows:

#0  0x0000000102506e28 in _dispatch_assert_queue_fail ()
#1  0x000000010253c388 in dispatch_assert_queue$V2.chilly.1 ()
#2  0x0000000102506db0 in dispatch_assert_queue ()
#3  0x0000000249df246c in swift_task_isCurrentExecutorWithFlagsImpl ()
#4  0x0000000102e80504 in closure #1 in closure #1 in ContentView.itemList(gadgets:trace:) ()
#5  0x0000000102e807d4 in thunk for @escaping @callee_guaranteed (@unowned Int, @assured String) -> (@owned Textual content) ()
#6  0x00000001d4c8cd24 in closure #1 () -> τ_0_2 in SwiftUI.ForEachState.merchandise(at: τ_0_0.Index, offset: Swift.Int) -> SwiftUI.ForEachState.Merchandise ()
#7  0x00000001d4c94dac in partial apply forwarder for closure #1 () -> τ_0_2 in SwiftUI.ForEachState.merchandise(at: τ_0_0.Index, offset: Swift.Int) -> SwiftUI.ForEachState.Merchandise ()
#8  0x00000001d4a7004c in closure #1 (Swift.UnsafeMutablePointer>) throws -> τ_0_0 in SwiftUI._withObservation(do: () throws -> τ_0_0) throws -> (worth: τ_0_0, accessList: Swift.Optionally available) ()
#9  0x00000001d473a6d8 in partial apply forwarder for closure #1 (Swift.UnsafeMutablePointer>) throws -> τ_0_0 in SwiftUI._withObservation(do: () throws -> τ_0_0) throws -> (worth: τ_0_0, accessList: Swift.Optionally available) ()
#10 0x00000001d48c9288 in withUnsafePointer ()
#11 0x00000001d4c8c160 in merchandise ()
#12 0x00000001d4c8e24c in forEachItem ()
#13 0x00000001d4c94b38 in perform signature specialization  of SwiftUI.ForEachList.applyNodes(from: inout Swift.Int, model: SwiftUI._ViewList_IteratorStyle, checklist: Swift.Optionally available>, rework: inout SwiftUI._ViewList_SublistTransform, to: (inout Swift.Int, SwiftUI._ViewList_IteratorStyle, SwiftUI._ViewList_Node, inout SwiftUI._ViewList_SublistTransform) -> Swift.Bool) -> Swift.Bool ()
#14 0x00000001d4c92ec8 in protocol witness for SwiftUI.ViewList.applyNodes(from: inout Swift.Int, model: SwiftUI._ViewList_IteratorStyle, checklist: Swift.Optionally available>, rework: inout SwiftUI._ViewList_SublistTransform, to: (inout Swift.Int, SwiftUI._ViewList_IteratorStyle, SwiftUI._ViewList_Node, inout SwiftUI._ViewList_SublistTransform) -> Swift.Bool) -> Swift.Bool in conformance SwiftUI.ForEachList : SwiftUI.ViewList in SwiftUI ()
#15 0x00000001d49a8374 in applySublists ()
#16 0x00000001d49a501c in applySublists ()
#17 0x00000001d460d09c in generic specialization  of SwiftUI.DynamicContainerInfo.updateItems(disableTransitions: Swift.Bool) -> (modified: Swift.Bool, hasDepth: Swift.Bool) ()
#18 0x00000001d460c258 in generic specialization  of SwiftUI.DynamicContainerInfo.updateValue() -> () ()
#19 0x00000001d462b764 in generic specialization > of implicit closure #1 (Swift.UnsafeMutableRawPointer, __C.AGAttribute) -> () in closure #1 () -> (Swift.UnsafeMutableRawPointer, __C.AGAttribute) -> () in closure #1 (Swift.UnsafePointer) -> AttributeGraph.Attribute in AttributeGraph.Attribute.init(τ_1_0) -> AttributeGraph.Attribute ()
#20 0x00000001c00ca438 in AG::Graph::UpdateStack::replace ()
#21 0x00000001c00cac04 in AG::Graph::update_attribute ()
#22 0x00000001c00d24dc in AG::Graph::input_value_ref_slow ()
#23 0x00000001c00e8054 in AGGraphGetValue ()
#24 0x00000001d496010c in SwiftUI.DynamicLayoutComputer.containerInfo.getter : Swift.Optionally available ()
#25 0x00000001d4960248 in updateValue ()
#26 0x00000001d4947d58 in partial apply forwarder for implicit closure #1 (Swift.UnsafeMutableRawPointer, __C.AGAttribute) -> () in closure #1 () -> (Swift.UnsafeMutableRawPointer, __C.AGAttribute) -> () in closure #1 (Swift.UnsafePointer) -> AttributeGraph.Attribute in AttributeGraph.Attribute.init(τ_1_0) -> AttributeGraph.Attribute ()
#27 0x00000001c00ca438 in AG::Graph::UpdateStack::replace ()
#28 0x00000001c00cac04 in AG::Graph::update_attribute ()
#29 0x00000001c00d22f0 in AG::Graph::input_value_ref_slow ()
#30 0x00000001c00e7e14 in AGGraphGetInputValue ()
#31 0x00000001d47d1904 in dimension ()
#32 0x00000001d4aab49c in sizeThatFits ()
#33 0x00000001d4aabe74 in protocol witness for SwiftUI.UnaryLayout.sizeThatFits(in: SwiftUI._ProposedSize, context: SwiftUI.SizeAndSpacingContext, little one: SwiftUI.LayoutProxy) -> __C.CGSize in conformance SwiftUI._FlexFrameLayout : SwiftUI.UnaryLayout in SwiftUI ()
#34 0x00000001d4934fcc in merged SwiftUI.UnaryLayoutEngine.sizeThatFits(SwiftUI._ProposedSize) -> __C.CGSize ()
#35 0x00000001d4934cf4 in protocol witness for SwiftUI.LayoutEngine.sizeThatFits(SwiftUI._ProposedSize) -> __C.CGSize in conformance SwiftUI.UnaryLayoutEngine : SwiftUI.LayoutEngine in SwiftUI ()
#36 0x00000001d4b700ac in sizeThatFits ()
#37 0x00000001d47d1970 in dimension ()
#38 0x00000001d4664b3c in protocol witness for SwiftUI.UnaryLayout.sizeThatFits(in: SwiftUI._ProposedSize, context: SwiftUI.SizeAndSpacingContext, little one: SwiftUI.LayoutProxy) -> __C.CGSize in conformance SwiftUI._FixedSizeLayout : SwiftUI.UnaryLayout in SwiftUI ()
#39 0x00000001d4934fcc in merged SwiftUI.UnaryLayoutEngine.sizeThatFits(SwiftUI._ProposedSize) -> __C.CGSize ()
#40 0x00000001d4934cf4 in protocol witness for SwiftUI.LayoutEngine.sizeThatFits(SwiftUI._ProposedSize) -> __C.CGSize in conformance SwiftUI.UnaryLayoutEngine : SwiftUI.LayoutEngine in SwiftUI ()
#41 0x00000001d4b700ac in sizeThatFits ()
#42 0x00000001d4b6ee60 in sizeThatFits ()
#43 0x00000001d3b4e35c in closure #1 (SwiftUI._ViewOutputs, Swift.Bool) -> Swift.Bool in closure #1 () -> () in SwiftUI.SizeFittingLayoutComputer.Engine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available ()
#44 0x00000001d3b4cfec in closure #1 (SwiftUI._ViewList_Sublist) -> Swift.Bool in SwiftUI.SizeFittingState.applyChildren(selectLast: Swift.Bool, to: (SwiftUI._ViewOutputs, Swift.Bool) -> Swift.Bool) -> () ()
#45 0x00000001d49a7640 in applySublists ()
#46 0x00000001d49b09e8 in merged partial apply forwarder for closure #1 (inout Swift.Int, SwiftUI._ViewList_IteratorStyle, SwiftUI._ViewList_Node, inout SwiftUI._ViewList_SublistTransform) -> Swift.Bool in SwiftUI._ViewList_Node.applySublists(from: inout Swift.Int, model: SwiftUI._ViewList_IteratorStyle, rework: inout SwiftUI._ViewList_SublistTransform, to: (SwiftUI._ViewList_Sublist) -> Swift.Bool) -> Swift.Bool ()
#47 0x00000001d49abddc in applyNodes ()
#48 0x00000001d49a8374 in applySublists ()
#49 0x00000001d49a501c in applySublists ()
#50 0x00000001d3b4c190 in applyChildren ()
#51 0x00000001d3b4e144 in closure #1 () -> () in SwiftUI.SizeFittingLayoutComputer.Engine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available ()
#52 0x00000001c00cafb0 in AG::Graph::with_update ()
#53 0x00000001d3b4e524 in protocol witness for SwiftUI.LayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available in conformance SwiftUI.SizeFittingLayoutComputer.Engine : SwiftUI.LayoutEngine in SwiftUI ()
#54 0x00000001d4b70194 in explicitAlignment ()
#55 0x00000001d4c16cfc in perform signature specialization  Swift.Optionally available in SwiftUI.StackLayout.(UnmanagedImplementation in _00690F480F8D293143B214DBE6D72CD0).placeChildren(in: SwiftUI.ProposedViewSize) -> (), Argument Varieties : [Swift.Optional]> of SwiftUI.StackLayout.UnmanagedImplementation.sizeChildrenGenerallyWithConcreteMajorProposal(in: SwiftUI.ProposedViewSize, minorProposalForChild: (SwiftUI.StackLayout.Little one) -> Swift.Optionally available) -> () ()
#56 0x00000001d4c1779c in perform signature specialization  Swift.Optionally available in SwiftUI.StackLayout.(UnmanagedImplementation in _00690F480F8D293143B214DBE6D72CD0).placeChildren(in: SwiftUI.ProposedViewSize) -> (), Argument Varieties : [Swift.Optional]> of SwiftUI.StackLayout.UnmanagedImplementation.placeChildren1(in: SwiftUI.ProposedViewSize, minorProposalForChild: (SwiftUI.StackLayout.Little one) -> Swift.Optionally available) -> () ()
#57 0x00000001d4c15fb4 in placeChildren ()
#58 0x00000001d4c15c84 in explicitAlignment ()
#59 0x00000001d4c14664 in explicitAlignment ()
#60 0x00000001d47a46a8 in merged protocol witness for SwiftUI.Format.explicitAlignment(of: SwiftUI.HorizontalAlignment, in: __C.CGRect, proposal: SwiftUI.ProposedViewSize, subviews: SwiftUI.LayoutSubviews, cache: inout τ_0_0.Cache) -> Swift.Optionally available in conformance SwiftUI._VStackLayout : SwiftUI.Format in SwiftUI ()
#61 0x00000001d496875c in closure #1 (Swift.UnsafeMutablePointer) -> Swift.Optionally available in closure #1 (Swift.UnsafeMutablePointer>) -> Swift.Optionally available in SwiftUI.ViewLayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available ()
#62 0x00000001d49684c4 in closure #1 (Swift.UnsafeMutablePointer>) -> Swift.Optionally available in SwiftUI.ViewLayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available ()
#63 0x00000001d496ab24 in partial apply forwarder for closure #1 (Swift.UnsafeMutablePointer>) -> Swift.Optionally available in SwiftUI.ViewLayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available ()
#64 0x00000001d48c9288 in withUnsafePointer ()
#65 0x00000001d496837c in explicitAlignment ()
#66 0x00000001d4968df0 in protocol witness for SwiftUI.LayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available in conformance SwiftUI.ViewLayoutEngine : SwiftUI.LayoutEngine in SwiftUI ()
#67 0x00000001d4b70194 in explicitAlignment ()
#68 0x00000001d47d26f0 in explicitAlignment ()
#69 0x00000001d4934c68 in explicitAlignment ()
#70 0x00000001d4934d08 in protocol witness for SwiftUI.LayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available in conformance SwiftUI.UnaryLayoutEngine : SwiftUI.LayoutEngine in SwiftUI ()
#71 0x00000001d4b70194 in explicitAlignment ()
#72 0x00000001d4663040 in SwiftUI.ViewDimensions.subscript.getter : (SwiftUI.AlignmentKey) -> CoreGraphics.CGFloat ()
#73 0x00000001d4569c74 in perform signature specialization  __C.CGPoint in SwiftUI._ZStackLayout.placeSubviews(in: __C.CGRect, proposal: SwiftUI.ProposedViewSize, subviews: SwiftUI.LayoutSubviews, cache: inout ()) -> (), Argument Varieties : [SwiftUI._ZStackLayout]> of generic specialization , SwiftUI.ViewDimensions>, __C.CGPoint> of Swift.Sequence.cut back(τ_1_0, (τ_1_0, τ_0_0.Aspect) throws -> τ_1_0) throws -> τ_1_0 ()
#74 0x00000001d458d844 in perform signature specialization  of SwiftUI._ZStackLayout.placeSubviews(in: __C.CGRect, proposal: SwiftUI.ProposedViewSize, subviews: SwiftUI.LayoutSubviews, cache: inout ()) -> () ()
#75 0x00000001d4967e0c in closure #1 (Swift.UnsafeMutablePointer) -> () in SwiftUI.ViewLayoutEngine.childGeometries(at: SwiftUI.ViewSize, origin: __C.CGPoint) -> Swift.Array ()
#76 0x00000001d4967bb8 in childGeometries ()
#77 0x00000001d4968aa4 in static SwiftUI.ViewLayoutEngine.defaultAlignment(_: SwiftUI.AlignmentKey, dimension: SwiftUI.ViewSize, information: Swift.UnsafeMutableRawPointer) -> Swift.Optionally available ()
#78 0x00000001d4968e10 in protocol witness for static SwiftUI.DefaultAlignmentFunction.defaultAlignment(_: SwiftUI.AlignmentKey, dimension: SwiftUI.ViewSize, information: Swift.UnsafeMutableRawPointer) -> Swift.Optionally available in conformance SwiftUI.ViewLayoutEngine : SwiftUI.DefaultAlignmentFunction in SwiftUI ()
#79 0x00000001d495287c in merged protocol witness for SwiftUI.Format.explicitAlignment(of: SwiftUI.HorizontalAlignment, in: __C.CGRect, proposal: SwiftUI.ProposedViewSize, subviews: SwiftUI.LayoutSubviews, cache: inout τ_0_0.Cache) -> Swift.Optionally available in conformance SwiftUI._ZStackLayout : SwiftUI.Format in SwiftUI ()
#80 0x00000001d496875c in closure #1 (Swift.UnsafeMutablePointer) -> Swift.Optionally available in closure #1 (Swift.UnsafeMutablePointer>) -> Swift.Optionally available in SwiftUI.ViewLayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available ()
#81 0x00000001d49684c4 in closure #1 (Swift.UnsafeMutablePointer>) -> Swift.Optionally available in SwiftUI.ViewLayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available ()
#82 0x00000001d496ab24 in partial apply forwarder for closure #1 (Swift.UnsafeMutablePointer>) -> Swift.Optionally available in SwiftUI.ViewLayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available ()
#83 0x00000001d48c9288 in withUnsafePointer ()
#84 0x00000001d496837c in explicitAlignment ()
#85 0x00000001d4968df0 in protocol witness for SwiftUI.LayoutEngine.explicitAlignment(_: SwiftUI.AlignmentKey, at: SwiftUI.ViewSize) -> Swift.Optionally available in conformance SwiftUI.ViewLayoutEngine : SwiftUI.LayoutEngine in SwiftUI ()
#86 0x00000001d4b70194 in explicitAlignment ()
#87 0x00000001d4663040 in SwiftUI.ViewDimensions.subscript.getter : (SwiftUI.AlignmentKey) -> CoreGraphics.CGFloat ()
#88 0x00000001d4aaa9f0 in generic specialization  of SwiftUI.FrameLayoutCommon.commonPlacement(of: SwiftUI.LayoutProxy, in: SwiftUI.PlacementContext, childProposal: SwiftUI._ProposedSize) -> SwiftUI._Placement ()
#89 0x00000001d49336cc in generic specialization  of SwiftUI.UnaryLayoutEngine.childPlacement(at: SwiftUI.ViewSize) -> SwiftUI._Placement ()
#90 0x00000001d4947910 in partial apply forwarder for generic specialization  of closure #1 (inout SwiftUI.UnaryLayoutEngine) -> SwiftUI._Placement in SwiftUI.UnaryChildGeometry.worth.getter : SwiftUI.ViewGeometry ()
#91 0x00000001d48c33f0 in partial apply forwarder for generic specialization , SwiftUI._Placement> of closure #1 (inout τ_0_0) -> τ_0_1 in SwiftUI.LayoutComputer.withMutableEngine(kind: τ_0_0.Kind, do: (inout τ_0_0) -> τ_0_1) -> τ_0_1 ()
#92 0x00000001d4b70d10 in partial apply forwarder for closure #1 (Swift.UnsafeMutablePointer) -> τ_1_1 in SwiftUI.LayoutEngineBox.mutateEngine(as: τ_1_0.Kind, do: (inout τ_1_0) -> τ_1_1) -> τ_1_1 ()
#93 0x00000001d48c9288 in withUnsafePointer ()
#94 0x00000001d4b6fe08 in mutateEngine ()
#95 0x00000001d49318d4 in generic specialization  of SwiftUI.UnaryChildGeometry.worth.getter : SwiftUI.ViewGeometry ()
#96 0x00000001d49413a4 in merged generic specialization > of implicit closure #1 (Swift.UnsafeMutableRawPointer, __C.AGAttribute) -> () in closure #1 () -> (Swift.UnsafeMutableRawPointer, __C.AGAttribute) -> () in closure #1 (Swift.UnsafePointer) -> AttributeGraph.Attribute in AttributeGraph.Attribute.init(τ_1_0) -> AttributeGraph.Attribute ()
#97 0x00000001c00ca438 in AG::Graph::UpdateStack::replace ()
#98 0x00000001c00cac04 in AG::Graph::update_attribute ()
#99 0x00000001c00d80b4 in AG::Subgraph::replace ()
#100    0x00000001d4d6f118 in SwiftUI.ViewGraph.updateOutputs(async: Swift.Bool) -> () ()
#101    0x00000001d4d6f618 in closure #2 () -> () in SwiftUI.ViewGraph.updateOutputsAsync(at: SwiftUI.Time) -> Swift.Optionally available ()
#102    0x00000001c00e70f8 in AGGraphWithMainThreadHandler ()
#103    0x00000001d4d69a90 in updateOutputsAsync ()
#104    0x00000001d4d643c4 in renderAsync ()
#105    0x00000001d3b436d4 in displayLinkTimer ()
#106    0x00000001d3b43eb4 in SwiftUI.DisplayLink.displayLinkTimer(__C.CADisplayLink) -> () ()
#107    0x00000001d3b444c0 in @objc SwiftUI.DisplayLink.displayLinkTimer(__C.CADisplayLink) -> () ()
#108    0x000000018b3e2e44 in CA::Show::DisplayLinkItem::dispatch_ ()
#109    0x000000018b3def44 in CA::Show::DisplayLink::dispatch_items ()
#110    0x000000018b4e7a40 in display_timer_callback ()
#111    0x00000001803ed914 in __CFMachPortPerform ()
#112    0x0000000180429a6c in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ ()
#113    0x0000000180429084 in __CFRunLoopDoSource1 ()
#114    0x000000018042397c in __CFRunLoopRun ()
#115    0x0000000180422cec in CFRunLoopRunSpecific ()
#116    0x0000000180f0e38c in -[NSRunLoop(NSRunLoop) runMode:beforeDate:] ()
#117    0x0000000180f0e55c in -[NSRunLoop(NSRunLoop) run] ()
#118    0x00000001d3b45830 in perform signature specialization  of static SwiftUI.DisplayLink.asyncThread(arg: Swift.Optionally available) -> () ()
#119    0x00000001d3b44520 in @objc static SwiftUI.DisplayLink.asyncThread(arg: Swift.Optionally available) -> () ()
#120    0x0000000180f35148 in __NSThread__start__ ()
#121    0x0000000102cee5f0 in _pthread_start ()

The warning that’s seen when operating on the iPhone 15 simulator with iOS 17.5 is as follows:

warning: information race detected: @MainActor perform at StackOverflow/ContentView.swift:52 was not referred to as on the principle thread

Line 52 is the ForEach contained in the perform itemList.

It appears to me that this have to be a SwiftUI bug, particularly since it is just underneath sure circumstances. For instance, the problem will not be seen when any of the next modifications are made:

• a distinct textual content dimension is used
• the second textual content merchandise is shorter (1 line as a substitute of three)
• any 1 of the three views inside ViewthatFits is commented out
• vertical padding is added to the chevron
• the chevron is faraway from view.

These modifications should not fixing the issue, they’re simply stopping it from occurring for the setup described. So I would like a extra dependable repair. Specifically, I’m questioning if there could be a method to stop the issue with some sort of annotation or actor directive within the code?

How can the code be fastened in order that the problems should not seen when operating as described?