HtmlDocument.ParseDocumentAsync results in ArgumentOutOfRangeException

Bug Report

Prerequisites

• Can you reproduce the problem in a MWE?
• Are you running the latest version of AngleSharp?
• Did you check the FAQs to see if that helps you?
• Are you reporting to the correct repository? (there are multiple AngleSharp libraries, e.g., AngleSharp.Css for CSS support)
• Did you perform a search in the issues? Yes, #452 But was nothing wrong.

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Description

Exception when parsing a ‘document’.

System.ArgumentOutOfRangeException
  HResult=0x80131502
  Message=Index must be within the bounds of the List. (Parameter 'index')
  Source=System.Private.CoreLib
  StackTrace:
   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at System.Collections.Generic.List`1.Insert(Int32 index, T item)
   at AngleSharp.Html.Parser.HtmlDomBuilder.HeisenbergAlgorithm(HtmlTagToken tag)
   at AngleSharp.Html.Parser.HtmlDomBuilder.InBodyEndTag(HtmlTagToken tag)
   at AngleSharp.Html.Parser.HtmlDomBuilder.InCell(HtmlToken token)
   at AngleSharp.Html.Parser.HtmlDomBuilder.<ParseAsync>d__23.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
   at AngleSharp.Html.Parser.HtmlParser.<ParseAsync>d__28.MoveNext()

Steps to Reproduce

await new HtmlParser().ParseDocumentAsync(await new HttpClient().GetStringAsync("http://www.artfiles.org/netlib.org/blast/blast-nearterm"));

Expected behavior:

That it handles the input without exception.

Actual behavior:

Something internally goes wrong.

Environment details:

.NET Core 3.1 on Windows 10 Pro 2004

Possible Solution

It looks like it must be something with list management. Hopefully it’s clear and quick to fix.

[KoalaBear84]

Thanks, ‘verified’! 👍

[FlorianRappl]

Fix available in the preview and in devel.