Index was outside the bounds of the array

Suddenly getting this a lot

    at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
    at AngleSharp.Dom.Element.GetOrCreateCallback(Type type)
    at AngleSharp.Dom.Element.RegisterCallback[TElement](String name, Action`2 callback)
    at AngleSharp.Dom.Html.HtmlStyleElement..cctor()

We’ve also seen it in conjunction with a call from HtmlSanitiser

  at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at AngleSharp.Dom.Element.GetOrCreateCallback(Type type)
   at AngleSharp.Dom.Element.AttributeChanged(String localName, String namespaceUri, String oldValue, String newValue)
   at AngleSharp.Dom.Collections.NamedNodeMap.SetNamedItemWithNamespaceUri(IAttr item, Boolean suppressMutationObservers)
   at Ganss.XSS.HtmlSanitizer.DoSanitize(IHtmlDocument dom, IElement context, String baseUrl)
   at Ganss.XSS.HtmlSanitizer.Sanitize(String html, String baseUrl, IMarkupFormatter outputFormatter)

and

   at AngleSharp.Services.Default.HtmlElementFactory.<>c.<.ctor>b__3_39(Document document, String prefix)
   at AngleSharp.Services.Default.HtmlElementFactory.Create(Document document, String localName, String prefix)
   at AngleSharp.Parser.Html.HtmlDomBuilder.AddElement(HtmlTagToken tag, Boolean acknowledgeSelfClosing)
   at AngleSharp.Parser.Html.HtmlDomBuilder.InRow(HtmlToken token)
   at AngleSharp.Parser.Html.HtmlDomBuilder.Parse(HtmlParserOptions options)
   at AngleSharp.Parser.Html.HtmlDomBuilder.ParseFragment(HtmlParserOptions options, Element context)
   at AngleSharp.Dom.DocumentFragment..ctor(Element context, String html)
   at AngleSharp.Dom.Element.set_InnerHtml(String value)

Unfortunately I’ve been unable to replicate it in the debugger: the error is only in our logs (but we have hundreds of them)

[FlorianRappl]

Yes, that is true - once the dictionary is broken it is dead. Also I did not say I won’t fix it - just that the proposed fix won’t work and will not be implemented. I think the dictionary will be rather removed with v0.10 - there will be another (potentially a little bit less performing, but more flexible) way that also does not rely on a static component.

[FlorianRappl]

It’s not that simple, unfortunately. Yes, potentially it is little effort, but right now I cannot spend minutes to hours figuring out what changes are needed. That blocked another PR already and it will for sure prevent a new build on v0.9.9. Hence the build for AppVeyor still needs to be fixed before releasing it.

Maybe someone knows the answer already and can contribute.