Getting NullReferenceException in ToCss()

[ac-lap]

I use ExCSS library to parse the CSS file content, edit some of the properties and then generate the updated CSS string. The code is something like this -

var parser = new StylesheetParser();
var stylesheet = parser.Parse(cssInput);
// edit rules here
processedCss = stylesheet.ToCss();

But for lot of css strings, the parser works fine, but the .ToCSS() method throws null ref exception.
The simplest one being this -

@page {
    margin-bottom: 5pt;
    margin-top: 5pt
    }

I have attached other problematic css files.
Prob-CSS-2.txt
Prob-CSS-1.txt

[majora2007]

Just came to give the same report. I didn't get this exception in the previous version.

[majora2007]

@TylerBrinks any ideas on this regression?

[TylerBrinks]

The code shouldn't have change substantially - I'm investigating. I have a guess that it's an issue with parsing children of the @page directive.

[majora2007]

That's also what I'm thinking. I saw another issue that seems to have traced it down to that. I noticed @page as well in the css I was processing.

I had assumed anything that couldn't be processed would be dropped, but it could be some complex logic. Thanks for taking a look into this. My epub reader relies on this library for rendering.

[TylerBrinks]

Version 4.1.4 is available on NuGet.org

[majora2007]

Sorry to reopen, but this issue isn't fixed on v4.2.0 still. I have:

@page {
    margin-bottom: 5pt;
    margin-top: 5pt
    }

which still throws:

System.NullReferenceException: Object reference not set to an instance of an object.
   at ExCSS.PageRule.get_SelectorText()
   at ExCSS.PageRule.ToCss(TextWriter writer, IStyleFormatter formatter)
   at ExCSS.CompressedStyleFormatter.WriteJoined(StringBuilder sb, IEnumerable`1 elements, String separator, Boolean first)
   at ExCSS.CompressedStyleFormatter.ExCSS.IStyleFormatter.Sheet(IEnumerable`1 rules)
   at ExCSS.Stylesheet.ToCss(TextWriter writer, IStyleFormatter formatter)
   at ExCSS.FormatExtensions.ToCss(IStyleFormattable style, IStyleFormatter formatter)
   at ExCSS.FormatExtensions.ToCss(IStyleFormattable style)

when doing .ToCSS()

I can validate that a PageRule is created, but there are no margins.

Edit: This happens not only from css with Page, but you can see here a CSS which is throwing. This has made it so I can't upgrade from v4.1.0. But with the new contributors, I would really like to update to get the newest support.