From 0751cbed9da28f97ca52edd33daa3953aedced27 Mon Sep 17 00:00:00 2001
From: Florian Rappl <florian.rappl@smapiot.com>
Date: Thu, 2 Jun 2022 00:39:17 +0200
Subject: [PATCH] Fixed shorthand properties using inherit #100

---
 CHANGELOG.md                                  |  1 +
 .../Library/StringRepresentation.cs           | 32 +++++++++++++++++++
 .../Declarations/MarginDeclaration.cs         |  2 +-
 .../Declarations/PaddingDeclaration.cs        |  2 +-
 .../Extensions/ValueConverterExtensions.cs    |  3 +-
 5 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 797b5bb5..e9d7f38b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ Released on Tuesday, May 31 2022.
 - Dropped .NET Framework 4.6
 - Updated to use AngleSharp 0.17
 - Fixed casing issue with color, timing, and gradient functions (#109)
+- Fixed shorthand properties using `inherit` being omitted (#100)
 
 # 0.16.4
 
diff --git a/src/AngleSharp.Css.Tests/Library/StringRepresentation.cs b/src/AngleSharp.Css.Tests/Library/StringRepresentation.cs
index e6a8629e..70b421c0 100644
--- a/src/AngleSharp.Css.Tests/Library/StringRepresentation.cs
+++ b/src/AngleSharp.Css.Tests/Library/StringRepresentation.cs
@@ -1,9 +1,11 @@
 namespace AngleSharp.Css.Tests.Library
 {
+    using AngleSharp.Css.Dom;
     using AngleSharp.Css.Parser;
     using AngleSharp.Css.Values;
     using NUnit.Framework;
     using System.IO;
+    using static CssConstructionFunctions;
 
     [TestFixture]
     public class StringRepresentationTests
@@ -41,5 +43,35 @@ public void TransparentColorDoesNotWorkWithHexOutput_Issue96()
             Color.UseHex = false;
             Assert.AreEqual("rgba(65, 12, 48, 0.04)", text);
         }
+
+        [Test]
+        public void ShorthandPaddingInheritPropertiesShouldBeIncluded_Issue100()
+        {
+            var html = @"<style>#x div { padding: inherit }</style>";
+            var dom = ParseDocument(html);
+            var styleSheet = dom.StyleSheets[0] as ICssStyleSheet;
+            var css = styleSheet.ToCss();
+            Assert.AreEqual("#x div { padding: inherit }", css);
+        }
+
+        [Test]
+        public void ShorthandMarginInheritPropertiesShouldBeIncluded_Issue100()
+        {
+            var html = @"<style>#x div { margin: inherit }</style>";
+            var dom = ParseDocument(html);
+            var styleSheet = dom.StyleSheets[0] as ICssStyleSheet;
+            var css = styleSheet.ToCss();
+            Assert.AreEqual("#x div { margin: inherit }", css);
+        }
+
+        [Test]
+        public void ShorthandBorderInheritPropertiesShouldBeIncluded_Issue100()
+        {
+            var html = @"<style>#x div { border: inherit }</style>";
+            var dom = ParseDocument(html);
+            var styleSheet = dom.StyleSheets[0] as ICssStyleSheet;
+            var css = styleSheet.ToCss();
+            Assert.AreEqual("#x div { border: inherit }", css);
+        }
     }
 }
diff --git a/src/AngleSharp.Css/Declarations/MarginDeclaration.cs b/src/AngleSharp.Css/Declarations/MarginDeclaration.cs
index d7062e04..dd0d9fca 100644
--- a/src/AngleSharp.Css/Declarations/MarginDeclaration.cs
+++ b/src/AngleSharp.Css/Declarations/MarginDeclaration.cs
@@ -27,7 +27,7 @@ static class MarginDeclaration
 
         sealed class MarginAggregator : IValueAggregator, IValueConverter
         {
-            private static readonly IValueConverter converter = AutoLengthOrPercentConverter.Periodic();
+            private static readonly IValueConverter converter = Or(AutoLengthOrPercentConverter, AssignInitial(Length.Zero)).Periodic();
 
             public ICssValue Convert(StringSource source) => converter.Convert(source);
 
diff --git a/src/AngleSharp.Css/Declarations/PaddingDeclaration.cs b/src/AngleSharp.Css/Declarations/PaddingDeclaration.cs
index 20d08b4d..6f846a3c 100644
--- a/src/AngleSharp.Css/Declarations/PaddingDeclaration.cs
+++ b/src/AngleSharp.Css/Declarations/PaddingDeclaration.cs
@@ -27,7 +27,7 @@ static class PaddingDeclaration
 
         sealed class PaddingAggregator : IValueAggregator, IValueConverter
         {
-            private static readonly IValueConverter converter = LengthOrPercentConverter.Periodic();
+            private static readonly IValueConverter converter = Or(LengthOrPercentConverter, AssignInitial(Length.Zero)).Periodic();
 
             public ICssValue Convert(StringSource source) => converter.Convert(source);
 
diff --git a/src/AngleSharp.Css/Extensions/ValueConverterExtensions.cs b/src/AngleSharp.Css/Extensions/ValueConverterExtensions.cs
index ba84dbfc..17b59636 100644
--- a/src/AngleSharp.Css/Extensions/ValueConverterExtensions.cs
+++ b/src/AngleSharp.Css/Extensions/ValueConverterExtensions.cs
@@ -5,6 +5,7 @@ namespace AngleSharp.Css.Converters
     using AngleSharp.Text;
     using System;
     using System.Collections.Generic;
+    using static ValueConverters;
 
     /// <summary>
     /// Essential extensions for using the value converters.
@@ -61,7 +62,7 @@ public static IValueConverter Exclusive(this IValueConverter converter)
         }
 
         public static IValueConverter Option(this IValueConverter converter, ICssValue defaultValue) =>
-            new OptionValueConverter(converter, defaultValue);
+            Or(new OptionValueConverter(converter, defaultValue), AssignInitial(defaultValue));
 
         public static String Join<T>(this IEnumerable<T> values, String separator)
             where T : ICssValue