Fixed issue with potential null-selector #52

FlorianRappl · FlorianRappl · commit 3000d9c47f1b · 2020-04-04T14:34:45.000+02:00
diff --git a/src/AngleSharp.Css.Tests/Extensions/AnalysisWindow.cs b/src/AngleSharp.Css.Tests/Extensions/AnalysisWindow.cs
@@ -4,6 +4,7 @@ namespace AngleSharp.Css.Tests.Extensions
     using AngleSharp.Dom;
     using NUnit.Framework;
     using System.Text;
+    using System.Threading.Tasks;
     using static CssConstructionFunctions;
 
     [TestFixture]
@@ -277,5 +278,16 @@ public void GetCascadedValueOfTextTransformFromElementStyle()
             Assert.IsNotNull(styleNormal);
             Assert.AreEqual("uppercase", styleNormal.GetTextTransform());
         }
+
+        [Test]
+        public async Task NullSelectorStillWorks_Issue52()
+        {
+            var sheet = ParseStyleSheet("a {}");
+            var document = await sheet.Context.OpenAsync(res => res.Content("<body></body>"));
+            sheet.Add(new CssStyleRule(sheet));
+            var sc = new StyleCollection(new[] { sheet }, new DefaultRenderDevice());
+            var decl = sc.ComputeCascadedStyle(document.Body);
+            Assert.IsNotNull(decl);
+        }
     }
 }
diff --git a/src/AngleSharp.Css/Dom/StyleCollectionExtensions.cs b/src/AngleSharp.Css/Dom/StyleCollectionExtensions.cs
@@ -103,7 +103,7 @@ public static ICssStyleDeclaration ComputeCascadedStyle(this StyleCollection sty
         #region Helpers
 
         private static IEnumerable<ICssStyleRule> SortBySpecificity(this IEnumerable<ICssStyleRule> rules, IElement element) =>
-            rules.Where(m => m.Selector.Match(element)).OrderBy(m => m.Selector.Specificity);
+            rules.Where(m => m.Selector?.Match(element) ?? false).OrderBy(m => m.Selector.Specificity);
 
         #endregion
     }

Original file line number	Diff line number	Diff line change
`@@ -103,7 +103,7 @@ public static ICssStyleDeclaration ComputeCascadedStyle(this StyleCollection sty`
`103`	`103`	`#region Helpers`
`104`	`104`
`105`	`105`	`private static IEnumerable<ICssStyleRule> SortBySpecificity(this IEnumerable<ICssStyleRule> rules, IElement element) =>`
`106`		`- rules.Where(m => m.Selector.Match(element)).OrderBy(m => m.Selector.Specificity);`
	`106`	`+ rules.Where(m => m.Selector?.Match(element) ?? false).OrderBy(m => m.Selector.Specificity);`
`107`	`107`
`108`	`108`	`#endregion`
`109`	`109`	`}`