fix: filterconfig exclude rule is not works as documented

src/Docfx.Dotnet/Filters/ConfigFilterRuleItemUnion.cs

@@ -52,6 +52,10 @@ public ConfigFilterRuleItem Rule
             {
                 return Include;
             }
+
+            // If kind is not specified for exclude. Set `ExtendedSymbolKind.Type` as default kind.
+            Exclude.Kind ??= ExtendedSymbolKind.Type | ExtendedSymbolKind.Member;
+
             return Exclude;
         }
     }

src/Docfx.Dotnet/Filters/ExtendedSymbolKind.cs

@@ -3,23 +3,30 @@
 
 namespace Docfx.Dotnet;
 
+[Flags]
 internal enum ExtendedSymbolKind
 {
-    Assembly = 0x100,
-    Namespace = 0x110,
-    Type = 0x120,
-    Class,
-    Struct,
-    Enum,
-    Interface,
-    Delegate,
-    Member = 0x200,
-    Event,
-    Field,
-    Method,
-    Property,
+#pragma warning disable format
+    Assembly  = 1 << 1,
+    Namespace = 1 << 2,
+    // Type
+    Class     = 1 << 3,
+    Struct    = 1 << 4,
+    Enum      = 1 << 5,
+    Interface = 1 << 6,
+    Delegate  = 1 << 7,
+    // Member
+    Event     = 1 << 8,
+    Field     = 1 << 9,
+    Method    = 1 << 10,
+    Property  = 1 << 11,
+#pragma warning restore format
+
+    Type = Class | Struct | Enum | Interface | Delegate,
+    Member = Event | Field | Method | Property,
 }
 
+
 internal static class ExtendedSymbolKindHelper
 {
     public static bool Contains(this ExtendedSymbolKind kind, SymbolFilterData symbol)
@@ -30,6 +37,6 @@ public static bool Contains(this ExtendedSymbolKind kind, SymbolFilterData symbo
         {
             return false;
         }
-        return (kind & k.Value) == kind;
+        return (kind & k.Value) > 0;
     }
 }

test/Docfx.Dotnet.Tests/ApiFilterUnitTest.cs

@@ -327,6 +327,44 @@ public interface IClass1
         Assert.Empty(class1.Items);
     }
 
+    [Fact]
+    public void TestDocsSampleFilter()
+    {
+        var code = @"
+namespace Microsoft.DevDiv
+{
+    public class Class1
+    {
+    }
+}
+namespace Microsoft.DevDiv.SpecialCase
+{
+    public class NestedClass : Class1
+    {
+    }
+}
+";
+        string configFile = "TestData/filterconfig_docs_sample.yml";
+        MetadataItem output = Verify(code, new() { FilterConfigFile = configFile });
+
+        var namespaces = output.Items;
+        Assert.Single(namespaces);
+
+        var @namespace = namespaces[0];
+        Assert.NotNull(@namespace);
+        Assert.Equal("Microsoft.DevDiv.SpecialCase", @namespace.Name);
+        Assert.Single(@namespace.Items);
+
+        var nestedClass = @namespace.Items[0];
+        Assert.Equal("Microsoft.DevDiv.SpecialCase.NestedClass", nestedClass.Name);
+    }
+
+    [Fact]
+    public void TestExtendedSymbolKindFlags()
+    {
+        Assert.True((ExtendedSymbolKind.Type | ExtendedSymbolKind.Member).Contains(new SymbolFilterData { Kind = ExtendedSymbolKind.Interface }));
+    }
+
     private static MetadataItem Verify(string code, ExtractMetadataConfig config = null, DotnetApiOptions options = null)
     {
         var compilation = CompilationHelper.CreateCompilationFromCSharpCode(code, "test.dll");

test/Docfx.Dotnet.Tests/TestData/filterconfig_docs_sample.yml

@@ -0,0 +1,5 @@
+apiRules:
+- include:
+    uidRegex: ^Microsoft\.DevDiv\.SpecialCase
+- exclude:
+    uidRegex: ^Microsoft\.DevDiv