Added tests for attributes, including a failing one (currently skipped)

Sources/DotNetMetadata/Attributable.swift

@@ -4,19 +4,19 @@ public protocol Attributable: AnyObject {
 }
 
 extension Attributable {
-    public func firstAttribute(namespace: String, name: String) throws -> Attribute? {
+    public func findAttribute(namespace: String?, name: String) throws -> Attribute? {
         try attributes.first { try $0.type.namespace == namespace && $0.type.name == name }
     }
 
-    public func hasAttribute(namespace: String, name: String) throws -> Bool {
-        try firstAttribute(namespace: namespace, name: name) != nil
+    public func hasAttribute(namespace: String?, name: String) throws -> Bool {
+        try findAttribute(namespace: namespace, name: name) != nil
     }
 
     public func hasAttribute<T: AttributeType>(_ type: T.Type) throws -> Bool {
         try attributes.contains { try $0.hasType(T.self) }
     }
 
-    public func firstAttribute<T: AttributeType>(_ type: T.Type) throws -> T.Value? {
+    public func findAttribute<T: AttributeType>(_ type: T.Type) throws -> T.Value? {
         guard let attribute = try attributes.first(where: { try $0.hasType(T.self) }) else { return nil }
         return try attribute.decode(as: T.self)
     }

Sources/DotNetMetadata/AttributeTargets.swift

@@ -13,7 +13,7 @@ public struct AttributeTargets: Hashable, OptionSet {
         Self(rawValue: left.rawValue & right.rawValue)
     }
 
-    public static let none = Self(rawValue: 0)
+    public static let none = Self([])
 
     /// Attribute can be applied to an assembly.
     public static let assembly = Self(rawValue: 1)

Sources/DotNetMetadata/AttributeType.swift

@@ -1,7 +1,7 @@
 public protocol AttributeType {
     associatedtype Value = Self
 
-    static var namespace: String { get }
+    static var namespace: String? { get }
     static var name: String { get }
     static var validOn: AttributeTargets { get }
     static var allowMultiple: Bool { get }

Sources/DotNetMetadata/Attributes/AttributeUsageAttribute.swift

@@ -9,7 +9,7 @@ public struct AttributeUsageAttribute: AttributeType {
         self.inherited = inherited
     }
 
-    public static var namespace: String { "System" }
+    public static var namespace: String? { "System" }
     public static var name: String { "AttributeUsageAttribute" }
     public static var validOn: AttributeTargets { .class }
     public static var allowMultiple: Bool { false }

Sources/DotNetMetadata/Attributes/ComImportAttribute.swift

@@ -1,5 +1,5 @@
 public enum ComImportAttribute: AttributeType {
-    public static var namespace: String { "System.Runtime.InteropServices" }
+    public static var namespace: String? { "System.Runtime.InteropServices" }
     public static var name: String { "ComImportAttribute" }
     public static var validOn: AttributeTargets { .class | .interface }
     public static var allowMultiple: Bool { false }

Sources/DotNetMetadata/Attributes/ComVisibleAttribute.swift

@@ -1,5 +1,5 @@
 public enum ComVisibleAttribute: AttributeType {
-    public static var namespace: String { "System.Runtime.InteropServices" }
+    public static var namespace: String? { "System.Runtime.InteropServices" }
     public static var name: String { "ComVisibleAttribute" }
     public static var validOn: AttributeTargets { .assembly | .allTypes | .method | .property | .field }
     public static var allowMultiple: Bool { false }

Sources/DotNetMetadata/Attributes/GuidAttribute.swift

@@ -1,5 +1,5 @@
 public enum GuidAttribute: AttributeType {
-    public static var namespace: String { "System.Runtime.InteropServices" }
+    public static var namespace: String? { "System.Runtime.InteropServices" }
     public static var name: String { "GuidAttribute" }
     public static var validOn: AttributeTargets { .assembly | .allTypes }
     public static var allowMultiple: Bool { false }

Sources/DotNetMetadataFormat/Signatures+reading.swift

@@ -64,6 +64,13 @@ extension CustomAttribSig {
                     try consumeElem(buffer: &buffer, type: element)
                 })
 
+            case .defOrRef(index: _, class: true, genericArgs: _):
+                // Assume a System.Type
+                guard let canonicalName = try consumeSerString(buffer: &buffer) else {
+                    throw InvalidFormatError.signatureBlob
+                }
+                fatalError()
+
             default: throw InvalidFormatError.signatureBlob
         }
     }

Sources/WindowsMetadata/ActivatableAttribute.swift

@@ -10,7 +10,7 @@ public struct ActivatableAttribute: AttributeType {
         self.applicability = applicability
     }
 
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "ActivatableAttribute" }
     public static var validOn: AttributeTargets { .class }
     public static var allowMultiple: Bool { true }

Sources/WindowsMetadata/AllowMultipleAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 
 /// Indicates that multiple instances of a custom attribute can be applied to a target.
 public enum AllowMultipleAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "AllowMultipleAttribute" }
     public static var validOn: AttributeTargets { .class }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/ApiContractAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 
 /// Specifies that the type represents an API contract.
 public enum ApiContractAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "ApiContractAttribute" }
     public static var validOn: AttributeTargets { .enum }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/ComposableAttribute.swift

@@ -20,7 +20,7 @@ public struct ComposableAttribute: AttributeType {
         self.applicability = applicability
     }
 
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "ComposableAttribute" }
     public static var validOn: AttributeTargets { .class }
     public static var allowMultiple: Bool { true }

Sources/WindowsMetadata/ContractVersionAttribute.swift

@@ -22,7 +22,7 @@ public struct ContractVersionAttribute: AttributeType {
         self.init(contract: .type(contract), version: version)
     }
 
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "ContractVersionAttribute" }
     public static var validOn: AttributeTargets { .allTypes | .allMembers }
     public static var allowMultiple: Bool { true }

Sources/WindowsMetadata/DefaultAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 
 /// Indicates the default interface for a runtime class.
 public enum DefaultAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "DefaultAttribute" }
     public static var validOn: AttributeTargets { .none } // No attribute target for interface implementations
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/DefaultOverloadAttribute.swift

@@ -3,7 +3,7 @@ import DotNetMetadata
 /// Indicates that a method is the default overload method.
 /// This attribute must be used with OverloadAttribute.
 public enum DefaultOverloadAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "DefaultOverloadAttribute" }
     public static var validOn: AttributeTargets { .method }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/DeprecatedAttribute.swift

@@ -19,7 +19,7 @@ public struct DeprecatedAttribute: AttributeType {
         self.applicability = applicability
     }
 
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "DeprecatedAttribute" }
     public static var validOn: AttributeTargets { .allTypes | .allMembers }
     public static var allowMultiple: Bool { true }

Sources/WindowsMetadata/DualApiPartitionAttribute.swift

@@ -1,7 +1,7 @@
 import DotNetMetadata
 
 public enum DualApiPartitionAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "DualApiPartitionAttribute" }
     public static var validOn: AttributeTargets { .class }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/ExclusiveToAttribute.swift

@@ -1,7 +1,7 @@
 import DotNetMetadata
 
 public enum ExclusiveToAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "ExclusiveToAttribute" }
     public static var validOn: AttributeTargets { .interface }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/ExperimentalAttribute.swift

@@ -3,7 +3,7 @@ import DotNetMetadata
 /// Indicates that a type or member should be marked in metadata as experimental, 
 /// and consequently may not be present in the final, released version of an SDK or library.
 public enum ExperimentalAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "ExperimentalAttribute" }
     public static var validOn: AttributeTargets { .allTypes }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/GuidAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 import struct Foundation.UUID
 
 public enum GuidAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "GuidAttribute" }
     public static var validOn: AttributeTargets { .interface | .delegate }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/InternalAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 
 /// Indicates that the interface contains internal methods.
 public enum InternalAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "InternalAttribute" }
     public static var validOn: AttributeTargets { .none } // No attribute target for interface implementations
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/LengthIsAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 
 /// Indicates the number of array elements.
 public enum LengthIsAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "LengthIsAttribute" }
     public static var validOn: AttributeTargets { .param }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/NoExceptionAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 
 /// Indicates that the interface contains protected methods.
 public enum NoExceptionAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "NoExceptionAttribute" }
     public static var validOn: AttributeTargets { .method | .property }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/OverloadAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 
 /// Identifies the method as an overload in a language that supports overloading.
 public enum OverloadAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "OverloadAttribute" }
     public static var validOn: AttributeTargets { .method }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/ProtectedAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 
 /// Indicates that the interface contains protected methods.
 public enum ProtectedAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "ProtectedAttribute" }
     public static var validOn: AttributeTargets { .none } // No attribute target for interface implementations
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/StaticAttribute.swift

@@ -10,7 +10,7 @@ public struct StaticAttribute: AttributeType {
         self.applicability = applicability
     }
 
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "StaticAttribute" }
     public static var validOn: AttributeTargets { .class }
     public static var allowMultiple: Bool { true }

Sources/WindowsMetadata/ThreadingAttribute.swift

@@ -2,7 +2,7 @@ import DotNetMetadata
 
 /// Indicates the threading model of a Windows Runtime component.
 public enum ThreadingAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "ThreadingAttribute" }
     public static var validOn: AttributeTargets { .class }
     public static var allowMultiple: Bool { false }

Sources/WindowsMetadata/VariantAttribute.swift

@@ -3,7 +3,7 @@ import DotNetMetadata
 /// Indicates that the item is an instance of a variant **IInspectable**.
 /// Applies to method parameters, properties, and return values of types.
 public enum VariantAttribute: AttributeType {
-    public static var namespace: String { "Windows.Foundation.Metadata" }
+    public static var namespace: String? { "Windows.Foundation.Metadata" }
     public static var name: String { "VariantAttribute" }
     public static var validOn: AttributeTargets { .property | .param }
     public static var allowMultiple: Bool { false }

Tests/UnitTests/DotNetMetadata/AttributeTests.swift

@@ -0,0 +1,108 @@
+@testable import DotNetMetadata
+import XCTest
+
+internal final class AttributeTests: CompiledAssemblyTestCase {
+    internal override class var csharpCode: String {
+        """
+        class MyAttributeAttribute: System.Attribute
+        {
+            public MyAttributeAttribute() {}
+            public MyAttributeAttribute(int i) {}
+            public MyAttributeAttribute(string s) {}
+            public MyAttributeAttribute(System.Type t) {}
+            public int Field;
+            public int Property { get; set; }
+        }
+
+        // Test attribute arguments
+        [MyAttribute(1)] struct IntArgument {}
+        [MyAttribute("1")] struct StringArgument {}
+        [MyAttribute(typeof(TypeArgument))] struct TypeArgument {}
+        [MyAttribute(Field = 42)] struct NamedFieldArgument {}
+        [MyAttribute(Property = 42)] struct NamedPropertyArgument {}
+        """
+    }
+
+    public func testNumericArgument() throws {
+        let targetType = try XCTUnwrap(assembly.findDefinedType(fullName: "IntArgument"))
+        let attribute = try XCTUnwrap(targetType.findAttribute(namespace: nil, name: "MyAttributeAttribute"))
+        let arguments = try attribute.arguments
+        XCTAssertEqual(arguments.count, 1)
+        XCTAssertEqual(try attribute.namedArguments.count, 0)
+        guard case .constant(.int32(let i)) = arguments.first else {
+            XCTFail("Expected int32")
+            return
+        }
+        XCTAssertEqual(i, 1)
+    }
+
+    public func testStringArgument() throws {
+        let targetType = try XCTUnwrap(assembly.findDefinedType(fullName: "StringArgument"))
+        let attribute = try XCTUnwrap(targetType.findAttribute(namespace: nil, name: "MyAttributeAttribute"))
+        let arguments = try attribute.arguments
+        XCTAssertEqual(arguments.count, 1)
+        XCTAssertEqual(try attribute.namedArguments.count, 0)
+        guard case .constant(.string(let s)) = arguments.first else {
+            XCTFail("Expected string")
+            return
+        }
+        XCTAssertEqual(s, "1")
+    }
+
+    public func testTypeArgument() throws {
+        try XCTSkipIf(true, "Currently crashes")
+
+        let targetType = try XCTUnwrap(assembly.findDefinedType(fullName: "TypeArgument"))
+        let attribute = try XCTUnwrap(targetType.findAttribute(namespace: nil, name: "MyAttributeAttribute"))
+        let arguments = try attribute.arguments
+        XCTAssertEqual(arguments.count, 1)
+        XCTAssertEqual(try attribute.namedArguments.count, 0)
+        guard case .type(let type) = arguments.first else {
+            XCTFail("Expected type")
+            return
+        }
+        XCTAssertIdentical(type, targetType)
+    }
+
+    public func testNamedFieldArgument() throws {
+        let targetType = try XCTUnwrap(assembly.findDefinedType(fullName: "NamedFieldArgument"))
+        let attribute = try XCTUnwrap(targetType.findAttribute(namespace: nil, name: "MyAttributeAttribute"))
+        XCTAssertEqual(try attribute.arguments.count, 0)
+        let namedArguments = try attribute.namedArguments
+        XCTAssertEqual(namedArguments.count, 1)
+        let namedArgument = try XCTUnwrap(namedArguments.first)
+
+        guard case .field(let field) = namedArgument.target else {
+            XCTFail("Expected field")
+            return
+        }
+        XCTAssertEqual(field.name, "Field")
+
+        guard case .constant(.int32(let value)) = namedArgument.value else {
+            XCTFail("Expected int32")
+            return
+        }
+        XCTAssertEqual(value, 42)
+    }
+
+    public func testNamedPropertyArgument() throws {
+        let targetType = try XCTUnwrap(assembly.findDefinedType(fullName: "NamedPropertyArgument"))
+        let attribute = try XCTUnwrap(targetType.findAttribute(namespace: nil, name: "MyAttributeAttribute"))
+        XCTAssertEqual(try attribute.arguments.count, 0)
+        let namedArguments = try attribute.namedArguments
+        XCTAssertEqual(namedArguments.count, 1)
+        let namedArgument = try XCTUnwrap(namedArguments.first)
+
+        guard case .property(let property) = namedArgument.target else {
+            XCTFail("Expected property")
+            return
+        }
+        XCTAssertEqual(property.name, "Property")
+
+        guard case .constant(.int32(let value)) = namedArgument.value else {
+            XCTFail("Expected int32")
+            return
+        }
+        XCTAssertEqual(value, 42)
+    }
+}