Add __bool__ for MetaType (#102)

* Add __bool__ for MetaType

* Bump version to 2.0.44

* Minor fix

Author: jhonabreul

src/embed_tests/ClassManagerTests.cs

@@ -1085,6 +1085,33 @@ def is_enum_value_defined():
             }
         }
 
+        [Test]
+        public void TruthinessCanBeCheckedForTypes()
+        {
+            using (Py.GIL())
+            {
+                var module = PyModule.FromString("TruthinessCanBeCheckedForTypes", $@"
+from clr import AddReference
+AddReference(""Python.EmbeddingTest"")
+
+from Python.EmbeddingTest import *
+
+def throw_if_falsy():
+    if not ClassManagerTests:
+        raise Exception(""ClassManagerTests is falsy"")
+
+def throw_if_not_truthy():
+    if ClassManagerTests:
+        return
+    raise Exception(""ClassManagerTests is not truthy"")
+");
+
+                // Types are always truthy
+                Assert.DoesNotThrow(() => module.InvokeMethod("throw_if_falsy"));
+                Assert.DoesNotThrow(() => module.InvokeMethod("throw_if_not_truthy"));
+            }
+        }
+
         private static TestCaseData[] IDictionaryContainsTestCases =>
         [
             new(typeof(TestDictionary<string, string>)),

src/perf_tests/Python.PerformanceTests.csproj

@@ -13,7 +13,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.*" />
-    <PackageReference Include="quantconnect.pythonnet" Version="2.0.43" GeneratePathProperty="true">
+    <PackageReference Include="quantconnect.pythonnet" Version="2.0.44" GeneratePathProperty="true">
       <IncludeAssets>compile</IncludeAssets>
     </PackageReference>
   </ItemGroup>
@@ -25,7 +25,7 @@
   </Target>
 
   <Target Name="CopyBaseline" AfterTargets="Build">
-    <Copy SourceFiles="$(NuGetPackageRoot)quantconnect.pythonnet\2.0.43\lib\net9.0\Python.Runtime.dll" DestinationFolder="$(OutDir)baseline" />
+    <Copy SourceFiles="$(NuGetPackageRoot)quantconnect.pythonnet\2.0.44\lib\net9.0\Python.Runtime.dll" DestinationFolder="$(OutDir)baseline" />
   </Target>
 
   <Target Name="CopyNewBuild" AfterTargets="Build">

src/runtime/Native/ITypeOffsets.cs

@@ -30,6 +30,7 @@ interface ITypeOffsets
         int nb_invert { get; }
         int nb_inplace_add { get; }
         int nb_inplace_subtract { get; }
+        int nb_bool { get; }
         int ob_size { get; }
         int ob_type { get; }
         int qualname { get; }

src/runtime/Native/TypeOffset.cs

@@ -37,6 +37,7 @@ static partial class TypeOffset
         internal static int nb_invert { get; private set; }
         internal static int nb_inplace_add { get; private set; }
         internal static int nb_inplace_subtract { get; private set; }
+        internal static int nb_bool { get; private set; }
         internal static int ob_size { get; private set; }
         internal static int ob_type { get; private set; }
         internal static int qualname { get; private set; }

src/runtime/Properties/AssemblyInfo.cs

@@ -4,5 +4,5 @@
 [assembly: InternalsVisibleTo("Python.EmbeddingTest, PublicKey=00240000048000009400000006020000002400005253413100040000110000005ffd8f49fb44ab0641b3fd8d55e749f716e6dd901032295db641eb98ee46063cbe0d4a1d121ef0bc2af95f8a7438d7a80a3531316e6b75c2dae92fb05a99f03bf7e0c03980e1c3cfb74ba690aca2f3339ef329313bcc5dccced125a4ffdc4531dcef914602cd5878dc5fbb4d4c73ddfbc133f840231343e013762884d6143189")]
 [assembly: InternalsVisibleTo("Python.Test, PublicKey=00240000048000009400000006020000002400005253413100040000110000005ffd8f49fb44ab0641b3fd8d55e749f716e6dd901032295db641eb98ee46063cbe0d4a1d121ef0bc2af95f8a7438d7a80a3531316e6b75c2dae92fb05a99f03bf7e0c03980e1c3cfb74ba690aca2f3339ef329313bcc5dccced125a4ffdc4531dcef914602cd5878dc5fbb4d4c73ddfbc133f840231343e013762884d6143189")]
 
-[assembly: AssemblyVersion("2.0.43")]
-[assembly: AssemblyFileVersion("2.0.43")]
+[assembly: AssemblyVersion("2.0.44")]
+[assembly: AssemblyFileVersion("2.0.44")]

src/runtime/Python.Runtime.csproj

@@ -5,7 +5,7 @@
     <RootNamespace>Python.Runtime</RootNamespace>
     <AssemblyName>Python.Runtime</AssemblyName>
     <PackageId>QuantConnect.pythonnet</PackageId>
-    <Version>2.0.43</Version>
+    <Version>2.0.44</Version>
     <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
     <PackageLicenseFile>LICENSE</PackageLicenseFile>
     <RepositoryUrl>https://github.com/pythonnet/pythonnet</RepositoryUrl>

src/runtime/Types/MetaType.cs

@@ -386,6 +386,16 @@ public static int mp_length(BorrowedReference tp)
             return Enum.GetValues(type).Length;
         }
 
+        /// <summary>
+        /// Implements __bool__ for types, so that Python uses this instead of __len__ as default.
+        /// For types, this is always "true"
+        /// </summary>
+        public static int nb_bool(BorrowedReference tp)
+        {
+            var cb = GetManagedObject(tp) as ClassBase;
+            return cb == null || !cb.type.Valid ? 0 : 1;
+        }
+
         /// <summary>
         /// Implements __contains__ for Enum types.
         /// </summary>