From c18db8cee40acb8319840da2675d3de494ee262e Mon Sep 17 00:00:00 2001
From: Benedikt Reinartz <filmor@gmail.com>
Date: Mon, 11 Jul 2022 16:56:30 +0200
Subject: [PATCH] Fix missing docstring for types with custom constructors

---
 src/runtime/ClassManager.cs | 15 ++++++++++++---
 tests/test_docstring.py     |  7 +++++++
 tests/test_enum.py          |  5 ++---
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/runtime/ClassManager.cs b/src/runtime/ClassManager.cs
index 6c5558f3a..79ab20e82 100644
--- a/src/runtime/ClassManager.cs
+++ b/src/runtime/ClassManager.cs
@@ -87,7 +87,7 @@ internal static ClassManagerState SaveRuntimeData()
                     if ((Runtime.PyDict_DelItemString(dict.Borrow(), member) == -1) &&
                         (Exceptions.ExceptionMatches(Exceptions.KeyError)))
                     {
-                        // Trying to remove a key that's not in the dictionary 
+                        // Trying to remove a key that's not in the dictionary
                         // raises an error. We don't care about it.
                         Runtime.PyErr_Clear();
                     }
@@ -215,7 +215,7 @@ internal static void InitClassBase(Type type, ClassBase impl, ReflectedClrType p
             impl.indexer = info.indexer;
             impl.richcompare.Clear();
 
-            
+
             // Finally, initialize the class __dict__ and return the object.
             using var newDict = Runtime.PyObject_GenericGetDict(pyType.Reference);
             BorrowedReference dict = newDict.Borrow();
@@ -271,6 +271,15 @@ internal static void InitClassBase(Type type, ClassBase impl, ReflectedClrType p
                         Runtime.PyDict_SetItem(dict, PyIdentifier.__doc__, doc.Borrow());
                     }
                 }
+
+                if (Runtime.PySequence_Contains(dict, PyIdentifier.__doc__) != 1)
+                {
+                    // Ensure that at least some doc string is set
+                    using var fallbackDoc = Runtime.PyString_FromString(
+                        $"Python wrapper for .NET type {type}"
+                    );
+                    Runtime.PyDict_SetItem(dict, PyIdentifier.__doc__, fallbackDoc.Borrow());
+                }
             }
             doc.Dispose();
 
@@ -562,7 +571,7 @@ private static ClassInfo GetClassInfo(Type type, ClassBase impl)
 
             return ci;
         }
-        
+
         /// <summary>
         /// This class owns references to PyObjects in the `members` member.
         /// The caller has responsibility to DECREF them.
diff --git a/tests/test_docstring.py b/tests/test_docstring.py
index 640a61915..36c925a74 100644
--- a/tests/test_docstring.py
+++ b/tests/test_docstring.py
@@ -25,3 +25,10 @@ def test_doc_without_ctor():
     assert DocWithoutCtorTest.__doc__ == 'DocWithoutCtorTest Class'
     assert DocWithoutCtorTest.TestMethod.__doc__ == 'DocWithoutCtorTest TestMethod'
     assert DocWithoutCtorTest.StaticTestMethod.__doc__ == 'DocWithoutCtorTest StaticTestMethod'
+
+
+def test_doc_primitve():
+    from System import Int64, String
+
+    assert Int64.__doc__ is not None
+    assert String.__doc__ is not None
diff --git a/tests/test_enum.py b/tests/test_enum.py
index 981fb735c..f24f95b36 100644
--- a/tests/test_enum.py
+++ b/tests/test_enum.py
@@ -15,7 +15,6 @@ def test_enum_standard_attrs():
     assert DayOfWeek.__name__ == 'DayOfWeek'
     assert DayOfWeek.__module__ == 'System'
     assert isinstance(DayOfWeek.__dict__, DictProxyType)
-    assert DayOfWeek.__doc__ is None
 
 
 def test_enum_get_member():
@@ -139,7 +138,7 @@ def test_enum_undefined_value():
     # This should fail because our test enum doesn't have it.
     with pytest.raises(ValueError):
         Test.FieldTest().EnumField = Test.ShortEnum(20)
-    
+
     # explicitly permit undefined values
     Test.FieldTest().EnumField = Test.ShortEnum(20, True)
 
@@ -157,6 +156,6 @@ def test_enum_conversion():
 
     with pytest.raises(TypeError):
         Test.FieldTest().EnumField = "str"
-    
+
     with pytest.raises(TypeError):
         Test.FieldTest().EnumField = 1