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lostmsulostmsu
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fixed debug assert when inheriting from RuntimeError
This simplifies and generalizes logic for allocating extra fields when inheriting from Python classes. The new class instance size is base_size + clr_pointer_size + (optional, only if not in the base already) weaklist&dict
1 parent 9cc2b45 commit 7555dec

3 files changed

Lines changed: 49 additions & 29 deletions

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‎src/embed_tests/Inheritance.cs‎

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -104,6 +104,26 @@ public void PythonCanSetAdHocAttributes() {
104104
Assert.AreEqual(expected: Inherited.X, actual);
105105
}
106106
}
107+
108+
[Test]
109+
public void FromException() {
110+
using var _ = Py.GIL();
111+
var runtimeError = PythonEngine.Eval("RuntimeError");
112+
PythonEngine.InteropConfiguration.PythonBaseTypeProviders.Add(
113+
new TestRuntimeError.BaseProvdier());
114+
var instance = new TestRuntimeError().ToPython();
115+
bool isRuntimeError = PyIsInstance(instance, runtimeError);
116+
Assert.IsTrue(isRuntimeError);
117+
}
118+
}
119+
120+
public class TestRuntimeError: Exception {
121+
internal class BaseProvdier: IPythonBaseTypeProvider {
122+
public IEnumerable<PyObject> GetBaseTypes(Type type, IList<PyObject> existingBases)
123+
=> type != typeof(TestRuntimeError)
124+
? existingBases
125+
: new[] { PythonEngine.Eval("RuntimeError") };
126+
}
107127
}
108128

109129
class CustomBaseTypeProvider : IPythonBaseTypeProvider {

‎src/runtime/interop.cs‎

Lines changed: 8 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -111,16 +111,18 @@ internal static void ClrGcHandleOffsetAssertSanity(int offset)
111111
/// <summary>
112112
/// Returns dict offset in instances of the specified <paramref name="type"/>
113113
/// </summary>
114-
public static int TypeDictOffset(BorrowedReference type) {
114+
public static unsafe int TypeDictOffset(BorrowedReference type) {
115+
#if DEBUG
115116
if (!Runtime.PyType_Check(type))
116117
throw new ArgumentException("Bad object type");
118+
#endif
117119

118-
return IsExceptionSubtype(type)
119-
? ExceptionOffset.ob_dict
120-
: ob_dict;
120+
IntPtr dictoffset = type.DangerousGetAddress() + TypeOffset.tp_dictoffset;
121+
int dict = *((int*)(dictoffset));
122+
Debug.Assert(dict > 0 && dict < 100_000);
123+
return dict;
121124
}
122-
public static int TypeDictOffset(IntPtr type)
123-
=> TypeDictOffset(new BorrowedReference(type));
125+
public static int TypeDictOffset() => ob_dict;
124126

125127
public static int Size(IntPtr ob) {
126128
if ((Runtime.PyObject_TypeCheck(ob, Exceptions.BaseException) ||

‎src/runtime/typemanager.cs‎

Lines changed: 21 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -88,7 +88,7 @@ internal static IntPtr CreateType(Type impl)
8888
// Set tp_basicsize to the size of our managed instance objects.
8989
Marshal.WriteIntPtr(type, TypeOffset.tp_basicsize, (IntPtr)ob_size);
9090

91-
var offset = (IntPtr)ObjectOffset.TypeDictOffset(type);
91+
var offset = (IntPtr)ObjectOffset.TypeDictOffset();
9292
Marshal.WriteIntPtr(type, TypeOffset.tp_dictoffset, offset);
9393

9494
InitializeSlots(type, impl);
@@ -109,21 +109,11 @@ internal static IntPtr CreateType(Type impl)
109109
return type;
110110
}
111111

112-
113112
internal static IntPtr CreateType(ManagedType impl, Type clrType)
114113
{
115114
string name = GetPythonTypeName(clrType);
116115

117116
int ob_size;
118-
int tp_dictoffset = ObjectOffset.TypeDictOffset(Runtime.PyTypeType);
119-
120-
// XXX Hack, use a different base class for System.Exception
121-
// Python 2.5+ allows new style class exceptions but they *must*
122-
// subclass BaseException (or better Exception).
123-
if (typeof(Exception).IsAssignableFrom(clrType))
124-
{
125-
tp_dictoffset = ObjectOffset.TypeDictOffset(Exceptions.Exception);
126-
}
127117

128118
IntPtr type = AllocateTypeObject(name, typeType: Runtime.PyCLRMetaType);
129119

@@ -159,22 +149,29 @@ internal static IntPtr CreateType(ManagedType impl, Type clrType)
159149
Marshal.WriteIntPtr(type, TypeOffset.tp_bases, baseTuple.Reference.DangerousIncRefOrNull());
160150
}
161151

162-
int baseSize = primaryBase == Runtime.PyBaseObjectType ? ObjectOffset.PyObject_HEAD_Size()
163-
: primaryBase == Exceptions.Exception ? ExceptionOffset.Size()
164-
: checked((int)Marshal.ReadIntPtr(primaryBase, TypeOffset.tp_basicsize));
165-
if (!ManagedType.IsManagedType(primaryBase))
166-
{
152+
ob_size = checked((int)Marshal.ReadIntPtr(primaryBase, TypeOffset.tp_basicsize));
153+
void InheritOrAllocate(int typeField) {
154+
int value = Marshal.ReadInt32(primaryBase, typeField);
155+
if (value == 0) {
156+
Marshal.WriteIntPtr(type, typeField, new IntPtr(ob_size));
157+
ob_size += IntPtr.Size;
158+
} else {
159+
Marshal.WriteIntPtr(type, typeField, new IntPtr(value));
160+
}
161+
}
162+
163+
InheritOrAllocate(TypeOffset.tp_dictoffset);
164+
InheritOrAllocate(TypeOffset.tp_weaklistoffset);
165+
166+
if (!ManagedType.IsManagedType(primaryBase)) {
167167
// base type is a Python type, so we must allocate additional space for GC handle
168-
extraTypeDataOffset = baseSize;
168+
extraTypeDataOffset = ob_size;
169169
ObjectOffset.ClrGcHandleOffsetAssertSanity(extraTypeDataOffset);
170-
ob_size = baseSize + MetaType.ExtraTypeDataSize;
171-
} else
172-
{
170+
ob_size += MetaType.ExtraTypeDataSize;
171+
} else {
173172
extraTypeDataOffset = checked((int)Marshal.ReadIntPtr(primaryBase, TypeOffset.clr_gchandle_offset));
174173
ObjectOffset.ClrGcHandleOffsetAssertSanity(extraTypeDataOffset);
175-
ob_size = baseSize;
176174
}
177-
Debug.Assert(extraTypeDataOffset > tp_dictoffset);
178175
}
179176
catch (Exception error)
180177
{
@@ -186,7 +183,6 @@ internal static IntPtr CreateType(ManagedType impl, Type clrType)
186183

187184
Marshal.WriteIntPtr(type, TypeOffset.tp_basicsize, (IntPtr)ob_size);
188185
Marshal.WriteIntPtr(type, TypeOffset.tp_itemsize, IntPtr.Zero);
189-
Marshal.WriteIntPtr(type, TypeOffset.tp_dictoffset, (IntPtr)tp_dictoffset);
190186
Marshal.WriteIntPtr(type, TypeOffset.clr_gchandle_offset, (IntPtr)extraTypeDataOffset);
191187

192188
var flags = TypeFlags.Default;
@@ -206,6 +202,8 @@ internal static IntPtr CreateType(ManagedType impl, Type clrType)
206202
return IntPtr.Zero;
207203
}
208204

205+
Debug.Assert(extraTypeDataOffset > Marshal.ReadInt32(type, TypeOffset.tp_dictoffset));
206+
209207
IntPtr dict = Marshal.ReadIntPtr(type, TypeOffset.tp_dict);
210208
string mn = clrType.Namespace ?? "";
211209
IntPtr mod = Runtime.PyString_FromString(mn);

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