added debug information for failures to create a derived type

lostmsu · lostmsu · commit a21a388c81e9 · 2020-12-17T13:39:55.000-08:00
diff --git a/src/runtime/NewReference.cs b/src/runtime/NewReference.cs
@@ -36,6 +36,27 @@ public IntPtr DangerousMoveToPointerOrNull()
             return result;
         }
 
+        /// <summary>
+        /// Moves ownership of this reference to a Python C API function,
+        /// that steals reference passed to it.
+        /// </summary>
+        public StolenReference Steal()
+        {
+            if (this.IsNull()) throw new NullReferenceException();
+
+            return this.StealOrNull();
+        }
+        /// <summary>
+        /// Moves ownership of this reference to a Python C API function,
+        /// that steals reference passed to it.
+        /// </summary>
+        public StolenReference StealOrNull()
+        {
+            IntPtr rawPointer = this.pointer;
+            this.pointer = IntPtr.Zero;
+            return new StolenReference(rawPointer);
+        }
+
         /// <summary>
         /// Removes this reference to a Python object, and sets it to <c>null</c>.
         /// </summary>
diff --git a/src/runtime/StolenReference.cs b/src/runtime/StolenReference.cs
@@ -0,0 +1,18 @@
+namespace Python.Runtime
+{
+    using System;
+
+    /// <summary>
+    /// Should only be used for the arguments of Python C API functions, that steal references
+    /// </summary>
+    [NonCopyable]
+    readonly ref struct StolenReference
+    {
+        readonly IntPtr pointer;
+
+        internal StolenReference(IntPtr pointer)
+        {
+            this.pointer = pointer;
+        }
+    }
+}
diff --git a/src/runtime/exceptions.cs b/src/runtime/exceptions.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics;
 using System.Reflection;
 using System.Runtime.InteropServices;
 
@@ -374,6 +375,18 @@ internal static IntPtr RaiseTypeError(string message)
             return IntPtr.Zero;
         }
 
+        internal static IntPtr SetCause(Exception cause) {
+            Runtime.PyErr_Fetch(out NewReference ob, out NewReference val, out NewReference tb);
+            Debug.Assert(!ob.IsNull() || !val.IsNull());
+            Runtime.PyErr_NormalizeException(ref ob, ref val, ref tb);
+
+            var causePyObj = NewReference.DangerousFromPointer(Converter.ToPython(cause));
+            Runtime.PyException_SetCause(ob, causePyObj.Steal());
+
+            Runtime.PyErr_Restore(ob.Steal(), val.StealOrNull(), tb.StealOrNull());
+            return IntPtr.Zero;
+        }
+
         // 2010-11-16: Arranged in python (2.6 & 2.7) source header file order
         /* Predefined exceptions are
            puplic static variables on the Exceptions class filled in from
diff --git a/src/runtime/runtime.cs b/src/runtime/runtime.cs
@@ -2034,23 +2034,32 @@ internal static IntPtr PyMem_Realloc(IntPtr ptr, long size)
         internal static extern int PyErr_GivenExceptionMatches(IntPtr ob, IntPtr val);
 
         [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
-        internal static extern void PyErr_NormalizeException(IntPtr ob, IntPtr val, IntPtr tb);
+        internal static extern void PyErr_NormalizeException(ref NewReference ob, ref NewReference val, ref NewReference tb);
 
         [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
         internal static extern IntPtr PyErr_Occurred();
 
         [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
         internal static extern void PyErr_Fetch(out IntPtr ob, out IntPtr val, out IntPtr tb);
+        [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
+        internal static extern void PyErr_Fetch(out NewReference ob, out NewReference val, out NewReference tb);
 
         [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
         internal static extern void PyErr_Restore(IntPtr ob, IntPtr val, IntPtr tb);
+        [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
+        internal static extern void PyErr_Restore(StolenReference ob, StolenReference val, StolenReference tb);
 
         [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
         internal static extern void PyErr_Clear();
 
         [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
         internal static extern void PyErr_Print();
 
+        [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
+        internal static extern void PyException_SetCause(BorrowedReference ex, StolenReference cause);
+        [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
+        internal static extern int PyException_SetTraceback(BorrowedReference ex, BorrowedReference cause);
+
         //====================================================================
         // Cell API
         //====================================================================
diff --git a/src/runtime/typemanager.cs b/src/runtime/typemanager.cs
@@ -384,7 +384,9 @@ internal static IntPtr CreateSubType(IntPtr py_name, IntPtr py_base_type, IntPtr
             }
             catch (Exception e)
             {
-                return Exceptions.RaiseTypeError(e.Message);
+                Exceptions.RaiseTypeError("unable to create derived type");
+                Exceptions.SetCause(e);
+                return IntPtr.Zero;
             }
         }
 

Original file line number	Diff line number	Diff line change
`@@ -384,7 +384,9 @@ internal static IntPtr CreateSubType(IntPtr py_name, IntPtr py_base_type, IntPtr`
`384`	`384`	`}`
`385`	`385`	`catch (Exception e)`
`386`	`386`	`{`
`387`		`- return Exceptions.RaiseTypeError(e.Message);`
	`387`	`+ Exceptions.RaiseTypeError("unable to create derived type");`
	`388`	`+ Exceptions.SetCause(e);`
	`389`	`+ return IntPtr.Zero;`
`388`	`390`	`}`
`389`	`391`	`}`
`390`	`392`