Fixes bug where there is casting on delegates -- this is explicitly in the NET standard documentation for GetDelegateForFunctionPointer (pythonnet#936)

jmlidbetter · filmor · commit f1da55e5d13f · 2019-08-26T14:13:38.000+02:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -17,11 +17,13 @@ This document follows the conventions laid out in [Keep a CHANGELOG][].
 -   Moved wheel import in setup.py inside of a try/except to prevent pip collection failures
 -   Removes PyLong_GetMax and PyClass_New when targetting Python3
 -   Added support for converting python iterators to C# arrays
+-   Changed usage of obselete function GetDelegateForFunctionPointer(IntPtr, Type) to GetDelegateForFunctionPointer<TDelegate>(IntPtr)
 
 ### Fixed
 
 - Fixed runtime that fails loading when using pythonnet in an environment
   together with Nuitka
+- Fixes bug where delegates get casts (dotnetcore)
 
 ## [2.4.0][]
 
diff --git a/src/runtime/nativecall.cs b/src/runtime/nativecall.cs
@@ -32,19 +32,21 @@ internal class NativeCall
 
         public static void Void_Call_1(IntPtr fp, IntPtr a1)
         {
-            ((Void_1_Delegate)Marshal.GetDelegateForFunctionPointer(fp, typeof(Void_1_Delegate)))(a1);
+            var d = Marshal.GetDelegateForFunctionPointer<Interop.DestructorFunc>(fp);
+            d(a1);
         }
 
         public static IntPtr Call_3(IntPtr fp, IntPtr a1, IntPtr a2, IntPtr a3)
         {
-            var d = (Interop.TernaryFunc)Marshal.GetDelegateForFunctionPointer(fp, typeof(Interop.TernaryFunc));
+            var d = Marshal.GetDelegateForFunctionPointer<Interop.TernaryFunc>(fp);
             return d(a1, a2, a3);
         }
 
 
         public static int Int_Call_3(IntPtr fp, IntPtr a1, IntPtr a2, IntPtr a3)
         {
-            return ((Int_3_Delegate)Marshal.GetDelegateForFunctionPointer(fp, typeof(Int_3_Delegate)))(a1, a2, a3);
+            var d = Marshal.GetDelegateForFunctionPointer<Interop.ObjObjArgFunc>(fp);
+            return d(a1, a2, a3);
         }
 #else
         private static AssemblyBuilder aBuilder;

Original file line number	Diff line number	Diff line change
`@@ -32,19 +32,21 @@ internal class NativeCall`
`32`	`32`
`33`	`33`	`public static void Void_Call_1(IntPtr fp, IntPtr a1)`
`34`	`34`	`{`
`35`		`- ((Void_1_Delegate)Marshal.GetDelegateForFunctionPointer(fp, typeof(Void_1_Delegate)))(a1);`
	`35`	`+ var d = Marshal.GetDelegateForFunctionPointer<Interop.DestructorFunc>(fp);`
	`36`	`+ d(a1);`
`36`	`37`	`}`
`37`	`38`
`38`	`39`	`public static IntPtr Call_3(IntPtr fp, IntPtr a1, IntPtr a2, IntPtr a3)`
`39`	`40`	`{`
`40`		`- var d = (Interop.TernaryFunc)Marshal.GetDelegateForFunctionPointer(fp, typeof(Interop.TernaryFunc));`
	`41`	`+ var d = Marshal.GetDelegateForFunctionPointer<Interop.TernaryFunc>(fp);`
`41`	`42`	`return d(a1, a2, a3);`
`42`	`43`	`}`
`43`	`44`
`44`	`45`
`45`	`46`	`public static int Int_Call_3(IntPtr fp, IntPtr a1, IntPtr a2, IntPtr a3)`
`46`	`47`	`{`
`47`		`- return ((Int_3_Delegate)Marshal.GetDelegateForFunctionPointer(fp, typeof(Int_3_Delegate)))(a1, a2, a3);`
	`48`	`+ var d = Marshal.GetDelegateForFunctionPointer<Interop.ObjObjArgFunc>(fp);`
	`49`	`+ return d(a1, a2, a3);`
`48`	`50`	`}`
`49`	`51`	`#else`
`50`	`52`	`private static AssemblyBuilder aBuilder;`