Add PythonContext.GetCopyRegModule (#965)

Author: slozier

Src/IronPython.Modules/re.cs

@@ -35,7 +35,11 @@ public static class PythonRegex {
         [SpecialName]
         public static void PerformModuleReload(PythonContext/*!*/ context, PythonDictionary/*!*/ dict) {
             context.EnsureModuleException("reerror", dict, "error", "re");
-            PythonCopyReg.GetDispatchTable(context.SharedContext)[DynamicHelpers.GetPythonTypeFromType(typeof(Pattern))] = dict["_pickle"];
+            var module = context.GetCopyRegModule();
+            if (module != null) {
+                var pickle = PythonOps.GetBoundAttr(context.SharedContext, module, "pickle");
+                PythonOps.CallWithContext(context.SharedContext, pickle, DynamicHelpers.GetPythonTypeFromType(typeof(Pattern)), dict["_pickle"]);
+            }
         }
 
         private static readonly Random r = new Random(DateTime.Now.Millisecond);

Src/IronPython/Runtime/PythonContext.cs

@@ -1111,6 +1111,15 @@ internal PythonModule GetReloadableModule(PythonModule/*!*/ module) {
 
         #endregion
 
+        private object copyRegModule;
+
+        internal object GetCopyRegModule() {
+            if (copyRegModule is null) {
+                copyRegModule = Importer.ImportModule(SharedContext, new PythonDictionary(), "copyreg", false, 0);
+            }
+            return copyRegModule;
+        }
+
         public object GetWarningsModule() {
             object warnings = null;
             try {