SystemExitBuiltins: set code to None when not specified but set the process return code to 0 if the code is set to None

Author: cosminbasca

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/SysModuleBuiltins.java

@@ -1581,7 +1581,7 @@ Object exit(@SuppressWarnings("unused") PythonModule sys, Object status) {
         @Specialization
         @SuppressWarnings("unused")
         Object exitNoCode(PythonModule sys, PNone status) {
-            throw raiseSystemExit(0);
+            throw raiseSystemExit(PNone.NONE);
         }
     }
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/exception/SystemExitBuiltins.java

@@ -105,8 +105,8 @@ public abstract static class InitNode extends PythonBuiltinNode {
         @Specialization
         Object initNoArgs(PBaseException self, Object[] args,
                         @Cached BaseExceptionBuiltins.BaseExceptionInitNode baseExceptionInitNode) {
-            self.setData(SystemExitData.create(factory(), args));
             baseExceptionInitNode.execute(self, args);
+            self.setData(SystemExitData.create(factory(), args));
             return PNone.NONE;
         }
     }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/control/TopLevelExceptionHandler.java

@@ -253,7 +253,9 @@ private static int getExitCode(PBaseException pythonException) throws CannotCast
         int exitcode = 0;
         if (data instanceof SystemExitBuiltins.SystemExitData) {
             final Object code = ((SystemExitBuiltins.SystemExitData) data).getCode();
-            exitcode = (int) CastToJavaLongLossyNode.getUncached().execute(code);
+            if (code != PNone.NONE) {
+                exitcode = (int) CastToJavaLongLossyNode.getUncached().execute(code);
+            }
         }
         return exitcode;
     }