Use enum rather than int for size_check.

Cython/Compiler/ModuleNode.py

@@ -3060,18 +3060,14 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
             code.put('sizeof(%s), ' % objstruct)
 
         # check_size
-        if not type.is_external or type.is_subclassed:
-            cs = 0
-        elif type.check_size == 'error':
-            cs = 0
-        elif type.check_size == 'warn':
-            cs = 1
-        elif type.check_size == 'ignore':
-            cs = 2
+        if type.check_size and type.check_size in ('error', 'warn', 'ignore'):
+            check_size = type.check_size
+        elif not type.is_external or type.is_subclassed:
+            check_size = 'error'
         else:
             raise RuntimeError("invalid value for check_size '%s' when compiling %s.%s" % (
                 type.check_size, module_name, type.name))
-        code.putln('%d);' % cs)
+        code.putln('__Pyx_ImportType_CheckSize_%s);' % check_size.title())
 
         code.putln(' if (!%s) %s' % (type.typeptr_cname, error_code))
 

Cython/Utility/ImportExport.c

@@ -309,14 +309,21 @@ set_path:
 /////////////// TypeImport.proto ///////////////
 
 
-static PyTypeObject *__Pyx_ImportType(PyObject* module, const char *module_name, const char *class_name, size_t size, int check_size);  /*proto*/
+enum __Pyx_ImportType_CheckSize {
+   __Pyx_ImportType_CheckSize_Error = 0,
+   __Pyx_ImportType_CheckSize_Warn = 1,
+   __Pyx_ImportType_CheckSize_Ignore = 2
+};
+
+
+static PyTypeObject *__Pyx_ImportType(PyObject* module, const char *module_name, const char *class_name, size_t size, enum __Pyx_ImportType_CheckSize check_size);  /*proto*/
 
 /////////////// TypeImport ///////////////
 
 #ifndef __PYX_HAVE_RT_ImportType
 #define __PYX_HAVE_RT_ImportType
 static PyTypeObject *__Pyx_ImportType(PyObject *module, const char *module_name, const char *class_name,
-    size_t size, int check_size)
+    size_t size, enum __Pyx_ImportType_CheckSize check_size)
 {
     /*
      * 'check_size' tells what to do if tp_basicsize is different from size:
@@ -359,21 +366,21 @@ static PyTypeObject *__Pyx_ImportType(PyObject *module, const char *module_name,
             module_name, class_name, size, basicsize);
         goto bad;
     }
-    if (check_size == 0 && (size_t)basicsize != size) {
+    if (check_size == __Pyx_ImportType_CheckSize_Error && (size_t)basicsize != size) {
         PyErr_Format(PyExc_ValueError,
             "%.200s.%.200s size changed, may indicate binary incompatibility. "
             "Expected %zd from C header, got %zd from PyObject",
             module_name, class_name, size, basicsize);
         goto bad;
     }
-    else if (check_size == 1 && (size_t)basicsize > size) {
+    else if (check_size == __Pyx_ImportType_CheckSize_Warn && (size_t)basicsize > size) {
         PyOS_snprintf(warning, sizeof(warning),
             "%s.%s size changed, may indicate binary incompatibility. "
             "Expected %zd from C header, got %zd from PyObject",
             module_name, class_name, size, basicsize);
         if (PyErr_WarnEx(NULL, warning, 0) < 0) goto bad;
     }
-    /* check_size == 2 does not warn nor error */
+    /* check_size == __Pyx_ImportType_CheckSize_Ignore does not warn nor error */
     return (PyTypeObject *)result;
 bad:
     Py_XDECREF(result);