Fix repr() of oldstyle class infinite recursion. add _PyErr_BadInternalCall...

Fix repr() of oldstyle class infinite recursion. add _PyErr_BadInternalCall and PyCFunction_GetFlags

src/runtime/capi.cpp

@@ -56,7 +56,7 @@ BoxedClass* capifunc_cls;
 }
 
 extern "C" void _PyErr_BadInternalCall(const char* filename, int lineno) noexcept {
-    Py_FatalError("unimplemented");
+    PyErr_Format(PyExc_SystemError, "%s:%d: bad argument to internal function", filename, lineno);
 }
 
 extern "C" PyObject* PyObject_Format(PyObject* obj, PyObject* format_spec) noexcept {
@@ -1388,6 +1388,14 @@ extern "C" PyObject* PyCFunction_GetSelf(PyObject* op) noexcept {
     return static_cast<BoxedCApiFunction*>(op)->passthrough;
 }
 
+extern "C" int PyCFunction_GetFlags(PyObject* op) noexcept {
+    if (!PyCFunction_Check(op)) {
+        PyErr_BadInternalCall();
+        return -1;
+    }
+    return static_cast<BoxedCApiFunction*>(op)->method_def->ml_flags;
+}
+
 extern "C" int _PyEval_SliceIndex(PyObject* v, Py_ssize_t* pi) noexcept {
     if (v != NULL) {
         Py_ssize_t x;

src/runtime/classobj.cpp

@@ -267,6 +267,27 @@ Box* classobjStr(Box* _obj) {
     return boxStringTwine(llvm::Twine(static_cast<BoxedString*>(_mod)->s()) + "." + cls->name->s());
 }
 
+Box* classobjRepr(Box* _obj) {
+    if (!isSubclass(_obj->cls, classobj_cls)) {
+        raiseExcHelper(TypeError, "descriptor '__repr__' requires a 'classobj' object but received an '%s'",
+                       getTypeName(_obj));
+    }
+
+    BoxedClassobj* cls = static_cast<BoxedClassobj*>(_obj);
+
+    static BoxedString* module_str = internStringImmortal("__module__");
+    Box* mod = cls->getattr(module_str);
+
+    const char* name;
+    if (cls->name == NULL || !PyString_Check(cls->name))
+        name = "?";
+    else
+        name = PyString_AsString(cls->name);
+    if (mod == NULL || !PyString_Check(mod))
+        return PyString_FromFormat("<class ?.%s at %p>", name, cls);
+    else
+        return PyString_FromFormat("<class %s.%s at %p>", PyString_AsString(mod), name, cls);
+}
 
 // Analogous to CPython's instance_getattr2
 static Box* instanceGetattributeSimple(BoxedInstance* inst, BoxedString* attr_str,
@@ -1512,6 +1533,7 @@ void setupClassobj() {
                            new BoxedFunction(boxRTFunction((void*)classobjGetattribute, UNKNOWN, 2)));
     classobj_cls->giveAttr("__setattr__", new BoxedFunction(boxRTFunction((void*)classobjSetattr, UNKNOWN, 3)));
     classobj_cls->giveAttr("__str__", new BoxedFunction(boxRTFunction((void*)classobjStr, STR, 1)));
+    classobj_cls->giveAttr("__repr__", new BoxedFunction(boxRTFunction((void*)classobjRepr, STR, 1)));
     classobj_cls->giveAttr("__dict__", dict_descr);
 
     classobj_cls->freeze();