Better error message with UnboundLocalError

diff --git a/Python/ceval.c b/Python/ceval.c
index 4b40197c4e3b321951d0346203d9445023fcfab2..b399b638ea6ed853eb43da65c5ce044f4a9d9503 100644 (file)
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -73,7 +73,12 @@ static int exec_statement(PyFrameObject *,
                          PyObject *, PyObject *, PyObject *);
 static void set_exc_info(PyThreadState *, PyObject *, PyObject *, PyObject *);
 static void reset_exc_info(PyThreadState *);
+static void format_exc_check_arg(PyObject *, char *, PyObject *);
 
+#define NAME_ERROR_MSG \
+       "There is no variable named '%s'"
+#define UNBOUNDLOCAL_ERROR_MSG \
+       "Local variable '%.200s' referenced before assignment"
 
 /* Dynamic execution profile */
 #ifdef DYNAMIC_EXECUTION_PROFILE
@@ -1396,7 +1401,8 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
                                break;
                        }
                        if ((err = PyDict_DelItem(x, w)) != 0)
-                               PyErr_SetObject(PyExc_NameError, w);
+                               format_exc_check_arg(PyExc_NameError, 
+                                                       NAME_ERROR_MSG ,w);
                        break;
 
                case UNPACK_SEQUENCE:
@@ -1471,7 +1477,8 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
                case DELETE_GLOBAL:
                        w = GETNAMEV(oparg);
                        if ((err = PyDict_DelItem(f->f_globals, w)) != 0)
-                               PyErr_SetObject(PyExc_NameError, w);
+                               format_exc_check_arg(
+                                   PyExc_NameError, NAME_ERROR_MSG ,w);
                        break;
                
                case LOAD_CONST:
@@ -1493,8 +1500,9 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
                                if (x == NULL) {
                                        x = PyDict_GetItem(f->f_builtins, w);
                                        if (x == NULL) {
-                                               PyErr_SetObject(
-                                                       PyExc_NameError, w);
+                                               format_exc_check_arg(
+                                                           PyExc_NameError, 
+                                                           NAME_ERROR_MSG ,w);
                                                break;
                                        }
                                }
@@ -1509,7 +1517,9 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
                        if (x == NULL) {
                                x = PyDict_GetItem(f->f_builtins, w);
                                if (x == NULL) {
-                                       PyErr_SetObject(PyExc_NameError, w);
+                                       format_exc_check_arg(
+                                                   PyExc_NameError, 
+                                                   NAME_ERROR_MSG ,w);
                                        break;
                                }
                        }
@@ -1520,9 +1530,11 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
                case LOAD_FAST:
                        x = GETLOCAL(oparg);
                        if (x == NULL) {
-                               PyErr_SetObject(PyExc_UnboundLocalError,
-                                          PyTuple_GetItem(co->co_varnames,
-                                                       oparg));
+                               format_exc_check_arg(
+                                       PyExc_UnboundLocalError,
+                                       UNBOUNDLOCAL_ERROR_MSG,
+                                       PyTuple_GetItem(co->co_varnames, oparg)
+                                       );
                                break;
                        }
                        Py_INCREF(x);
@@ -1538,9 +1550,11 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
                case DELETE_FAST:
                        x = GETLOCAL(oparg);
                        if (x == NULL) {
-                               PyErr_SetObject(PyExc_UnboundLocalError,
-                                          PyTuple_GetItem(co->co_varnames,
-                                                       oparg));
+                               format_exc_check_arg(
+                                       PyExc_UnboundLocalError,
+                                       UNBOUNDLOCAL_ERROR_MSG,
+                                       PyTuple_GetItem(co->co_varnames, oparg)
+                                       );
                                break;
                        }
                        SETLOCAL(oparg, NULL);
@@ -3063,6 +3077,20 @@ exec_statement(PyFrameObject *f, PyObject *prog, PyObject *globals,
        return 0;
 }
 
+static void 
+format_exc_check_arg(PyObject *exc, char *format_str, PyObject *obj)
+{
+       char *obj_str;
+
+       if (!obj)
+               return;
+
+       obj_str = PyString_AsString(obj);
+       if (!obj_str)
+               return;
+
+       PyErr_Format(exc, format_str, obj_str);
+}
 
 #ifdef DYNAMIC_EXECUTION_PROFILE