fixup! Return the suggestion as a object and handle it in print_exception

Author: pablogsal

Doc/library/exceptions.rst

@@ -154,6 +154,8 @@ The following exceptions are the exceptions that are usually raised.
    that was attempted to be accessed and the object that was accessed for said
    attribute, respectively.
 
+   .. versionchanged:: 3.10
+      Added the :attr:`name` and :attr:`obj` attributes.
 
 .. exception:: EOFError
 

Include/internal/pycore_pyerrors.h

@@ -86,6 +86,8 @@ PyAPI_FUNC(int) _PyErr_CheckSignalsTstate(PyThreadState *tstate);
 
 PyAPI_FUNC(void) _Py_DumpExtensionModules(int fd, PyInterpreterState *interp);
 
+extern PyObject* _Py_Offer_Suggestions(PyObject* exception);
+
 #ifdef __cplusplus
 }
 #endif

Include/internal/pycore_suggestions.h

@@ -1162,7 +1162,6 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/internal/pycore_list.h \
 		$(srcdir)/Include/internal/pycore_long.h \
 		$(srcdir)/Include/internal/pycore_object.h \
-		$(srcdir)/Include/internal/pycore_suggestions.h \
 		$(srcdir)/Include/internal/pycore_pathconfig.h \
 		$(srcdir)/Include/internal/pycore_pyarena.h \
 		$(srcdir)/Include/internal/pycore_pyerrors.h \

Makefile.pre.in

@@ -12,7 +12,6 @@
 #include "pycore_pystate.h"       // _PyThreadState_GET()
 #include "pycore_symtable.h"      // PySTEntry_Type
 #include "pycore_unionobject.h"   // _Py_UnionType
-#include "pycore_suggestions.h"
 #include "frameobject.h"
 #include "interpreteridobject.h"
 
@@ -911,14 +910,14 @@ PyObject *
 PyObject_GetAttr(PyObject *v, PyObject *name)
 {
     PyTypeObject *tp = Py_TYPE(v);
-    PyObject* result = NULL;
-
     if (!PyUnicode_Check(name)) {
         PyErr_Format(PyExc_TypeError,
                      "attribute name must be string, not '%.200s'",
                      Py_TYPE(name)->tp_name);
         return NULL;
     }
+
+    PyObject* result = NULL;
     if (tp->tp_getattro != NULL) {
         result = (*tp->tp_getattro)(v, name);
     }

Objects/object.c

@@ -215,7 +215,6 @@
     <ClInclude Include="..\Include\internal\pycore_ucnhash.h" />
     <ClInclude Include="..\Include\internal\pycore_unionobject.h" />
     <ClInclude Include="..\Include\internal\pycore_warnings.h" />
-    <ClInclude Include="..\Include\internal\pycore_suggestions.h" />
     <ClInclude Include="..\Include\interpreteridobject.h" />
     <ClInclude Include="..\Include\intrcheck.h" />
     <ClInclude Include="..\Include\iterobject.h" />

PCbuild/pythoncore.vcxproj

@@ -15,7 +15,7 @@
 #include "pycore_interp.h"        // PyInterpreterState.importlib
 #include "pycore_object.h"        // _PyDebug_PrintTotalRefs()
 #include "pycore_parser.h"        // _PyParser_ASTFromString()
-#include "pycore_pyerrors.h"      // _PyErr_Fetch
+#include "pycore_pyerrors.h"      // _PyErr_Fetch, _Py_Offer_Suggestions
 #include "pycore_pylifecycle.h"   // _Py_UnhandledKeyboardInterrupt
 #include "pycore_pystate.h"       // _PyInterpreterState_GET()
 #include "pycore_sysmodule.h"     // _PySys_Audit()
@@ -24,7 +24,6 @@
 #include "errcode.h"              // E_EOF
 #include "code.h"                 // PyCodeObject
 #include "marshal.h"              // PyMarshal_ReadLongFromFile()
-#include "pycore_suggestions.h"   // _Py_Offer_Suggestions
 
 #ifdef MS_WINDOWS
 #  include "malloc.h"             // alloca()
@@ -956,9 +955,11 @@ print_exception(PyObject *f, PyObject *value)
     }
     PyObject* suggestions = _Py_Offer_Suggestions(value);
     if (suggestions) {
-        err = PyFile_WriteString(". ", f);
+        // Add a trailer ". Did you mean: (...)?"
+        err = PyFile_WriteString(". Did you mean: ", f);
         if (err == 0) {
             err = PyFile_WriteObject(suggestions, f, Py_PRINT_RAW);
+            err += PyFile_WriteString("?", f);
         }
         Py_DECREF(suggestions);
     }
@@ -1089,7 +1090,6 @@ PyErr_Display(PyObject *exception, PyObject *value, PyObject *tb)
     if (file == Py_None) {
         return;
     }
-
     Py_INCREF(file);
     _PyErr_Display(file, exception, value, tb);
     Py_DECREF(file);

Python/pythonrun.c

@@ -1,14 +1,14 @@
 #include "Python.h"
 
-#include "pycore_suggestions.h"
+#include "pycore_pyerrors.h"
 
 #define MAX_GETATTR_PREDICT_DIST 3
 #define MAX_GETATTR_PREDICT_ITEMS 100
 #define MAX_GETATTR_STRING_SIZE 20
 
 /* Calculate the Levenshtein distance between string1 and string2 */
 static Py_ssize_t
-distance(const char *string1, const char *string2)
+levenshtein_distance(const char *string1, const char *string2)
 {
     Py_ssize_t len1 = strlen(string1);
     Py_ssize_t len2 = strlen(string2);
@@ -150,8 +150,8 @@ calculate_suggestions(PyObject* dir,
             PyErr_Clear();
             continue;
         }
-        Py_ssize_t current_distance = distance(PyUnicode_AsUTF8(name),
-                                               PyUnicode_AsUTF8(item));
+        Py_ssize_t current_distance = levenshtein_distance(PyUnicode_AsUTF8(name),
+                                                           PyUnicode_AsUTF8(item));
         if (current_distance > MAX_GETATTR_PREDICT_DIST){
             continue;
         }
@@ -163,7 +163,8 @@ calculate_suggestions(PyObject* dir,
     if (!suggestion) {
         return NULL;
     }
-    return PyUnicode_FromFormat("Did you mean: %U?", suggestion);
+    Py_INCREF(suggestion);
+    return suggestion;
 }
 
 static PyObject*
@@ -187,13 +188,15 @@ offer_suggestions_for_attribute_error(PyAttributeErrorObject* exc) {
 }
 
 
-// Offer suggestions for a given exception. This function does not raise exceptions
-// and returns NULL if no exception was found.
+// Offer suggestions for a given exception. Returns a python string object containing the
+// suggestions. This function does not raise exceptions and returns NULL if no suggestion was found.
 PyObject* _Py_Offer_Suggestions(PyObject* exception) {
-    assert(!PyErr_Occurred());
+    PyObject* result = NULL;
+    assert(!PyErr_Occurred()); // Check that we are not going to clean any existing exception
     if (PyErr_GivenExceptionMatches(exception, PyExc_AttributeError)) {
-        return offer_suggestions_for_attribute_error((PyAttributeErrorObject*) exception);
+        result = offer_suggestions_for_attribute_error((PyAttributeErrorObject*) exception);
     }
-    return NULL;
+    assert(!PyErr_Occurred());
+    return result;
 }