bpo-36280: Add Constant.kind field (GH-12295)

The value is a string for string and byte literals, None otherwise.
It is 'u' for u"..." literals, 'b' for b"..." literals, '' for "..." literals.
The 'r' (raw) prefix is ignored.
Does not apply to f-strings.

This appears sufficient to make mypy capable of using the stdlib ast module instead of typed_ast (assuming a mypy patch I'm working on).

WIP: I need to make the tests pass. @ilevkivskyi @serhiy-storchaka 



https://bugs.python.org/issue36280

1 files changed, 27 insertions, 5 deletions

diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 0411f9f07f..d0416eb639 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -324,8 +324,10 @@ static char *JoinedStr_fields[]={
     "values",
 };
 static PyTypeObject *Constant_type;
+_Py_IDENTIFIER(kind);
 static char *Constant_fields[]={
     "value",
+    "kind",
 };
 static PyTypeObject *Attribute_type;
 _Py_IDENTIFIER(attr);
@@ -950,7 +952,7 @@ static int init_types(void)
     if (!FormattedValue_type) return 0;
     JoinedStr_type = make_type("JoinedStr", expr_type, JoinedStr_fields, 1);
     if (!JoinedStr_type) return 0;
-    Constant_type = make_type("Constant", expr_type, Constant_fields, 1);
+    Constant_type = make_type("Constant", expr_type, Constant_fields, 2);
     if (!Constant_type) return 0;
     Attribute_type = make_type("Attribute", expr_type, Attribute_fields, 3);
     if (!Attribute_type) return 0;
@@ -2287,8 +2289,8 @@ JoinedStr(asdl_seq * values, int lineno, int col_offset, int end_lineno, int
 }
 
 expr_ty
-Constant(constant value, int lineno, int col_offset, int end_lineno, int
-         end_col_offset, PyArena *arena)
+Constant(constant value, string kind, int lineno, int col_offset, int
+         end_lineno, int end_col_offset, PyArena *arena)
 {
     expr_ty p;
     if (!value) {
@@ -2301,6 +2303,7 @@ Constant(constant value, int lineno, int col_offset, int end_lineno, int
         return NULL;
     p->kind = Constant_kind;
     p->v.Constant.value = value;
+    p->v.Constant.kind = kind;
     p->lineno = lineno;
     p->col_offset = col_offset;
     p->end_lineno = end_lineno;
@@ -3507,6 +3510,11 @@ ast2obj_expr(void* _o)
         if (_PyObject_SetAttrId(result, &PyId_value, value) == -1)
             goto failed;
         Py_DECREF(value);
+        value = ast2obj_string(o->v.Constant.kind);
+        if (!value) goto failed;
+        if (_PyObject_SetAttrId(result, &PyId_kind, value) == -1)
+            goto failed;
+        Py_DECREF(value);
         break;
     case Attribute_kind:
         result = PyType_GenericNew(Attribute_type, NULL, NULL);
@@ -7224,6 +7232,7 @@ obj2ast_expr(PyObject* obj, expr_ty* out, PyArena* arena)
     }
     if (isinstance) {
         constant value;
+        string kind;
 
         if (_PyObject_LookupAttrId(obj, &PyId_value, &tmp) < 0) {
             return 1;
@@ -7238,8 +7247,21 @@ obj2ast_expr(PyObject* obj, expr_ty* out, PyArena* arena)
             if (res != 0) goto failed;
             Py_CLEAR(tmp);
         }
-        *out = Constant(value, lineno, col_offset, end_lineno, end_col_offset,
-                        arena);
+        if (_PyObject_LookupAttrId(obj, &PyId_kind, &tmp) < 0) {
+            return 1;
+        }
+        if (tmp == NULL || tmp == Py_None) {
+            Py_CLEAR(tmp);
+            kind = NULL;
+        }
+        else {
+            int res;
+            res = obj2ast_string(tmp, &kind, arena);
+            if (res != 0) goto failed;
+            Py_CLEAR(tmp);
+        }
+        *out = Constant(value, kind, lineno, col_offset, end_lineno,
+                        end_col_offset, arena);
         if (*out == NULL) goto failed;
         return 0;
     }