closes bpo-31902: Fix the col_offset attribute for ast.Async* nodes to point to the "async" keyword. (GH-4175)

Previously, col_offset points to the keyword after "async".
(cherry picked from commit 90fc8980bb)

Co-authored-by: guoci <zguoci@gmail.com>

Lib/test/test_ast.py

@@ -1181,12 +1181,12 @@ exec_results = [
 ('Module', [('Expr', (1, 0), ('DictComp', (1, 0), ('Name', (1, 1), 'a', ('Load',)), ('Name', (1, 5), 'b', ('Load',)), [('comprehension', ('Tuple', (1, 11), [('Name', (1, 11), 'v', ('Store',)), ('Name', (1, 13), 'w', ('Store',))], ('Store',)), ('Name', (1, 18), 'x', ('Load',)), [], 0)]))]),
 ('Module', [('Expr', (1, 0), ('SetComp', (1, 0), ('Name', (1, 1), 'r', ('Load',)), [('comprehension', ('Name', (1, 7), 'l', ('Store',)), ('Name', (1, 12), 'x', ('Load',)), [('Name', (1, 17), 'g', ('Load',))], 0)]))]),
 ('Module', [('Expr', (1, 0), ('SetComp', (1, 0), ('Name', (1, 1), 'r', ('Load',)), [('comprehension', ('Tuple', (1, 7), [('Name', (1, 7), 'l', ('Store',)), ('Name', (1, 9), 'm', ('Store',))], ('Store',)), ('Name', (1, 14), 'x', ('Load',)), [], 0)]))]),
-('Module', [('AsyncFunctionDef', (1, 6), 'f', ('arguments', [], None, [], [], None, []), [('Expr', (2, 1), ('Str', (2, 1), 'async function')), ('Expr', (3, 1), ('Await', (3, 1), ('Call', (3, 7), ('Name', (3, 7), 'something', ('Load',)), [], [])))], [], None)]),
+('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Expr', (2, 1), ('Str', (2, 1), 'async function')), ('Expr', (3, 1), ('Await', (3, 1), ('Call', (3, 7), ('Name', (3, 7), 'something', ('Load',)), [], [])))], [], None)]),
-('Module', [('AsyncFunctionDef', (1, 6), 'f', ('arguments', [], None, [], [], None, []), [('AsyncFor', (2, 7), ('Name', (2, 11), 'e', ('Store',)), ('Name', (2, 16), 'i', ('Load',)), [('Expr', (2, 19), ('Num', (2, 19), 1))], [('Expr', (3, 7), ('Num', (3, 7), 2))])], [], None)]),
+('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('AsyncFor', (2, 1), ('Name', (2, 11), 'e', ('Store',)), ('Name', (2, 16), 'i', ('Load',)), [('Expr', (2, 19), ('Num', (2, 19), 1))], [('Expr', (3, 7), ('Num', (3, 7), 2))])], [], None)]),
-('Module', [('AsyncFunctionDef', (1, 6), 'f', ('arguments', [], None, [], [], None, []), [('AsyncWith', (2, 7), [('withitem', ('Name', (2, 12), 'a', ('Load',)), ('Name', (2, 17), 'b', ('Store',)))], [('Expr', (2, 20), ('Num', (2, 20), 1))])], [], None)]),
+('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('AsyncWith', (2, 1), [('withitem', ('Name', (2, 12), 'a', ('Load',)), ('Name', (2, 17), 'b', ('Store',)))], [('Expr', (2, 20), ('Num', (2, 20), 1))])], [], None)]),
 ('Module', [('Expr', (1, 0), ('Dict', (1, 0), [None, ('Num', (1, 10), 2)], [('Dict', (1, 3), [('Num', (1, 4), 1)], [('Num', (1, 6), 2)]), ('Num', (1, 12), 3)]))]),
 ('Module', [('Expr', (1, 0), ('Set', (1, 0), [('Starred', (1, 1), ('Set', (1, 2), [('Num', (1, 3), 1), ('Num', (1, 6), 2)]), ('Load',)), ('Num', (1, 10), 3)]))]),
-('Module', [('AsyncFunctionDef', (1, 6), 'f', ('arguments', [], None, [], [], None, []), [('Expr', (2, 1), ('ListComp', (2, 2), ('Name', (2, 2), 'i', ('Load',)), [('comprehension', ('Name', (2, 14), 'b', ('Store',)), ('Name', (2, 19), 'c', ('Load',)), [], 1)]))], [], None)]),
+('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Expr', (2, 1), ('ListComp', (2, 2), ('Name', (2, 2), 'i', ('Load',)), [('comprehension', ('Name', (2, 14), 'b', ('Store',)), ('Name', (2, 19), 'c', ('Load',)), [], 1)]))], [], None)]),
 ]
 single_results = [
 ('Interactive', [('Expr', (1, 0), ('BinOp', (1, 0), ('Num', (1, 0), 1), ('Add',), ('Num', (1, 2), 2)))]),

Misc/NEWS.d/next/Core and Builtins/2017-10-30-12-44-50.bpo-31902.a07fa57.rst

@@ -0,0 +1,3 @@
+Fix the ``col_offset`` attribute for ast nodes ``ast.AsyncFor``,
+``ast.AsyncFunctionDef``, and ``ast.AsyncWith``. Previously, ``col_offset``
+pointed to the keyword after ``async``.

Python/ast.c

@@ -600,8 +600,8 @@ static asdl_seq *ast_for_exprlist(struct compiling *, const node *,
 static expr_ty ast_for_testlist(struct compiling *, const node *);
 static stmt_ty ast_for_classdef(struct compiling *, const node *, asdl_seq *);
 
-static stmt_ty ast_for_with_stmt(struct compiling *, const node *, int);
+static stmt_ty ast_for_with_stmt(struct compiling *, const node *, bool);
-static stmt_ty ast_for_for_stmt(struct compiling *, const node *, int);
+static stmt_ty ast_for_for_stmt(struct compiling *, const node *, bool);
 
 /* Note different signature for ast_for_call */
 static expr_ty ast_for_call(struct compiling *, const node *, expr_ty, bool);
@@ -1569,10 +1569,11 @@ ast_for_decorators(struct compiling *c, const node *n)
 }
 
 static stmt_ty
-ast_for_funcdef_impl(struct compiling *c, const node *n,
+ast_for_funcdef_impl(struct compiling *c, const node *n0,
-                     asdl_seq *decorator_seq, int is_async)
+                     asdl_seq *decorator_seq, bool is_async)
 {
     /* funcdef: 'def' NAME parameters ['->' test] ':' suite */
+    const node * const n = is_async ? CHILD(n0, 1) : n0;
     identifier name;
     arguments_ty args;
     asdl_seq *body;
@@ -1601,7 +1602,7 @@ ast_for_funcdef_impl(struct compiling *c, const node *n,
 
     if (is_async)
         return AsyncFunctionDef(name, args, body, decorator_seq, returns,
-                                LINENO(n), n->n_col_offset, c->c_arena);
+                                LINENO(n), n0->n_col_offset, c->c_arena);
     else
         return FunctionDef(name, args, body, decorator_seq, returns,
                            LINENO(n), n->n_col_offset, c->c_arena);
@@ -1616,8 +1617,8 @@ ast_for_async_funcdef(struct compiling *c, const node *n, asdl_seq *decorator_se
     assert(strcmp(STR(CHILD(n, 0)), "async") == 0);
     REQ(CHILD(n, 1), funcdef);
 
-    return ast_for_funcdef_impl(c, CHILD(n, 1), decorator_seq,
+    return ast_for_funcdef_impl(c, n, decorator_seq,
-                                1 /* is_async */);
+                                true /* is_async */);
 }
 
 static stmt_ty
@@ -1625,7 +1626,7 @@ ast_for_funcdef(struct compiling *c, const node *n, asdl_seq *decorator_seq)
 {
     /* funcdef: 'def' NAME parameters ['->' test] ':' suite */
     return ast_for_funcdef_impl(c, n, decorator_seq,
-                                0 /* is_async */);
+                                false /* is_async */);
 }
 
 
@@ -1639,15 +1640,15 @@ ast_for_async_stmt(struct compiling *c, const node *n)
 
     switch (TYPE(CHILD(n, 1))) {
         case funcdef:
-            return ast_for_funcdef_impl(c, CHILD(n, 1), NULL,
+            return ast_for_funcdef_impl(c, n, NULL,
-                                        1 /* is_async */);
+                                        true /* is_async */);
         case with_stmt:
-            return ast_for_with_stmt(c, CHILD(n, 1),
+            return ast_for_with_stmt(c, n,
-                                     1 /* is_async */);
+                                     true /* is_async */);
 
         case for_stmt:
-            return ast_for_for_stmt(c, CHILD(n, 1),
+            return ast_for_for_stmt(c, n,
-                                    1 /* is_async */);
+                                    true /* is_async */);
 
         default:
             PyErr_Format(PyExc_SystemError,
@@ -3681,8 +3682,9 @@ ast_for_while_stmt(struct compiling *c, const node *n)
 }
 
 static stmt_ty
-ast_for_for_stmt(struct compiling *c, const node *n, int is_async)
+ast_for_for_stmt(struct compiling *c, const node *n0, bool is_async)
 {
+    const node * const n = is_async ? CHILD(n0, 1) : n0;
     asdl_seq *_target, *seq = NULL, *suite_seq;
     expr_ty expression;
     expr_ty target, first;
@@ -3717,7 +3719,7 @@ ast_for_for_stmt(struct compiling *c, const node *n, int is_async)
 
     if (is_async)
         return AsyncFor(target, expression, suite_seq, seq,
-                        LINENO(n), n->n_col_offset,
+                        LINENO(n), n0->n_col_offset,
                         c->c_arena);
     else
         return For(target, expression, suite_seq, seq,
@@ -3869,8 +3871,9 @@ ast_for_with_item(struct compiling *c, const node *n)
 
 /* with_stmt: 'with' with_item (',' with_item)* ':' suite */
 static stmt_ty
-ast_for_with_stmt(struct compiling *c, const node *n, int is_async)
+ast_for_with_stmt(struct compiling *c, const node *n0, bool is_async)
 {
+    const node * const n = is_async ? CHILD(n0, 1) : n0;
     int i, n_items;
     asdl_seq *items, *body;
 
@@ -3892,7 +3895,7 @@ ast_for_with_stmt(struct compiling *c, const node *n, int is_async)
         return NULL;
 
     if (is_async)
-        return AsyncWith(items, body, LINENO(n), n->n_col_offset, c->c_arena);
+        return AsyncWith(items, body, LINENO(n), n0->n_col_offset, c->c_arena);
     else
         return With(items, body, LINENO(n), n->n_col_offset, c->c_arena);
 }