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bpo-32023: Disallow genexprs without parenthesis in class definitions. (#4400)

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Serhiy Storchaka 2017-11-15 17:39:37 +02:00 committed by GitHub
parent edad8eebee
commit ddbce13786
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 23 additions and 7 deletions
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8
Doc/whatsnew/3.7.rst
View File

@ -638,10 +638,14 @@ Changes in Python behavior
f(1 for x in [1],)
class C(1 for x in [1]):
pass
Python 3.7 now correctly raises a :exc:`SyntaxError`, as a generator
expression always needs to be directly inside a set of parentheses
and cannot have a comma on either side.
(Contributed by Serhiy Storchaka in :issue:`32012`.)
and cannot have a comma on either side, and the duplication of the
parentheses can be omitted only on calls.
(Contributed by Serhiy Storchaka in :issue:`32012` and :issue:`32023`.)
Changes in the Python API

4
Lib/test/test_syntax.py
View File

@ -153,6 +153,10 @@ Traceback (most recent call last):
SyntaxError: Generator expression must be parenthesized
>>> f((x for x in L), 1)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> class C(x for x in L):
... pass
Traceback (most recent call last):
SyntaxError: invalid syntax
>>> def g(*args, **kwargs):
... print(args, sorted(kwargs.items()))

3
Misc/NEWS.d/next/Core and Builtins/2017-11-15-10-49-35.bpo-32023.XnCGT5.rst Normal file
View File

@ -0,0 +1,3 @@
SyntaxError is now correctly raised when a generator expression without
parenthesis is used instead of an inheritance list in a class definition.
The duplication of the parentheses can be omitted only on calls.

15
Python/ast.c
View File

@ -11,6 +11,7 @@
#include "pythonrun.h"
#include <assert.h>
#include <stdbool.h>
static int validate_stmts(asdl_seq *);
static int validate_exprs(asdl_seq *, expr_context_ty, int);
@ -611,7 +612,7 @@ static stmt_ty ast_for_with_stmt(struct compiling *, const node *, int);
static stmt_ty ast_for_for_stmt(struct compiling *, const node *, int);
/* Note different signature for ast_for_call */
static expr_ty ast_for_call(struct compiling *, const node *, expr_ty);
static expr_ty ast_for_call(struct compiling *, const node *, expr_ty, bool);
static PyObject *parsenumber(struct compiling *, const char *);
static expr_ty parsestrplus(struct compiling *, const node *n);
@ -1545,7 +1546,7 @@ ast_for_decorator(struct compiling *c, const node *n)
name_expr = NULL;
}
else {
d = ast_for_call(c, CHILD(n, 3), name_expr);
d = ast_for_call(c, CHILD(n, 3), name_expr, true);
if (!d)
return NULL;
name_expr = NULL;
@ -2368,7 +2369,7 @@ ast_for_trailer(struct compiling *c, const node *n, expr_ty left_expr)
return Call(left_expr, NULL, NULL, LINENO(n),
n->n_col_offset, c->c_arena);
else
return ast_for_call(c, CHILD(n, 1), left_expr);
return ast_for_call(c, CHILD(n, 1), left_expr, true);
}
else if (TYPE(CHILD(n, 0)) == DOT) {
PyObject *attr_id = NEW_IDENTIFIER(CHILD(n, 1));
@ -2705,7 +2706,7 @@ ast_for_expr(struct compiling *c, const node *n)
}
static expr_ty
ast_for_call(struct compiling *c, const node *n, expr_ty func)
ast_for_call(struct compiling *c, const node *n, expr_ty func, bool allowgen)
{
/*
arglist: argument (',' argument)* [',']
@ -2728,6 +2729,10 @@ ast_for_call(struct compiling *c, const node *n, expr_ty func)
nargs++;
else if (TYPE(CHILD(ch, 1)) == comp_for) {
nargs++;
if (!allowgen) {
ast_error(c, ch, "invalid syntax");
return NULL;
}
if (NCH(n) > 1) {
ast_error(c, ch, "Generator expression must be parenthesized");
return NULL;
@ -3973,7 +3978,7 @@ ast_for_classdef(struct compiling *c, const node *n, asdl_seq *decorator_seq)
if (!dummy_name)
return NULL;
dummy = Name(dummy_name, Load, LINENO(n), n->n_col_offset, c->c_arena);
call = ast_for_call(c, CHILD(n, 3), dummy);
call = ast_for_call(c, CHILD(n, 3), dummy, false);
if (!call)
return NULL;
}