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Merged
merged 5 commits into from
Oct 26, 2017
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bpo-28936: Detect lexically first syntax error first #4097

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06a3914
Lexically first global and nonlocal syntax errors at given scope shou…
ilevkivskyi Oct 23, 2017
90e8678
Add NEWS entry
ilevkivskyi Oct 23, 2017
528f9f9
Merge branch 'master' into fix-globak-first
ilevkivskyi Oct 23, 2017
e431ad1
Address CR
ilevkivskyi Oct 25, 2017
4f87c99
Address CR
ilevkivskyi Oct 26, 2017
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36 changes: 27 additions & 9 deletions Lib/test/test_syntax.py
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Original file line number Diff line number Diff line change
Expand Up @@ -399,13 +399,26 @@

Misuse of the nonlocal and global statement can lead to a few unique syntax errors.

>>> def f():
... print(x)
... global x
Traceback (most recent call last):
...
SyntaxError: name 'x' is used prior to global declaration

>>> def f():
... x = 1
... global x
Traceback (most recent call last):
...
SyntaxError: name 'x' is assigned to before global declaration

>>> def f(x):
... global x
Traceback (most recent call last):
...
SyntaxError: name 'x' is parameter and global

>>> def f():
... x = 1
... def g():
Expand Down Expand Up @@ -560,7 +573,6 @@

import re
import unittest
import warnings

from test import support

Expand Down Expand Up @@ -596,19 +608,25 @@ def test_assign_call(self):
def test_assign_del(self):
self._check_error("del f()", "delete")

def test_global_err_then_warn(self):
# Bug #763201: The SyntaxError raised for one global statement
# shouldn't be clobbered by a SyntaxWarning issued for a later one.
def test_global_param_err_first(self):
source = """if 1:
def error(a):
global a # SyntaxError
def warning():
def error2():
b = 1
global b # SyntaxError
"""
self._check_error(source, "parameter and global", lineno=3)

def test_nonlocal_param_err_first(self):
source = """if 1:
def error(a):
nonlocal a # SyntaxError
def error2():
b = 1
global b # SyntaxWarning
global b # SyntaxError
"""
warnings.filterwarnings(action='ignore', category=SyntaxWarning)
self._check_error(source, "global")
warnings.filters.pop(0)
self._check_error(source, "parameter and nonlocal", lineno=3)

def test_break_outside_loop(self):
self._check_error("break", "outside loop")
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2017-10-23-23-39-26.bpo-28936.C288Jh.rst
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@@ -0,0 +1,2 @@
Ensure that lexically first syntax error involving a parameter and ``global``
or ``nonlocal`` is detected first at a given scope. Patch by Ivan Levkivskyi.
34 changes: 16 additions & 18 deletions Python/symtable.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,12 @@
#include "structmember.h"

/* error strings used for warnings */
#define GLOBAL_PARAM \
"name '%U' is parameter and global"

#define NONLOCAL_PARAM \
"name '%U' is parameter and nonlocal"

#define GLOBAL_AFTER_ASSIGN \
"name '%U' is assigned to before global declaration"

Expand Down Expand Up @@ -465,12 +471,6 @@ analyze_name(PySTEntryObject *ste, PyObject *scopes, PyObject *name, long flags,
PyObject *global)
{
if (flags & DEF_GLOBAL) {
if (flags & DEF_PARAM) {
PyErr_Format(PyExc_SyntaxError,
"name '%U' is parameter and global",
name);
return error_at_directive(ste, name);
}
if (flags & DEF_NONLOCAL) {
PyErr_Format(PyExc_SyntaxError,
"name '%U' is nonlocal and global",
Expand All @@ -485,12 +485,6 @@ analyze_name(PySTEntryObject *ste, PyObject *scopes, PyObject *name, long flags,
return 1;
}
if (flags & DEF_NONLOCAL) {
if (flags & DEF_PARAM) {
PyErr_Format(PyExc_SyntaxError,
"name '%U' is parameter and nonlocal",
name);
return error_at_directive(ste, name);
}
if (!bound) {
PyErr_Format(PyExc_SyntaxError,
"nonlocal declaration not allowed at module level");
Expand Down Expand Up @@ -1284,9 +1278,11 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
long cur = symtable_lookup(st, name);
if (cur < 0)
VISIT_QUIT(st, 0);
if (cur & (DEF_LOCAL | USE | DEF_ANNOT)) {
char* msg;
if (cur & USE) {
if (cur & (DEF_PARAM | DEF_LOCAL | USE | DEF_ANNOT)) {
const char* msg;
if (cur & DEF_PARAM) {
msg = GLOBAL_PARAM;
} else if (cur & USE) {
msg = GLOBAL_AFTER_USE;
} else if (cur & DEF_ANNOT) {
msg = GLOBAL_ANNOT;
Expand Down Expand Up @@ -1315,9 +1311,11 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
long cur = symtable_lookup(st, name);
if (cur < 0)
VISIT_QUIT(st, 0);
if (cur & (DEF_LOCAL | USE | DEF_ANNOT)) {
char* msg;
if (cur & USE) {
if (cur & (DEF_PARAM | DEF_LOCAL | USE | DEF_ANNOT)) {
const char* msg;
if (cur & DEF_PARAM) {
msg = NONLOCAL_PARAM;
} else if (cur & USE) {
msg = NONLOCAL_AFTER_USE;
} else if (cur & DEF_ANNOT) {
msg = NONLOCAL_ANNOT;
Expand Down