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bpo-40334: Allow trailing comma in parenthesized context managers #19964

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Merged
merged 1 commit into from
May 6, 2020
+79 −7
Merged

bpo-40334: Allow trailing comma in parenthesized context managers #19964

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4 changes: 2 additions & 2 deletions Grammar/python.gram
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Original file line number Diff line number Diff line change
Expand Up @@ -170,11 +170,11 @@ for_stmt[stmt_ty]:
CHECK_VERSION(5, "Async for loops are", _Py_AsyncFor(t, ex, b, el, NEW_TYPE_COMMENT(p, tc), EXTRA)) }

with_stmt[stmt_ty]:
| 'with' '(' a=','.with_item+ ')' ':' b=block {
| 'with' '(' a=','.with_item+ ','? ')' ':' b=block {
_Py_With(a, b, NULL, EXTRA) }
| 'with' a=','.with_item+ ':' tc=[TYPE_COMMENT] b=block {
_Py_With(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) }
| ASYNC 'with' '(' a=','.with_item+ ')' ':' b=block {
| ASYNC 'with' '(' a=','.with_item+ ','? ')' ':' b=block {
CHECK_VERSION(5, "Async with statements are", _Py_AsyncWith(a, b, NULL, EXTRA)) }
| ASYNC 'with' a=','.with_item+ ':' tc=[TYPE_COMMENT] b=block {
CHECK_VERSION(5, "Async with statements are", _Py_AsyncWith(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA)) }
Expand Down
66 changes: 65 additions & 1 deletion Lib/test/test_grammar.py
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
# Python test set -- part 1, grammar.
# This just tests whether the parser accepts them all.

from test.support import check_syntax_error, check_syntax_warning
from test.support import check_syntax_error, check_syntax_warning, use_old_parser
import inspect
import unittest
import sys
Expand Down Expand Up @@ -1694,6 +1694,70 @@ def __exit__(self, *args):
with manager() as x, manager():
pass

if not use_old_parser():
test_cases = [
"""if 1:
with (
manager()
):
pass
""",
"""if 1:
with (
manager() as x
):
pass
""",
"""if 1:
with (
manager() as (x, y),
manager() as z,
):
pass
""",
"""if 1:
with (
manager(),
manager()
):
pass
""",
"""if 1:
with (
manager() as x,
manager() as y
):
pass
""",
"""if 1:
with (
manager() as x,
manager()
):
pass
""",
"""if 1:
with (
manager() as x,
manager() as y,
manager() as z,
):
pass
""",
"""if 1:
with (
manager() as x,
manager() as y,
manager(),
):
pass
""",
]
for case in test_cases:
with self.subTest(case=case):
compile(case, "<string>", "exec")


def test_if_else_expr(self):
# Test ifelse expressions in various cases
def _checkeval(msg, ret):
Expand Down
16 changes: 12 additions & 4 deletions Parser/pegen/parse.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3031,9 +3031,9 @@ for_stmt_rule(Parser *p)
}

// with_stmt:
// | 'with' '(' ','.with_item+ ')' ':' block
// | 'with' '(' ','.with_item+ ','? ')' ':' block
// | 'with' ','.with_item+ ':' TYPE_COMMENT? block
// | ASYNC 'with' '(' ','.with_item+ ')' ':' block
// | ASYNC 'with' '(' ','.with_item+ ','? ')' ':' block
// | ASYNC 'with' ','.with_item+ ':' TYPE_COMMENT? block
static stmt_ty
with_stmt_rule(Parser *p)
Expand All @@ -3051,20 +3051,24 @@ with_stmt_rule(Parser *p)
UNUSED(start_lineno); // Only used by EXTRA macro
int start_col_offset = p->tokens[mark]->col_offset;
UNUSED(start_col_offset); // Only used by EXTRA macro
{ // 'with' '(' ','.with_item+ ')' ':' block
{ // 'with' '(' ','.with_item+ ','? ')' ':' block
asdl_seq * a;
asdl_seq* b;
Token * keyword;
Token * literal;
Token * literal_1;
Token * literal_2;
void *opt_var;
UNUSED(opt_var); // Silence compiler warnings
if (
(keyword = _PyPegen_expect_token(p, 519))
&&
(literal = _PyPegen_expect_token(p, 7))
&&
(a = _gather_38_rule(p))
&&
(opt_var = _PyPegen_expect_token(p, 12), 1)
&&
(literal_1 = _PyPegen_expect_token(p, 8))
&&
(literal_2 = _PyPegen_expect_token(p, 11))
Expand Down Expand Up @@ -3124,14 +3128,16 @@ with_stmt_rule(Parser *p)
}
p->mark = mark;
}
{ // ASYNC 'with' '(' ','.with_item+ ')' ':' block
{ // ASYNC 'with' '(' ','.with_item+ ','? ')' ':' block
asdl_seq * a;
Token * async_var;
asdl_seq* b;
Token * keyword;
Token * literal;
Token * literal_1;
Token * literal_2;
void *opt_var;
UNUSED(opt_var); // Silence compiler warnings
if (
(async_var = _PyPegen_expect_token(p, ASYNC))
&&
Expand All @@ -3141,6 +3147,8 @@ with_stmt_rule(Parser *p)
&&
(a = _gather_42_rule(p))
&&
(opt_var = _PyPegen_expect_token(p, 12), 1)
&&
(literal_1 = _PyPegen_expect_token(p, 8))
&&
(literal_2 = _PyPegen_expect_token(p, 11))
Expand Down