bpo-42214: Fix check for NOTEQUAL token in the PEG parser for the barry_as_flufl rule (GH-23048)

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Pablo Galindo 2020-10-30 23:48:42 +00:00 committed by GitHub
parent 6e03c0ad15
commit 06f8c3328d
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GPG Key ID: 4AEE18F83AFDEB23
6 changed files with 23 additions and 5 deletions

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@ -428,7 +428,7 @@ compare_op_bitwise_or_pair[CmpopExprPair*]:
| is_bitwise_or
eq_bitwise_or[CmpopExprPair*]: '==' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Eq, a) }
noteq_bitwise_or[CmpopExprPair*]:
| (tok='!=' {_PyPegen_check_barry_as_flufl(p) ? NULL : tok}) a=bitwise_or {_PyPegen_cmpop_expr_pair(p, NotEq, a) }
| (tok='!=' { _PyPegen_check_barry_as_flufl(p, tok) ? NULL : tok}) a=bitwise_or {_PyPegen_cmpop_expr_pair(p, NotEq, a) }
lte_bitwise_or[CmpopExprPair*]: '<=' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, LtE, a) }
lt_bitwise_or[CmpopExprPair*]: '<' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Lt, a) }
gte_bitwise_or[CmpopExprPair*]: '>=' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, GtE, a) }

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@ -955,6 +955,23 @@ pass
code += f"{' '*4*12}pass"
self._check_error(code, "too many statically nested blocks")
def test_barry_as_flufl_with_syntax_errors(self):
# The "barry_as_flufl" rule can produce some "bugs-at-a-distance" if
# is reading the wrong token in the presence of syntax errors later
# in the file. See bpo-42214 for more information.
code = """
def func1():
if a != b:
raise ValueError
def func2():
try
return 1
finally:
pass
"""
self._check_error(code, "invalid syntax")
def test_main():
support.run_unittest(SyntaxTestCase)
from test import test_syntax

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@ -0,0 +1,2 @@
Fixed a possible crash in the PEG parser when checking for the '!=' token in
the ``barry_as_flufl`` rule. Patch by Pablo Galindo.

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@ -21288,7 +21288,7 @@ _tmp_93_rule(Parser *p)
)
{
D(fprintf(stderr, "%*c+ _tmp_93[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'!='"));
_res = _PyPegen_check_barry_as_flufl ( p ) ? NULL : tok;
_res = _PyPegen_check_barry_as_flufl ( p , tok ) ? NULL : tok;
if (_res == NULL && PyErr_Occurred()) {
p->error_indicator = 1;
D(p->level--);

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@ -62,8 +62,7 @@ init_normalization(Parser *p)
/* Checks if the NOTEQUAL token is valid given the current parser flags
0 indicates success and nonzero indicates failure (an exception may be set) */
int
_PyPegen_check_barry_as_flufl(Parser *p) {
Token *t = p->tokens[p->fill - 1];
_PyPegen_check_barry_as_flufl(Parser *p, Token* t) {
assert(t->bytes != NULL);
assert(t->type == NOTEQUAL);

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@ -263,7 +263,7 @@ expr_ty _PyPegen_collect_call_seqs(Parser *, asdl_expr_seq *, asdl_seq *,
int end_col_offset, PyArena *arena);
expr_ty _PyPegen_concatenate_strings(Parser *p, asdl_seq *);
asdl_seq *_PyPegen_join_sequences(Parser *, asdl_seq *, asdl_seq *);
int _PyPegen_check_barry_as_flufl(Parser *);
int _PyPegen_check_barry_as_flufl(Parser *, Token *);
mod_ty _PyPegen_make_module(Parser *, asdl_stmt_seq *);
// Error reporting helpers