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gh-93671: Avoid exponential backtracking in deeply nested sequence patterns in match statements (GH-93680)

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Co-authored-by: Łukasz Langa <lukasz@langa.pl>
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Pablo Galindo Salgado 2022-06-10 16:56:45 +01:00 • committed by GitHub
parent 21a9a85ff4
commit 53a8b17895
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4 changed files with 36 additions and 3 deletions
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@ -471,7 +471,7 @@ or_pattern[pattern_ty]:
| patterns[asdl_pattern_seq*]='|'.closed_pattern+ {
asdl_seq_LEN(patterns) == 1 ? asdl_seq_GET(patterns, 0) : _PyAST_MatchOr(patterns, EXTRA) }
closed_pattern[pattern_ty]:
closed_pattern[pattern_ty] (memo):
| literal_pattern
| capture_pattern
| wildcard_pattern
@ -558,7 +558,7 @@ maybe_star_pattern[pattern_ty]:
| star_pattern
| pattern
star_pattern[pattern_ty]:
star_pattern[pattern_ty] (memo):
| '*' target=pattern_capture_target {
_PyAST_MatchStar(target->v.Name.id, EXTRA) }
| '*' wildcard_pattern {
@ -1312,4 +1312,4 @@ invalid_kvpair:
| a=expression !(':') {
RAISE_ERROR_KNOWN_LOCATION(p, PyExc_SyntaxError, a->lineno, a->end_col_offset - 1, a->end_lineno, -1, "':' expected after dictionary key") }
| expression ':' a='*' bitwise_or { RAISE_SYNTAX_ERROR_STARTING_FROM(a, "cannot use a starred expression in a dictionary value") }
| expression a=':' {RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expression expected after dictionary key and ':'") }
| expression a=':' {RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expression expected after dictionary key and ':'") }