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<regex>: Do not reset matched capture groups in POSIX regexes #5377

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Merged
StephanTLavavej merged 3 commits into from
Apr 10, 2025
Merged

<regex>: Do not reset matched capture groups in POSIX regexes #5377

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03e524f
`<regex>`: Do not reset matched capture groups in POSIX regexes
muellerj2 Mar 28, 2025
15666ea
Code review feedback.
StephanTLavavej Apr 3, 2025
8780bbf
Merge branch 'main' into regex-do-not-reset-capture-groups-for-posix-…
StephanTLavavej Apr 10, 2025
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10 changes: 7 additions & 3 deletions stl/inc/regex
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Original file line number Diff line number Diff line change
Expand Up @@ -3641,9 +3641,13 @@ bool _Matcher<_BidIt, _Elem, _RxTraits, _It>::_Match_pat(_Node_base* _Nx) { // c
{ // record current position
_Node_capture* _Node = static_cast<_Node_capture*>(_Nx);
_Tgt_state._Grps[_Node->_Idx]._Begin = _Tgt_state._Cur;
// CodeQL [SM02323] Comparing unchanging unsigned int _Node->_Idx to decreasing size_t _Idx is safe.
for (size_t _Idx = _Tgt_state._Grp_valid.size(); _Node->_Idx < _Idx;) {
_Tgt_state._Grp_valid[--_Idx] = false;
if (!(_Sflags
& (regex_constants::basic | regex_constants::extended | regex_constants::grep
| regex_constants::egrep | regex_constants::awk))) {
// CodeQL [SM02323] Comparing unchanging unsigned int _Node->_Idx to decreasing size_t _Idx is safe.
for (size_t _Idx = _Tgt_state._Grp_valid.size(); _Node->_Idx < _Idx;) {
_Tgt_state._Grp_valid[--_Idx] = false;
}
}

break;
Expand Down
42 changes: 42 additions & 0 deletions tests/std/tests/VSO_0000000_regex_use/test.cpp
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Expand Up @@ -1457,6 +1457,47 @@ void test_gh_5374() {
g_regexTester.should_match("bc", R"((a*)b\1c)", ECMAScript);
}

void test_gh_5377() {
// GH-5377 <regex>: Do not reset matched capture groups in POSIX regexes
for (syntax_option_type option : {extended, awk, egrep}) {
test_regex abcd_regex(&g_regexTester, R"(^((a)|(b)|(c)|(d))+$)", option);
abcd_regex.should_search_match_capture_groups(
"abcd", "abcd", match_default, {{3, 4}, {0, 1}, {1, 2}, {2, 3}, {3, 4}});
abcd_regex.should_search_match_capture_groups(
"acbd", "acbd", match_default, {{3, 4}, {0, 1}, {2, 3}, {1, 2}, {3, 4}});
abcd_regex.should_search_match_capture_groups(
"dcba", "dcba", match_default, {{3, 4}, {3, 4}, {2, 3}, {1, 2}, {0, 1}});
}

for (syntax_option_type option : {basic, grep}) {
test_regex abcd_regex(&g_regexTester, R"(^\(\(a\)*\(b\)*\(c\)*\(d\)*\)*$)", option);
abcd_regex.should_search_match_capture_groups(
"abcd", "abcd", match_default, {{0, 4}, {0, 1}, {1, 2}, {2, 3}, {3, 4}});
abcd_regex.should_search_match_capture_groups(
"acbd", "acbd", match_default, {{2, 4}, {0, 1}, {2, 3}, {1, 2}, {3, 4}});
abcd_regex.should_search_match_capture_groups(
"dcba", "dcba", match_default, {{3, 4}, {3, 4}, {2, 3}, {1, 2}, {0, 1}});

test_regex backref_regex(&g_regexTester, R"(^\(\(a\)\{0,1\}\(\2b\)\{0,1\}\)*)", option);
backref_regex.should_search_match_capture_groups("aaababb", "aaabab", match_default, {{4, 6}, {1, 2}, {4, 6}});
}

{
// ECMAScript's behavior is different:
test_regex abcd_regex(&g_regexTester, R"(^((a)|(b)|(c)|(d))+$)", ECMAScript);
abcd_regex.should_search_match_capture_groups(
"abcd", "abcd", match_default, {{3, 4}, {-1, -1}, {-1, -1}, {-1, -1}, {3, 4}});
abcd_regex.should_search_match_capture_groups(
"acbd", "acbd", match_default, {{3, 4}, {-1, -1}, {-1, -1}, {-1, -1}, {3, 4}});
abcd_regex.should_search_match_capture_groups(
"dcba", "dcba", match_default, {{3, 4}, {3, 4}, {-1, -1}, {-1, -1}, {-1, -1}});

test_regex backref_regex(&g_regexTester, R"(^((a){0,1}(\2b){0,1})*)", ECMAScript);
backref_regex.should_search_match_capture_groups(
"aaababb", "aaababb", match_default, {{6, 7}, {-1, -1}, {6, 7}});
}
}

int main() {
test_dev10_449367_case_insensitivity_should_work();
test_dev11_462743_regex_collate_should_not_disable_regex_icase();
Expand Down Expand Up @@ -1499,6 +1540,7 @@ int main() {
test_gh_5364();
test_gh_5371();
test_gh_5374();
test_gh_5377();

return g_regexTester.result();
}