When parsing a time with %R or %T we should ignore out of range hours
and minutes if the type being parsed doesn't need them, e.g. when
parsing a chrono::year_month_day from "2026-07-29 99:99:99" we do not
set failbit, and should continue parsing after the invalid hours and
minutes.
Because we were short circuiting as soon as we saw "99" (in either
field) we didn't parse to the end of the %R or %T field, and then could
set failbit if there were any subsequent characters or flags to parse.
The fix is to only short-circuit when setting failbit, and continue
parsing otherwise.
libstdc++-v3/ChangeLog:
PR libstdc++/126364
* include/bits/chrono_io.h (_Parser::operator()) <R>: Only break
early when setting failbit.
* testsuite/std/time/parse/126364.cc: New test.
---
Tested x86_64-linux.
This should be backported to 14, 15 and 16 as well.
libstdc++-v3/include/bits/chrono_io.h | 12 ++++---
.../testsuite/std/time/parse/126364.cc | 34 +++++++++++++++++++
2 files changed, 42 insertions(+), 4 deletions(-)
create mode 100644 libstdc++-v3/testsuite/std/time/parse/126364.cc
diff --git a/libstdc++-v3/include/bits/chrono_io.h
b/libstdc++-v3/include/bits/chrono_io.h
index c5170368f82f..51e07ff55593 100644
--- a/libstdc++-v3/include/bits/chrono_io.h
+++ b/libstdc++-v3/include/bits/chrono_io.h
@@ -4737,8 +4737,10 @@ namespace __detail
if (__val == -1 || __val > 23) [[unlikely]]
{
if ((_M_need & _ChronoParts::_TimeOfDay) != 0)
- __err |= ios_base::failbit;
- break;
+ {
+ __err |= ios_base::failbit;
+ break;
+ }
}
if (!__read_chr(':')) [[unlikely]]
break;
@@ -4748,8 +4750,10 @@ namespace __detail
if (__val == -1 || __val > 60) [[unlikely]]
{
if ((_M_need & _ChronoParts::_TimeOfDay) != 0)
- __err |= ios_base::failbit;
- break;
+ {
+ __err |= ios_base::failbit;
+ break;
+ }
}
__min = minutes(__val);
diff --git a/libstdc++-v3/testsuite/std/time/parse/126364.cc
b/libstdc++-v3/testsuite/std/time/parse/126364.cc
new file mode 100644
index 000000000000..74a94a6b84b8
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/time/parse/126364.cc
@@ -0,0 +1,34 @@
+// { dg-do run { target c++20 } }
+
+// Bug 126364 - chrono::from_stream %T and %R short circuit on out of range
+// values even when it doesn't fail the parse
+
+#include <chrono>
+#include <sstream>
+#include <testsuite_hooks.h>
+
+using namespace std::chrono;
+
+void
+test_pr126364()
+{
+ auto check = [](const char* input, char const* fmt) {
+ std::istringstream is(input);
+ year_month_day ymd{};
+ return from_stream(is, fmt, ymd).good() && ymd.ok();
+ };
+
+ VERIFY( check("2019-09-05T25:36:57Z", "%FT%TZ") ); // hour 25 only
+ VERIFY( check("2019-09-05T20:99:57Z", "%FT%TZ") ); // minute 99 only
+ VERIFY( check("2019-09-05T20:36:99Z", "%FT%TZ") ); // second 99 only
+ VERIFY( check("2019-09-05T25:36:57Z", "%FT%T") ); // hour 25 only, no Z
+ VERIFY( check("2019-09-05T20:99:57Z", "%FT%T") ); // minute 99 only, no Z
+ VERIFY( check("2019-09-05T20:36:99Z", "%FT%T") ); // second 99 only, no Z
+ VERIFY( check("2019-09-05 25", "%F %H") ); // %H out of range alone
+ VERIFY( check("2019-09-05 99", "%F %M") ); // %M out of range alone
+}
+
+int main()
+{
+ test_pr126364();
+}
--
2.55.0
