Skip to content

Implement LWG-3721: Allow an arg-id with a value of zero for width in std-format-spec #2906

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Stephan T. Lavavej (StephanTLavavej) merged 5 commits into from
Jul 28, 2022
Merged

Implement LWG-3721: Allow an arg-id with a value of zero for width in std-format-spec #2906

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
2b512c7
Zero dynamic width doesn't lead to death (LWG-3721)
frederick-vs-ja Jul 25, 2022
76d8a02
Test coverage for LWG-3721
frederick-vs-ja Jul 25, 2022
3e66d6a
Implement LWG-3721
frederick-vs-ja Jul 25, 2022
edf4c39
Consistency improvements
frederick-vs-ja Jul 25, 2022
50677c0
Add failure test for negative dynamic width
CaseyCarter Jul 27, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 4 additions & 9 deletions stl/inc/format
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1421,15 +1421,10 @@ public:
template <class _Ty>
_NODISCARD constexpr unsigned long long operator()(const _Ty _Value) const {
if constexpr (is_integral_v<_Ty>) {
bool _Positive;
if constexpr (same_as<_Ty, bool>) { // avoid "bool > 0", which triggers C4804
_Positive = _Value != 0;
} else {
_Positive = _Value > 0;
}

if (!_Positive) {
_Throw_format_error("width is not positive.");
if constexpr (is_signed_v<_Ty>) {
if (_Value < 0) {
_Throw_format_error("Negative width.");
}
}
return static_cast<unsigned long long>(_Value);
} else {
Expand Down
6 changes: 3 additions & 3 deletions tests/std/tests/P0645R10_text_formatting_death/test.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,8 @@ void test_case_advance_no_range() {
context.advance_to(other_format_string.begin());
}

void test_case_zero_dynamic_width() {
(void) format("{:{}}", 42, 0);
void test_case_negative_dynamic_width() {
Comment thread
StephanTLavavej marked this conversation as resolved.
(void) format("{:{}}", 42, -2);
}

int main(int argc, char* argv[]) {
Expand All @@ -27,7 +27,7 @@ int main(int argc, char* argv[]) {
#if _ITERATOR_DEBUG_LEVEL != 0
exec.add_death_tests({
test_case_advance_no_range,
test_case_zero_dynamic_width,
test_case_negative_dynamic_width,
});
#endif // _ITERATOR_DEBUG_LEVEL != 0

Expand Down
2 changes: 2 additions & 0 deletions tests/std/tests/P0645R10_text_formatting_formatting/test.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1287,6 +1287,8 @@ void libfmt_formatter_test_runtime_width() {
== STR(" 0")); // behavior differs from libfmt, but conforms
throw_helper(STR("{0:{1}}"), 0, 0.0);

assert(format(STR("{0:{1}}"), 42, 0) == STR("42")); // LWG-3721: zero dynamic width is OK

assert(format(STR("{0:{1}}"), -42, 4) == STR(" -42"));
assert(format(STR("{0:{1}}"), 42u, 5) == STR(" 42"));
assert(format(STR("{0:{1}}"), -42l, 6) == STR(" -42"));
Expand Down